Service Manual2007 Captiva SYMPTOM DIAGNOSIS

Captiva

SYMPTOM DIAGNOSIS

Symptoms - Engine Controls

Symptoms Description

Driveability symptoms do not set DTCs. The driveability symptoms are defined below. Certain conditions can cause multiple symptoms. These conditions are listed together. Additional conditions that may only cause certain symptoms are listed separately. Perform the Symptoms Testing before using the Additional Symptoms Tests.

Symptoms Definition

Backfire:

Fuel ignites in the intake manifold or in the exhaust system, making a loud popping noise.

Cuts Out, Misses:

A steady pulsation or jerking that follows engine speed, which is usually more pronounced as the engine load increases. This condition is not normally felt above 1500 RPM or 48 km/h (30 mph). The exhaust has a steady spitting sound at idle or at low speed.

Detonation/Spark Knock:

A mild to severe ping which usually occurs worse while under acceleration. The engine makes sharp metallic knocks that change with throttle opening.

Dieseling, Run-On:

Fuel ignites in the intake manifold or in the exhaust system, making a loud popping noise.

Hard Start:

Engine cranks OK, but does not start for a long time. The vehicle does eventually run, or may start but immediately stalls.

Hesitation, Sag, Stumble:

Momentary lack of response as the accelerator is pushed down. This condition can occur at any vehicle speed. This condition is usually more pronounced when first trying to make the vehicle move, as from a stop. This condition may cause the engine to stall in severe conditions.

Lack of Power, Sluggishness, or Sponginess:

The engine delivers less than expected power. Little or no increase in speed when the accelerator pedal is pushed down part way.

Poor Fuel Economy:

Fuel economy, as measured by an actual road test, is noticeably lower than expected. Also, the fuel economy is noticeably lower than it was on this vehicle at one time, as previously shown by an actual road test.

Poor Fuel Fill Quality:

Difficulty when refueling the vehicle.

Rough, Unstable, or Incorrect Idle and Stalling:

The engine runs unevenly at idle. If severe, the engine or the vehicle may shake. Engine idle may vary in speed. Either condition may be severe enough to stall the engine.

Surges/Chuggles:

Engine power variation under steady throttle or cruise. Feels like the vehicle speeds up and slows down with no change in the accelerator pedal position.

Symptoms Verification

Perform the Diagnostic System Check prior to using this diagnostic procedure. Verify that all of the following conditions are true:

The engine control module (ECM) and the malfunction indicator lamp (MIL) are operating correctly.
There are no DTCs stored.
The scan tool data is within the normal operating range.
Bulletins are not available for the current symptom.
The ECM grounds are clean, tight, and in the correct locations.
The vehicle tires are correctly inflated and meet original equipment specifications.
The air filter element is not restricted.

Symptoms Testing

Test for the following conditions:

The fuel system for the following:Correct fuel pressure—Refer to Fuel System Diagnosis.

Correct fuel pressure.
Fuel injectors that are leaking or improper operation.
Contaminated or a poor fuel quality condition.

The ignition system for the following:

Spark plugs for incorrect heat range or an abnormal condition.
For diagnosis of coolant or oil fouled spark plugs.
Wet down the secondary ignition system with water from a spray bottle. Wetting down the secondary ignition system may help locate damaged or deteriorated components. Look/listen for arcing or misfiring as the water is applied.
Weak spark.

The operation of the transmission torque converter clutch (TCC)—The scan tool should indicate an engine speed drop when the TCC is commanded ON.
The operation of the A/C compressor
Items that can cause an engine to run lean or rich—Refer to DTC P2178, 2180, P2188, or P2190.
The crankshaft position (CKP) sensor for the correct resistance—The CKP sensor resistance may be out of range after a hot soak. The resistance should be between 700–1200 ohms.
The engine for the following mechanical failures

Excessive oil in the combustion chamber or leaking valve seals
Incorrect cylinder compression
Sticking or leaking valves
Worn camshaft lobes
Incorrect valve timing
Broken valve springs
Excessive carbon buildup in the combustion chambers—Clean the chambers with top engine cleaner. Follow the instructions on the can.
Incorrect engine parts

