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| Table 1: | Engine Control Module Scan Tool Data Parameters |
| Table 2: | Engine Control Module Scan Tool Output Controls |
Engine Control Module Scan Tool Data Parameters
Engine Control Module Scan Tool Output Controls
The Engine Control Module Scan Tool Data List contains all engine related parameters that are available on the scan tool. The list is arranged in alphabetical order. A given parameter may appear in any one of the data lists, and in some cases may appear more than once, or in more than one data list in order to group certain related parameters together.
Use the Engine Scan Tool Data List only after the following is determined:
| • | The Diagnostic System Check - Vehicle is completed. |
| • | No diagnostic trouble codes (DTCs) are set. |
| • | On-board diagnostics are functioning properly. |
The scan tool values from a properly running engine may be used for comparison with the engine you are diagnosing. The Engine Scan Tool Data List represents values that would be seen on a normally running engine.
Note: A scan tool that displays faulty data should not be used. The scan tool concern should be reported to the manufacturer. Use of a faulty scan tool can result in misdiagnosis and unnecessary parts replacement.
Only the parameters listed below are referenced in this service manual for use in diagnosis. If all values are within the typical range described below, refer to Symptoms - Engine Controls for engine diagnosis.
Parameter | System State | Expected Value | Description |
|---|---|---|---|
Operating Conditions: Engine Idling/Radiator Hose Hot/Closed Throttle/Park or Neutral/Closed Loop/Accessories Off/Brake Pedal Released | |||
A/C High Side Pressure Sensor | A/C OFF | 0.75-1.5 V | This parameter displays the voltage from the A/C high side pressure sensor signal circuit to the control module. *Varies with temperature and relative humidity. |
A/C ON | 1.3-2.5 V | ||
A/C High Side Pressure Sensor | A/C OFF | 450-650 kPa (65-95 psi) | This parameter displays the pressure from the A/C high side pressure sensor signal circuit to the control module. *Varies with temperature and relative humidity. |
Engine Speed at 2,000 RPM | 1117-2350 kPa (162-341 psi) | ||
A/C Relay Command | A/C ON | On | This parameter displays the state of the air conditioning (A/C) clutch relay control circuit as commanded by the control module. |
Actual IAC Position | - | 10-40 counts | This parameter displays the engine control module (ECM) command for the IAC pintle position in counts. The higher the number of counts, the greater the commanded idle speed reads. The IAC responds to changes in the engine load in order to maintain the desired idling speed. |
BARO | - | 65-104 kPa (8-16 psi) Varies with altitude | This parameter displays the barometric pressure (BARO). The control module uses the barometric pressure sensor input for fuel control to compensate for altitude differences. |
Desired IAC Position | - | 10-40 counts | This parameter displays the desired IAC pintle position in counts. The IAC responds to changes in the engine load in order to maintain the desired idling speed. |
Desired Idle Speed | - | 600-950 RPM | This parameter displays the desired engine idle speed as commanded by the control module. |
Distance after MIL ON | -- | Varies | This parameter displays the mileage that has elapsed since the MIL is illuminated. |
EC Ignition Relay Command | Ignition ON | ON | This parameter displays the state of the control circuit for main relay as commanded by the control module. |
ECT Sensor | - | 0-5 V | This parameter displays the voltage of the engine coolant based on input to the control module from the engine coolant temperature (ECT) sensor. |
ECT1 Sensor | - | -48 to +142.5°C (-54.4 to +288.5°F) Varies | This parameter displays the temperature of the engine coolant based on input to the control module from the engine coolant temperature (ECT) sensor 1. |
ECT2 Sensor | - | -48 to +142.5°C (-54.4 to +288.5°F) Varies | This parameter displays the temperature of the radiator coolant based on input to the control module from the radiator coolant temperature (ECT) sensor 2. |
EGR Position Sensor | - | 0.6-0.75 V | This parameter displays the actual EGR pintle position in volts. |
EGR Solenoid Command | - | 0% | This parameter displays the state of the control circuit for EGR solenoid as commanded by the control module. |
