Orlando |
||||||||
|
|
|
|||||||
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
The engine control module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during open loop and closed loop. During open loop, the ECM determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S) input. During closed loop, the ECM adds HO2S inputs and level of purge to calculate the short and long term fuel trim adjustments. If the HO2S indicates a lean condition, the fuel trim values will be above 0%. If the HO2S indicates a rich condition, the fuel trim values will be below 0%. The short term fuel trim values change rapidly in response to the HO2S voltage signals. The long term fuel trim makes rough adjustments in order to maintain an optimal air/fuel ratio. A block of memory cells contains information arranged in combinations of engine speed and engine load for a full range of vehicle operating conditions. The long term fuel trim diagnostic is based on an average of cells currently being used. The ECM selects the cells based on engine speed and load. The fuel trim diagnostic will conduct a test to determine if a rich failure actually exists or if more vapour than the customer may desire from the evaporative emission (EVAP) canister is causing a rich condition.
The heating elements inside each heated oxygen sensor (HO2S) heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter closed loop earlier and the control module to calculate the air-to-fuel ratio sooner.
The heated oxygen sensor (HO2S) utilises the following circuits:
| • | A signal circuit |
| • | A low reference circuit |
| • | An ignition voltage circuit |
| • | A heater control circuit |
| • | DTCs P0030 00, P0031 00, P0032 00, P0107 00, P0108 00, P0112 00, P0113 00, P0121 00, P0122 00, P0123 00, P0128 00, P0131 00, P0132 00, P0133 00, P0134 00, P0135 00, P0137 00, P0138 00, P0140 00, P0141 00, P0201 00 - P0204 00, P0220 00, P0222 00, P0223 00, P0300 00 - P0304 00, P0442 00, P0443 00, P0446 00, P0451 00, P0452 00, P0453 00, P0454 00, P0455 00, P0461 00, P0462 00, P0463 00, P0496 00, P0506 00, P0507 00, P2101 00, P2119 00, P2122 00, P2123 00, P2127 00, P2128 00, P2138 00, P2176 00, P2A00 00 are not set. |
| • | Where applicable DTCs P2270 00, P2271 00, P2272 00, P2A01 00 are not set. |
| • | The loop status parameter indicates closed. |
| • | The fuel trim learn is enabled. |
| • | The engine coolant temperature (ECT) is between -38 to +150°C (-36.4 to +302°F). |
| • | The intake air temperature (IAT) is between -38 to +150°C (-36.4 to +302°F). |
| • | The manifold absolute pressure (MAP) is between 5-255 kPa (0.73-37 psi). |
| • | The vehicle speed is less than 134 km/h (83 MPH). |
| • | The engine speed is between 400-6 000 RPM. |
| • | The barometric pressure (BARO) is more than 70 kPa (10 PSI). |
| • | DTCs P0171 00 and P2096 00 run continuously when the above conditions have been met. |
| • | DTCsP000A 00, P000B 00, P0010 00, P0011 00, P0013 00, P0016 00, P0017 00, P0030 00, P0031 00, P0032 00, P0106 00, P0107 00, P0108 00, P0117 00, P0118 00, P0119 00, P0121 00, P0122 00, P0123 00, P0131 00, P0132 00, P0133 00, P0137 00, P0138 00, P0139 00, P0140 00, P0141 00, P0171 00, P0172 00, P0201 00, P0202 00, P0203 00, P0204 00, P0221 00, P0222 00, P0223 00, P0261 00, P0262 00, P0264 00, P0265 00, P0267 00, P0268 00, P0270 00, P0271 00, P0300 00, P0301 00, P0302 00, P0303 00, P0304 00, P0313 00, P0335 00, P0336 00, P0340 00, P0341 00, P0365 00, P0366 00, P0420 00, P0443 00, P0458 00, P0459 00, P1106 00, P2088 00, P2089 00, P2090 00, P2091 00, P2100 00, P2101 00, P2176 00, P2270 00, P2271 00, P2297 00, P2300 00, P2301 00, P2303 00, P2304 00, P2306 00, P2307 00, P2309 00, P2310 00, P2A00 00, P2A01 00 are not set. |
| • | The ignition is ON. |
| • | The evaporative emission (EVAP) system is not purging. |
| • | The post catalyst fuel trim is enabled. |
| • | These DTCs run continuously when the above conditions have been met. |
| • | The long term fuel trim weighted average value is more or less than a calibrated value. |
| • | The above condition is present for approximately 3 min after the conditions for running the DTC have been met. |
| • | Long term fuel trim adjustment has reached its limit while the sensor voltage is still trying to move the adjustment further in the same direction. |
| • | The above condition is present for approximately 3 min after the conditions for running the DTC have been met. |
DTCs P017 001, P2096 00 are type B DTCs.