Vacuum hoses for splits or kinks
Knock sensor (KS) system for excessive spark retard activity—Refer to Knock Sensor (KS) System Descriptionand DTC P0327, P0328, P0332, or P0333.
The exhaust system components for the following:

Physical damage or possible internal failure
The three-way catalytic converters for a restriction

Electromagnetic interference (EMI) on the reference circuit can cause a misfire condition. You can usually detect EMI with a scan tool by monitoring the engine speed parameter. A sudden increase in the engine speed parameter with little change in actual engine speed indicates that EMI is present. Inspect the high voltage components near the ignition control circuit if a condition exists.
Inspect the positive crankcase ventilation (PCV) system and all connections for leaks or restrictions.
Evaporative emission (EVAP) canister purge solenoid that is stuck open
The engine cooling system for the following conditions:

The thermostat is the correct heat range.
Proper engine coolant level.

If the above conditions do not address the symptom, refer to the additional symptoms tests.

Additional Symptoms Tests

Detonation/Spark Knock:

Test the engine for an overheating condition.

Poor Fuel Economy:

Inspect for foreign material accumulation in the throttle bore, and for carbon deposits on the throttle plate and shaft. Also inspect for throttle body tampering.

Rough, Unstable, or Incorrect Idle and Stalling:

Inspect the engine mounts.

Surges/Chuggles:

Test the heated oxygen sensors (HO2S). The HO2S should respond quickly to a change in throttle position. If the HO2S do not respond to different throttle positions, inspect for contamination from fuel, silicon, or the incorrect use of RTV sealant. The sensors may have a white powdery coating and result in a high, but false, signal voltage, which gives a rich exhaust indication. The ECM reduces the amount of fuel delivered to the engine, causing a driveability condition.

Hard Start:

Test the engine coolant temperature (ECT) sensor. Compare the ECT sensor value to the intake air temperature (IAT) sensor value on a cold engine. The ECT and IAT sensor values should be within ± 3°C (5°F). If the ECT sensor is out of range with the IAT sensor, test the resistance of the ECT sensor. Refer to Temperature vs Resistance - Engine Coolant Temperature (ECT) Sensor for resistance specifications. Replace the ECT sensor if the resistance is not within specification. If the sensor is within the specification, test the ECT circuits for a high resistance.
Test the fuel pump relay operation. The fuel pump should turn ON for 2 seconds when the ignition is turned ON.

Hesitation, Sag, Stumble:

Test the fuel pressure.
Test the generator.

Poor Fuel Economy:

Heavy loads being carried or towed
Acceleration rate too much or too often
Inspect for foreign material accumulation in the throttle bore, and for carbon deposits on the throttle plate and shaft. Also inspect for throttle body tampering.

Engine Cranks but Does Not Run

Diagnostic Fault Information

Circuit/System Description

This Engine Cranks but Does Not Run diagnostic is an organized approach to identify a condition which causes the engine to crank but not start. This diagnostic directs the technician to the appropriate system diagnosis.

Diagnostic Aids

Inspect for any of the following conditions:

The engine control module (ECM) uses the camshaft position (CMP) sensors to determine engine speed and position when there is a crankshaft position (CKP) sensor condition.
The engine will operate with a CKP sensor condition only if the ECM has stored the learned reference position of the camshafts in memory. With a CKP sensor condition in the signal circuit, the engine will go into a limp home mode aftera hard restart. The ECM then calculates engine speed from one of the CMP sensors. During a limp home mode, the following additional DTCs may set and should be ignored:

DTC P0324 Knock Sensor (KS) Module Performance
DTC P1011 Intake Camshaft Position Actuator Park Position Bank 1