Engine Load | - | Partial | This parameter displays the state of the current engine load. |
Engine Run Time | -- | Varies | This parameter displays the time elapsed since the engine was started. |
Engine Speed | -- | 600-950 RPM | This parameter displays the speed of the engine crankshaft rotation from information received from the crankshaft position sensor. |
EVAP Purge Solenoid Command | - | 10-20% | This parameter displays the on-time or duty cycle of the evaporative emission (EVAP) canister purge solenoid commanded by the control module. Zero percent indicates no purge. One hundred percent indicates full purge. |
Evaporator Temperature | -- | Varies | This parameter displays the voltage from the A/C evaporator temperature sensor signal circuit. |
Evaporator Temperature | - | -48 to +142.5°C (-54.4 to +288.5°F) | This parameter displays the temperature of the A/C evaporator core based on the input to the control module from the A/C evaporator temperature sensor signal circuit. |
FC Relay 1 Command | Fan Low Commanded ON | ON | This parameter displays the control module commanded state of the fan relay control circuit. |
FC Relay 2 Command | Fan High Commanded ON | ON | This parameter displays the control module commanded state of the fan relay control circuit. |
Fuel Level Sensor | -- | Varies | This parameter displays the approximate fuel level in the fuel tank as a voltage. The scan tool will display a low reading when the fuel level in the tank is near empty. The scan tool will display a high reading when the fuel level in the tank is high or near full. |
Fuel Level Sensor | -- | Varies | This parameter displays the approximate fuel level in the fuel tank as a percentage. The control module calculates this level using the signal from the sensor used to monitor the fuel in the tank. The scan tool will display a low reading when the fuel level in the tank is near empty. The scan tool will display a high reading when the fuel level in the tank is high or near full. |
Fuel Pump Relay Command | Ignition ON, engine OFF | Fuel pump on for 2 s | This parameter displays the control modules commanded state of the fuel pump relay control circuit. |
Engine idling | On | ||
Fuel Tank Pressure Sensor | - | 0.0 kPa | This parameter displays the pressure/vacuum inside the fuel tank. A negative value indicates a vacuum, while a positive value indicates a pressure. |
Fuel Tank Pressure Sensor | - | 1.3-1.7 V | This parameter displays the voltage signal received by the control module from the fuel tank pressure sensor. |
HO2S 1 or HO2S 2 | Ignition ON, Engine OFF | 400-500 mV | This parameter indicates the heated oxygen sensor (HO2S) sensor 1 or 2, output voltage as measured by the control module. The scan tool will display a higher value during a rich condition, and a lower value during a lean condition. |
Engine running | Varies | ||
HO2S 1 or HO2S 2 Heater Command | - | 0-99% | This parameter displays the commanded state of the HO2S 1 or HO2S 2 heater by the control module. The scan tool will display a higher value as the heater command is increased, and a lower value if the heater is not commanded ON. |
IAT Sensor | - | 0-5 V | This parameter displays the voltage measured by the control module from the intake air temperature sensor. |
IAT Sensor | - | -48 to +142.5°C (-54.4 to +288.5°F) | This parameter displays the temperature of the air entering the air induction system based on input to the control module from the intake air temperature (IAT) sensor. |
Ignition 1 Signal | - | B+ | This parameter displays B+ when the control module detects a voltage at the ignition input terminal. |
Ignition Timing | - | 2-10 Degrees | This parameter displays the amount of spark advance the control module is commanding on the ignition control circuits. The control module determines the desired advance. |
Knock Sensor | -- | Varies | This parameter displays the voltage input to the control module from the knock sensor (KS). |
Long Term FT | Engine Idling | 0% | This parameter displays the commanded Long Term Fuel Trim correction by the control module. |
Loop Status | - | Closed Loop | This parameter displays the state of the fuel control system as commanded by the control module. Closed Loop operation indicates that the control module is controlling the fuel delivery based on the oxygen sensors input signal. In Open Loop operation the control module ignores the oxygen sensor input signal and bases the amount of fuel to be delivered on other sensor inputs. |