DTCs P0171 00, P2096 00 are type B DTCs.
| • | On vehicles equipped with a vacuum brake booster, rapid brake pedal cycling may imitate a vacuum leak. |
| • | A failed HO2S will not cause DTC P2096 00 to set without the occurrence of circuit related HO2S DTCs. Do not replace an HO2S to address this DTC. |
| • | An exhaust system leak that may not be audible can set these DTCs. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
Note: Disregard any transmission symptoms, antilock brake system (ABS) indicators, and traction control system indicators until any fuel trim faults are repaired. A fuel trim fault may cause default actions such as harsh shifts and illumination of the ABS/traction control system indicators.
| ⇒ | If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle . |
| ⇒ | If the value does not vary from approximately 40 mV to approximately 900 mV, refer to DTC P0137-P0140, P2270, P2271, or P2A01 . |
Note: The EVAP purge enablement may cause the fuel trim to be momentarily outside the normal range
Note: Allow the engine to reach operating temperature. With the engine running, observe the Long Term Fuel Trim parameter with a scan tool. The value should be less than approximately 18% with the engine running at operating temperature.
| ⇒ | If the value is not less than 18%, inspect for the following: |
| • | With the ignition ON and the engine OFF, observe the scan tool MAP Sensor parameter. The scan tool MAP Sensor pressure reading should be within the range specified for your altitude. Refer to Altitude Versus Barometric Pressure . |
| ⇒ | If the B74 Manifold Absolute Pressure Sensor does not indicate the correct barometric pressure, refer to DTC P0106, P0107, or P0108 . |
| • | With the engine idling and the transmission in the park or neutral position, observe the scan tool MAP Sensor parameter. The scan tool MAP Sensor parameter should be between 19-42 kPa (2.8-6.1 PSI). |
| ⇒ | If the scan tool MAP sensor parameter is not between 19-42 kPa (2.8-6.1 PSI), refer to DTC P0106, P0107, or P0108 . |
| • | Vacuum hoses for splits, kinks, and improper connections |
| • | Insufficient amount of fuel in the tank |
| • | Low fuel pressure. Refer to Fuel System Diagnosis . |
| • | Fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis . |
| • | Malfunctioning fuel injectors. Refer to Fuel Injector Diagnosis : Scan Tool → Special Tool . |
| • | Missing, loose, or leaking exhaust components from the HO2S forward. Refer to Symptoms - Engine Exhaust . |
| • | Vacuum leaks at the intake manifold, the throttle body, the brake booster hose, and the injector O-rings |
| • | The air induction system and the air inlet ducts for leaks or for a missing air filter element |
| • | A cracked EVAP canister |
| • | Evaporative pipes obstructed or leaking |
| • | The crankcase ventilation system for leaks. Refer to Crankcase Ventilation System Inspection/Diagnosis : LDE, LED, LFJ, LXV, 2H0, LUW, LFH . |
| • | The HO2S for improper installation and for electrical wires or connectors that may have contacted the exhaust system |
| • | The B52A Heated Oxygen Sensor 1 sensor 1 signal circuit open, shorted to ground, or shorted to the low reference circuit |
| • | The B52A Heated Oxygen Sensor 1 sensor 1 low signal circuit for an open circuit or high resistance |
| • | Malfunctioning engine components. Refer to Symptoms - Engine Mechanical . |
Repair or replace as necessary.
| • | Air Cleaner Assembly Replacement : LDE, LXV, LUW, 2H0 and LFH |
| • | Air Cleaner Element Replacement : 1.6L LDE, LXV, 1.8L 2H0, LUW and LFH |
| • | Heated Oxygen Sensor Replacement - Sensor 1 : LDE, LXV, LUW, 2H0 |
| • | Manifold Absolute Pressure Sensor Replacement : 1.8L 2H0 and LUW |
| • | Throttle Body Assembly Replacement : 1.6L LDE, LXV, 1.8L 2H0, and LUW |
Note: After repairs, use the scan tool fuel trim reset function in order to reset the long term fuel trim values.
Note: Do not clear codes with the engine running. DTCs may reset in the same ignition cycle.
| © Copyright Chevrolet. All rights reserved |