Insufficient fuel can cause a no start condition. Thoroughly inspect the fuel delivery system for sufficient fuel volume to the fuel injectors. Inspect the fuel supply components for partial blockage or restrictions.Insufficient fuel can cause a no start condition. Thoroughly inspect the fuel delivery systemfor sufficient fuel volume to the fuel injectors. Inspect the fuel supply components for partial blockage or restrictions.
Fuel injectors with partially blocked and restricted nozzles, or a malfunctioning solenoid, can cause a no start condition.
There may be fuel spray at the fuel injectors and the indicated fuel pressure may be correct, yet there may not be enough fuel to start the engine. If the fuel injectors and the injector circuit are OK, and fuel spray is detected, the fuel injector ON time may be inadequate. If the engine control module (ECM) receives incorrect inputs from the various information sensors, the fuel delivered by the fuel injectors may be inadequate to start the engine. Check all the engine data parameters with a scan tool and compare the valuesindicated with the expected values or the values from a known good vehicle.
Check the crankshaft position (CKP) sensor engine reference signal with a scan tool. Observe the Engine Speed parameter while cranking the engine. The scan tool should indicate a steady 200–300 RPM while cranking. If erratic values,such as sudden spikes in the engine speed are displayed, the engine reference signal is not stable enough for the engine to start and run properly.
Inspect the engine for good secure electrical grounds.
If the engine almost starts and then stalls, check for an open in the ground circuits of the CKP sensor and the camshaft position (CMP) sensor.
Water or foreign material in the fuel can cause a no start or engine will not stay running condition. During freezing weather water can freeze inside the fuel system. The engine may start after 30 minutes in a heated repair shop. The malfunction may not recur until parked overnight in freezing temperatures. Extreme weather conditions can cause contaminated fuel to prevent the vehicle from starting.
A vehicle that starts and runs after being brought to the repair shop for a no start condition, may have an ignition system that is susceptible to moisture. Spray water on the ignition system components and the wiring in order to check for an engine starting or will not stay running concern.

An intermittent malfunction may be caused by fault in any of the critical information or component electrical circuits. Inspect the wiring harness and the components for an intermittent condition.

Circuit/System Verification

Attempt to start the engine. The engine should start and idle.
If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

Circuit/System Testing

Ignition ON, observe the DTC information with a scan tool. Verify that DTCs P0685, P0686, P0687, P0689, or P0690 are not set

If any of the listed DTCs are set, refer to DTC P0685, P0686, P0687, P0689, or P0690for further diagnosis.

Crank the engine for 15 seconds. Observe the DTC information with a scan tool. Verify that DTCs P0116, P0118, P0119, P0201-P0206, P0335, P0336, P0337, P0338, P0351-P0356, P0601, P0602, P0604, P0606, P0627, P0628, P0629, P1629, P1630, P1631, or P2105 do not set.

If any of the listed DTCs are set, refer to the appropriate DTC information.

Ignition ON, observe the Theft Deterrent parameter with a scan tool. The parameter should display Disabled.

If Enabled is displayed, refer to the appropriate DTC information.

Ignition ON, command the fuel pump ON with a scan tool. You should hear the fuel pumpturn ON.

If the fuel pump does not turn ON, refer to Fuel Pump Electrical Circuit Diagnosis.

Ignition OFF, install the fuel pressure gage.

Important :

The fuel pump may need to be commanded ON a few times, in order to obtain the highest possible fuel pressure.
Do NOT start the engine for this test.

Ignition ON, command the fuel pump ON with a scan tool. The fuel pressure should be between 380-410 kPa (55-60 psi).

If the fuel pressure is not within range, refer to Fuel System Diagnosis.

Verify that the following conditions do not exist:

Disconnect the MAF sensor. The engine control module (ECM) will ignore the MAF sensor and default to the calculated air flow

If disconnecting the MAF sensor corrects the condition and the connections are OK, replace the MAF sensor.

Collapsed air intake duct to the throttle body
Restricted air filter element
Spark plugs for being gas or coolant fouled
A skewed manifold absolute pressure (MAP) sensor
A skewed engine coolant temperature (ECT) sensor
Exhaust system restricted
Fuel contamination
Engine mechanical condition, for example, worn timing chain and gears, low compression

If you find any of the above conditions, repair as necessary.

Fuel Pump Electrical Circuit Diagnosis

Diagnostic Fault Information

Perform the Diagnostic System Check prior to using this diagnostic procedure.

Circuit/System Description

The engine control module (ECM) provides a ground to the coil side of the fuel pump relay. When the ignition switch is first turned ON, the ECM turns ON the fuel pump relay, which applies power to the fuel pump. The ECM enables the fuel pump relay as long as the engine is cranking or running, and crankshaft reference pulses are received. If no crankshaft reference pulses are received, the ECM turns OFF the fuel pump relay after about 3 seconds.