MAF Sensor | -- | Varies | This parameter indicates the quantity of the air into the cylinder calculated by the control module based on a signal from the manifold absolute pressure (MAP) sensor. The scan tool will display a high value at high engine speeds, and a low value at low engine speeds. |
MAP Sensor | - | 26-52 kPa | This parameter displays the pressure from the manifold absolute pressure (MAP) sensor to the control module. |
MAP Sensor | - | 1.0-2.0 V | This parameter displays the signal voltage from the MAP sensor to the control module. |
PNP Switch | - | Park/Neutral | This parameter displays the position of the transmission selection as Park/Neutral or in gear. |
Short Term FT | - | -5% to +5% | This parameter displays the short-term correction to the fuel delivery by the control module in response to oxygen sensor. If the oxygen sensor indicates a lean air/fuel mixture, the control module will add fuel increasing the short term fuel trim above 0. If the oxygen sensor indicates a rich air/fuel mixture, the control module will reduce fuel decreasing the short term fuel trim below 0. |
TP Sensor | Accelerator pedal not actuated | 0.4-0.8 V | This parameter displays the voltage signal sent to the control module from throttle position sensor. The TP Sensor is a range of values indicating a high voltage when the throttle is closed to a low voltage when the throttle plate is fully open. |
Accelerator pedal fully actuated | 4.4-4.8 V | ||
TP Sensor | - | 0.2-0.6° | This parameter displays the actual throttle position angle indicated by the control module using information from the two throttle position sensors. |
Vehicle Speed Sensor | -- | 0 km/h (0 MPH) | This parameter displays the speed of the vehicle as calculated by the transmission control module (TCM) from information received from the vehicle speed sensor (VSS). |
Wheel Speed Sensor | -- | 0 km/h (0 MPH) | This parameter displays the speed of the wheel as calculated by the ECM based on information received from the wheel speed sensor. |
Output Control | Description |
|---|---|
A/C Relay | This function controls the A/C compressor relay. When commanded ON, the A/C compressor will cycle ON/OFF for 3-5 seconds. |
ECM Reset | This function resets all the values learned by the engine control module (ECM). |
EGR Solenoid |
Note: This function is only allowed with the ignition ON, engine OFF. This function controls the exhaust gas recirculation (EGR) solenoid. When commanded ON, the EGR solenoid will cycle from 0-100 percent for 3-5 seconds. This output can also be monitored on the scan tool by observing the EGR Position Sensor data parameter. |
Engine Controls Ignition Relay |
Note: This function is only allowed with the ignition ON, engine OFF. This function controls the engine control ignition relay or MAIN relay. When commanded ON, the engine control ignition relay will cycle ON/OFF for 3-5 seconds. |
EVAP Purge Solenoid | This function controls the evaporative emission (EVAP) purge solenoid. When commanded ON, the EVAP purge solenoid will cycle ON/OFF for 3-5 seconds. |
EVAP Test | Activates the on-board EVAP diagnostic test. |
EVAP Vent Solenoid Valve | This function controls the evaporative emission (EVAP) vent solenoid. When commanded ON, the EVAP vent solenoid will cycle ON/OFF for 3-5 seconds. |
Fan Relay 1 | This function controls the low speed cooling fan relay. When commanded ON, the cooling fan will turn ON at low speed for 5 seconds. |
Fan Relay 2 | This function controls the high speed cooling fan relay. When commanded ON, the cooling fan will turn ON at high speed for 5 seconds. |
Fuel Pump Relay |
Note: This function is only allowed with the ignition ON, engine OFF. This function controls the fuel pump relay. When commanded ON, the fuel pump relay will cycle ON/OFF for 3-5 seconds. |
Idle Learn Reset | This function resets the base idle value learned by the engine control module (ECM). |
ISC Actuator |
Note: This function is only allowed with the ignition ON, engine OFF. This function controls the idle speed control (ISC) actuator. The ECM actuates the ISC actuator for 3-5 seconds when commanded ON. |
Malfunction Indicator Lamp (MIL) | This function controls the malfunction indicator lamp (MIL). When commanded ON or OFF, the ECM turns the malfunction indicator lamp (MIL) ON or OFF. |
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