Diagnostic Aids

The following conditions may cause the fuel pump fuse to open:

The fuse is faulty.
There is an intermittent short to ground in the supply voltage circuit of the fuel pump.
The fuel pump has an intermittent internal condition.

Circuit/System Verification

Important : Fuel pump DTCs may set when using the Fuel Pump output control.

Ignition ON, command the fuel pump relay ON with a scan tool. You should hear the fuel pump operate for 3–5 seconds and then turn OFF.
If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

Circuit/System Testing

Ignition OFF, the fuel pump should not be operating.

If the fuel pump operates continuously, test for a short to voltage in supply voltage circuit of the fuel pump. If the circuit/connections test normal, replace the fuel pump relay.

Test the fuel pump fuse. The fuse should not be open.

If the fuel pump fuse is open, test for a short to ground in the supply voltage circuit of the fuel pump. If the circuit/connections test normal, replace the fuel pump.

Ignition OFF, remove the fuel pump relay from the electrical center.
Ignition ON, test for battery voltage between the B+ voltage circuit of the fuel pump relay and ground.

If less than B+, repair the B+ voltage circuit of the fuel pump relay for an open/high resistance.

Connect a 15-amp fused jumper wire between the B+ circuit of the fuel pump relay and the supply voltage circuit of the fuel pump. The fuel pump should operate.

If the fuel pump does not operate, test for the following conditions:

An open/high resistance in the supply voltage circuit of the fuel pump
An open/high resistance in the ground circuit of the fuel pump

If the above circuit/connections test normal, replace the fuel pump.

If all circuit/connections test normal, test or replace the fuel pump relay.

Component Testing

Measure for 70–110 ohms of resistance between terminals 85 and 86 of the fuel pump relay.

If the resistance is not within the specified range, replace the fuel pump relay.

Measure for infinite resistance between the following terminals of the fuel pump relay:

30 and 86
30 and 87
30 and 85
85 and 87

If continuity is detected, replace the fuel pump relay.

Connect a 20-amp fused jumper wire from the positive terminal of the battery to relay terminal 85. Connect a jumper wire from the negativeterminal of the battery to relay terminal 86. Measure for less than 2 ohms between terminals 30 and 87 of the relay.

If the resistance measures more than 2 ohms, replace the fuel pump relay.

Fuel System Diagnosis

Diagnostic Fault Information

Perform the Diagnostic System Check prior to using this diagnostic procedure.

Circuit/System Description

The control module enables the fuel pump relay when the ignition switch is turned ON. The control module will disable the fuel pump relay within 2 seconds unless the control module detects ignition reference pulses. The control module continues to enable the fuel pump relay as long as ignition reference pulses are detected. The control module disables the fuel pump relay within 2 seconds if ignition reference pulses cease to be detected and the ignition remains ON.

The fuel system is a returnless on-demand design. The fuel pressure regulator is a part of the primary fuel tank module, eliminating the need for a return pipe from the engine. A returnless fuel system reduces the internal temperature of the fuel tank by not returning hot fuel from the engine to the fuel tank. Reducing the internal temperature of the fuel tank results in lower evaporative emissions.

An electric turbine style fuel pump attaches to the primary fuel tank module inside the fuel tank. The fuel pump supplies high pressure fuel through the fuel filter, past the fuel pressure regulator, and through the fuel feed pipe to the fuel injection system. The fuel pressure regulator has a T-joint that diverts the needed fuel to the fuel rail with the unused fuel dropping back into the reservoir of the primary fuel tank module. The primary fuel tank module contains a reverse flow check valve. The check valve and the fuel pressure regulator maintain fuel pressure in the fuel feed pipe and the fuel rail in order to prevent long cranking times.

The primary fuel tank module also contains a primary jet pump and a secondary jet pump. Fuel pump flow loss, caused by vapor expulsion in the pump inlet chamber, is diverted to the primary jet pump and the secondary jet pump through a restrictive orifice located on the pump cover. The primary jet pump fills the reservoir of the primary fuel tank module. The secondary jet pump creates a venturi action which causes the fuel to be drawn from the secondary side of the fuel tank, through the fuel transfer pipe, to the primary side of the fuel tank.

Diagnostic Aids

A vehicle that runs out of fuel above empty may indicate a condition with the siphon jet pump, or transfer lines between the fuel tanks. Inspect for blockage, foreign objects or restrictions in all related hardware.
A vehicle that runs out of fuel above empty may be caused by an inaccurate fuel level sender. Inspect the float arm for binding, or obstructions.

Circuit/System Verification

Important :

Inspect the fuel system for damage or external leaks before proceeding.
Verify that adequate fuel is in the fuel tank before proceeding.
The fuel pump relay may need to be commanded ON a few times in order to obtain the highest possible fuel pressure.
DO NOT start the engine.

Ignition ON, command the fuel pump relay ON with a scan tool. You should hear the fuel pump turn ON and OFF for 3–5 seconds.

If the fuel pump does not operate, refer to Fuel Pump Electrical Circuit Diagnosis.

Ignition OFF, all accessories OFF, install the fuel pressure gage.
Ignition ON, command the fuel pump relay ON with a scan tool. Verify the fuel pressure is between 380-410 kPa (55-60 psi) and remains steady for 5 minutes.
Operate the vehicle within the conditions of the customers concern while monitoring fuel related parameters with a scan tool.

If the scan tool parameters do not indicate a lean condition, refer to Symptoms - Engine Controls.

Circuit/System Testing

Ignition ON, command the fuel pump relay ON with a scan tool and observe the fuel pressure while the fuel pump is operating. Verify the fuel pressure is between 380-410 kPa (55-60 psi).

If the fuel pressure is more than the specified range, replace the fuel pump.
If the fuel pressure is less than the specified range, remove the fuel tank and test/inspect for the following:

Restricted fuel feed pipe
Restricted or plugged fuel filter
Restricted or plugged strainer
Stuck or binding fuel level float
Restricted siphon jet pump
Restricted transfer lines between fuel tanks
Faulty fuel pressure regulator
Poor connections at the harness connectors and ground circuits of the fuel pump

If you find a condition, repair as necessary.
If all components test normal, replace the fuel pump.

Important : The fuel pressure may vary slightly when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant.

Verify that the fuel pressure does not decrease more than 34 kPa (5 psi) in 1 minute.

If the fuel pressure decreases more than the specified value, perform the following procedure:

Ignition OFF, relieve the fuel pressure.
Install the fuel pressure gage.
Verify that the fuel pressure does not decrease more than 34 kPa (5 psi) in 1 minute.

If the fuel pressure remains constant, replace the fuel pump.
If the fuel pressure drops, locate and replace the leaking fuel injector.

Relieve the fuel pressure to 69 kPa (10 psi). Verify that the fuel pressure does not decrease more than 14 kPa (2 psi) in 5 minutes.

If the fuel pressure decreases more than the specified value, replace the fuel pump.

Remove the fuel pressure gage.
Operate the vehicle within the conditions of the customer concern while monitoring fuel related parameters with a scan tool.

If the scan tool parameters indicate a lean condition, test/inspect for the following:

Restricted fuel feed pipe
Restricted fuel filter
Restricted siphon jet pump
Restricted transfer lines between fuel tanks
Faulty fuel pressure regulator
Poor connections at the harness connectors and ground circuits of the fuel pump

If all component test normal and the scan tool paramenters indicates a lean condition, replace the fuel pump.

Fuel Injector Coil Test

Diagnostic Fault Information

Perform the Diagnostic System Check prior to using this diagnostic procedure.

Circuit/System Description

The control module enables the appropriate fuel injector pulse for each cylinder. The ignition voltage is supplied directly to the fuel injectors. The control module controls each fuel injector by grounding the control circuit via a solid state device called a driver. A fuel injector coil winding resistance that is too high or too low will affect the engine driveability. A fuel injector control circuit DTC may not set, but a misfire may be apparent. The fuel injector coil windings are affected by temperature. The resistance of the fuel injector coil windings will increase as the temperature of the fuel injector increases.

Diagnostic Aids

Monitoring the misfire current counters, or misfire graph, may help to isolate the fuel injector that is causing the condition.
Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition.
Perform the fuel injector coil test within the conditions of the customers concern. A fuel injector condition may only be apparent at a certain temperature, or under certain conditions.

Component Testing

Verify the resistance of each fuel injector with one of the following methods:

If the engine coolant temperature (ECT) sensor is between 10–32°C (50–90°F), the resistance of each fuel injector should be 11–14 ohms.

If the resistance of any fuel injector is not 11–14 ohms, replace the fuel injector.

If the ECT sensor is not between 10–32°C (50–90°F), measure and record the resistance of each fuel injector with a DMM. Subtract the lowest resistance value from the highest resistance value. The difference between the lowest value and the highest value should be equal to or less than 3 ohms.

If the difference is equal to or less than 3 ohms, refer to Fuel Injector Balance Test for further diagnosis of the fuel injectors.
If the difference is more than 3 ohms, add all of the fuel injector resistance values to obtain a total resistance value. Divide the total resistance value by the number of fuel injectors to obtain an average resistance value. Subtract the lowest, and the highest, individual fuel injector resistance values from the average resistance value. Replace the fuel injector that displays the greatest resistance difference above or below the average.

Fuel Injector Balance Test

Diagnostic Fault Information

Perform the Diagnostic System Check prior to using this diagnostic procedure.

Fuel Injector Balance Test Example

Cylinder	1	2	3	4	5	6
First Reading	360 kPa (52 psi)	360 kPa (52 psi)	360 kPa (52 psi)	360 kPa (52 psi)	360 kPa (52 psi)	360 kPa (52 psi)
Second Reading	195 kPa (28 psi)	138 kPa (20 psi)	195 kPa (28 psi)	195 kPa (28 psi)	235 kPa (34 psi)	195 kPa (28 psi)
Amount Of Drop	166 kPa (24 psi)	222 kPa (32 psi)	166 kPa (24 psi)	166 kPa (24 psi)	125 kPa (18 psi)	166 kPa (24 psi)
Average Range: 156–176 kPa (22.5–25.5 psi)	Injector OK	Fuel Injector – Too Much Pressure Drop	Injector OK	Injector OK	Faulty Injector – Too Little Pressure Drop	Injector OK

Circuit/System Description

The scan tool is first used to energize the fuel pump relay. The fuel injector tester is then used to pulse each injector for a precise amount of time, allowing a measured amount of fuel into the manifold. This causes a drop in system fuel pressure that can be recorded and used to compare each injector.

Diagnostic Aids

Monitoring the misfire current counters, or misfire graph, may help to isolate the fuel injector that is causing the condition.
Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition.
Perform the fuel injector balance test within the conditions of the customers concern. A fuel injector condition may only be apparent at a certain temperature, or under certain conditions.

Component Testing

Fuel Injector Balance Test

Ignition ON, with a scan tool verify that the engine coolant temperature (ECT) is less than 94°C (201°F).

If the ECT is greater than 94°C (201°F) allow the engine to cool before proceeding.

Ignition OFF, install the fuel pressure gage.
Ignition ON, verify the fuel pressure is within 380-410 kPa (55-60 psi).

If the fuel pressure is not within the specified range refer to Fuel System Diagnosis for further diagnosis of the fuel system.

Monitor the fuel pressure gage for 1 minute. Verify that the fuel pressure does not drop more than 34 kPa (5 psi).

If the fuel pressure decreases more than 34 kPa (5 psi) refer to Fuel System Diagnosis for further diagnosis of the fuel system.

Notice : Do Not repeat any portion of this test before running the engine in order to prevent the engine from flooding.

Connect the fuel injector tester to a fuel injector with the amperage supply selector switch on the fuel injector tester to the Balance Test 0.5–2.5 amp position.
Command the fuel pump relay ON with a scan tool and record the fuel pressure indicated by the fuel pressure gage after the fuel pressure stabilizes. This is the first pressure reading.

Important :

Repeat this step for each fuel injector in order to obtain a pressure drop value for each fuel injector.
The fuel pressure may rise after the fuel injector stops pulsing. Record the fuel pressure value immediately after the fuel injector stops pulsing. DO NOT record the higher fuel pressure value.

Energize the fuel injector by depressing the Push to Start Test button on the fuel injector tester. Record the fuel pressure indicated by the fuel pressure gage after the fuel injector has stopped pulsing. This is the second pressure reading.
Add all of the individual pressure drop values in order to calculate the total pressure drop. Divide the total pressure drop by the number of fuel injectors in order to calculate the average pressure drop. The difference between any individual pressure drop and the average pressure drop should not be more than 20 kPa (3 psi).

If the difference between any individual pressure drop and the average pressure drop is more than 20 kPa (3 psi), replace the fuel injector.

Fuel Tank Leak Test

Caution : Place a dry chemical (Class B) fire extinguisher near the area before performing a Fuel Tank Leak Check. Before removing the fuel tank for a suspected leak, make sure that the fuel pipes or the tubes are not leaking onto the tank. Once removed, make sure that the fuel is not leaking around the fuel sender O-ring. Failure to follow these precautions may result in personal injury.

Diagnostic Fault Information

Always perform the Diagnostic System Check prior to using this diagnostic procedure.

Circuit/System Description

The fuel tank leak test is used to locate any fuel or fuel vapor escaping the fuel tank area. Fuel vapors escaping above the fuel level will be detected when the evaporative emission (EVAP) leak diagnostic completes one test cycle. The malfunction indicator lamp (MIL) will illuminate after the EVAP leak diagnostic completes 2 test cycles for a large leak or up to 8 test cycles for a small leak, only when a condition is detected.

Diagnostic Aids

Operate the vehicle under the condition of the customer concern. Under high temperature conditions fuel vapors may increase to the point of EVAP canister vapor saturation. Fuel vapors would then be released into the atmosphere. Once the engine is running and the EVAP purge is enabled, all fuel vapor release would be eliminated.
Movement of the EVAP pipes or the fuel pipes may help find an intermittent condition.
If the fuel level is low, a liquid fuel leak may not be evident.

Circuit/System Verification

Verify that the fuel tank and the fuel pipes are not damage or leaking.

If you located a condition, repair as necessary.

Ignition ON, command the fuel pump relay ON with a scan tool. Verify that the fuel pipes are not leaking.

If you located a condition, repair as necessary.

Important : Refer to the J 41413-200 Evaporative Emissions System Tester (EEST) operation manual for detailed instructions.

Ignition OFF, install the J 41413-200and the GE-41415-50to the fuel filler pipe.
Command the EVAP vent solenoid closed with a scan tool.
Turn the nitrogen/smoke valve to Nitrogen and verify that there is no liquid fuel leak while the system is under pressure.

If a leak is located, repair as necessary.

Important : It may be necessary to partially lower the fuel tank.

Using the J 41413-200 introduce smoke into the EVAP system. Verify that there are no vapor leaks in any of the following locations:

The fuel tank, the fill limiter vent valve, the pressure relief valve, and the grade vent valves
The fuel sender housing, the fuel sender seal, the fuel pipe, and the EVAP pipes
The fuel tank pressure (FTP) sensor seal
The fuel fill pipe and hose

If a leak is observed, repair as necessary.

Component Testing

Fuel Injector Balance Test

Ignition ON, with a scan tool verify that the engine coolant temperature (ECT) is less than 94°C (201°F).

If the ECT is greater than 94°C (201°F) allow the engine to cool before proceeding.

Ignition OFF, install the fuel pressure gage.
Ignition ON, verify the fuel pressure is within 380-410 kPa (55-60 psi).

If the fuel pressure is not within the specified range refer to Fuel System Diagnosis for further diagnosis of the fuel system.

Monitor the fuel pressure gage for 1 minute. Verify that the fuel pressure does not drop more than 34 kPa (5 psi).

If the fuel pressure decreases more than 34 kPa (5 psi) refer to Fuel System Diagnosis for further diagnosis of the fuel system.

Notice : Do Not repeat any portion of this test before running the engine in order to prevent the engine from flooding.

Connect the fuel injector tester to a fuel injector with the amperage supply selector switch on the fuel injector tester to the Balance Test 0.5–2.5 amp position.
Command the fuel pump relay ON with a scan tool and record the fuel pressure indicated by the fuel pressure gage after the fuel pressure stabilizes. This is the first pressure reading.

Important :

Repeat this step for each fuel injector in order to obtain a pressure drop value for each fuel injector.
The fuel pressure may rise after the fuel injector stops pulsing. Record the fuel pressure value immediately after the fuel injector stops pulsing. DO NOT record the higher fuel pressure value.

Energize the fuel injector by depressing the Push to Start Test button on the fuel injector tester. Record the fuel pressure indicated by the fuel pressure gage after the fuel injector has stopped pulsing. This is the second pressure reading.
Add all of the individual pressure drop values in order to calculate the total pressure drop. Divide the total pressure drop by the number of fuel injectors in order to calculate the average pressure drop. The difference between any individual pressure drop and the average pressure drop should not be more than 20 kPa (3 psi).

If the difference between any individual pressure drop and the average pressure drop is more than 20 kPa (3 psi), replace the fuel injector.

Intake Manifold Runner Control System Diagnosis

Diagnostic Fault Information

Perform the Diagnostic System Check prior to using this diagnostic procedure.

Circuit/System Description

An intake manifold runner control (IMRC) valve is used to change the intake manifold plenum configuration. When the IMRC valve is open, the intake manifold is configured to one large plenum.

When the IMRC valve is closed, the intake manifold is configured to 2 smaller plenums. The IMRC valve improves engine performance at low and high engine speeds.

Ignition voltage is supplied directly to the IMRC solenoid. The engine control module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driveris equipped with a feedback circuit that is pulled up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

Diagnostic Aids

Inspect the IMRC solenoid valve for witness marks that indicate that the valve was hitting the intake manifold. This condition may be temperature related.

Circuit/System Verification

Ignition ON, observe the DTC information with a scan tool. Verify that DTCs P2008, P2009, or P2010 are not set.

If any of the DTCs listed are set, refer to the appropriate DTC information for further diagnosis.

Circuit/System Testing

Ignition OFF, remove the intake manifold runner control (IMRC) solenoid from the intake manifold, with the electrical connector connected.
Ignition ON, command the IMRC solenoid ON and OFF with a scan tool. Verify that the IMRC solenoid operates in both directions.

If the IMRC solenoid does not operate in both directions, replace the IMRC solenoid.

Inspect the inside of the intake manifold for the following conditions:

Carbon build-up that limits the movement of the IMRC valve
Casting flash that limits the movement of the IMRC valve
Foreign material that limits the movement of the IMRC valve

If a condition is found, repair as necessary.

Clean or replace the upper intake manifold.

Electronic Ignition (EI) System Diagnosis

Diagnostic Fault Information

Perform the Diagnostic System Check prior to using this diagnostic procedure.

Circuit/System Description

Ignition 1 voltage is supplied to the ignition coils. The engine control module (ECM) provides a ground for the ignition coil (IC) control circuits. When the ECM removes the ground path of the ignition primary coil, the magnetic field produced by the coil collapses. The collapsing magnetic field produces a voltage in the secondary coil which ignites the spark plugs. The sequencing and timing are controlled by the ECM.

Diagnostic Aids

The ignition coils for each bank are fused separately. If a fuse opens or the ignition 1 voltage circuit opens between the fuse and the splice, all the ignition coils for one bank of the engine would be inoperative. If the ground circuit opens at the engine block, the ignition coils would be inoperative for one bank of the engine.
Inspect the ignition coils for aftermarket devices. An aftermarket device connected to the ignition coil circuits, may cause a condition with the ignition coils.

Circuit/System Testing

Important : Do not perform this diagnostic procedure if you were not sent here from a misfire DTC or the Engine Cranks but Does Not Run diagnostic.

Ignition OFF, disconnect the harness connector of the ignition coil.
Ignition ON, load test for battery voltage between the ignition 1 voltage circuit of the ignition coil and ground.

If less than B+, repair the ignition 1 voltage circuit of the ignition coil for a short to ground or an open/high resistance.

Ignition OFF, test for less than 5 Ohms of resistance between the ground circuit of the ignition coil and the negative terminal of the battery.

If greater than 5 Ohms, repair the ground circuit of the ignition coil for an open/high resistance.

If all circuits/connections test normal, replace the ignition coil.