Diagnostic Starting Point - Engine Controls
Begin the system diagnosis with Diagnostic System Check - Vehicle in Vehicle DTC Information. The Diagnostic System Check-Vehicle will provide the following information
- The identification of the control modules which command the system
- The ability of the control modules to communicate through the serial data circuit
- The identification of any stored diagnostic trouble codes (DTCs) and the codes' statuses
The use of the Diagnostic System Check-Vehicle will identify the correct procedure for diagnosing the system and where the procedure is located.
Scan Tool Data List
The Engine 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 is completed
- No diagnostic trouble codes (DTCs).
- 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.
| IMPORTANT | 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 information for use in diagnosis. If all values are within the typical range described below, refer to SYMPTOMS - ENGINE CONTROLS for diagnosis.
The column labeled Data List indicates where a parameter can be located on the scan tool. Refer to the scan tool operating manual for the exact locations of the data lists. The following is a description of each term listed
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Engine Idling/Radiator Hose Hot/Closed Throttle/Park or Neutral/Closed Loop/Accessories Off/Brake Pedal Released | |||
| 3X Crank Sensor | Eng 2 | RPM | Varies |
| 18X Crank Sensor | Eng 2 | RPM | Varies |
| A/C High Side Pressure Sensor | Eng 2 | KPa/PSI/Volts | Varies |
| A/C Off For WOT | Eng 2 | Yes/No | No |
| A/C Pressure Disable | Eng 2 | Yes/No | No |
| A/C Relay Command | Eng 1, 2, Misfire, EGR | On/Off | Off |
| A/C Relay Circuit Status | ODD | OK/Fault/Invalid State | OK |
| A/C Request Signal | Eng 2 | Yes/No | No |
| Air Fuel Ratio | Eng 2, Fuel Trim | Ratio | 14.2:1-14.7:1 |
| APP Average | TAC | Number | 0 |
| APP Indicated Angle | Eng 1, 2, EGR, EVAP, TAC, Fuel Trim, CC | Percent | 0 |
| APP Sensor 1 | TAC | Volts | Varies |
| APP Sensor 2 | TAC | Volts | Varies |
| APP Sensor 1 | TAC | Percent | Varies |
| APP Sensor 2 | TAC | Percent | Varies |
| APP Sensor 1 and 2 | TAC | Agree/Disagree | Agree |
| BARO | Eng 1, EGR, EVAP, Fuel Trim | KPa | 65-110 kPa |
| Boost Solenoid Circuit Status | ODD | OK/Fault/Invalid State | OK |
| Boost Solenoid Command | Engine 2 | Percent | 100% |
| CMP Sensor Signal Present | Eng 2 | Yes/No | Yes |
| Cruise Control Active | Eng 1, CC, TAC | Yes/No | No |
| Cruise Disengage History 1-6 | CC | None | None |
| Cruise Mode Signal | CC | Volts | 0.0 |
| Cruise ON/OFF Switch | CC, TAC | On/Off | Off |
| Cruise Resume/Accel Switch | CC, TAC | On/Off | Off |
| Cruise Set/Coast Switch | CC, TAC | On/Off | Off |
| Current Gear | Eng 1, Eng 2, EGR, Fuel Trim | 1, 2, 3, 4 | 1 |
| Cycles of Misfire Data | Misfire | Counts | 0-99 |
| Cyl. 1-6 Injector Circuit Status | ODD | OK/Stuck Low (open)/Stuck High | OK |
| Decel Fuel Cut-off | EGR, Fuel Trim | Active/Inactive | Inactive |
| Desired EGR Position | Eng 1, EGR, Misfire | Percent | 0 |
| Desired EGR Position | EGR | Volts | 0 |
| Desired Idle Speed | Eng 1, 2, EVAP, TAC | RPM | Varies |
| Driver Module 1 Status | ODD | Enabled/Off-High Volts/Off High Temp/Invalid State | Enabled |
| Driver Module 2 Status | ODD | Enabled/Off-High Volts/Off High Temp/Invalid State | Enabled |
| Driver Module 3 Status | ODD | Enabled/Off-High Volts/Off High Temp/Invalid State | Enabled |
| EC Ignition Relay Circuit | ODD | OK/Fault/Invalid State | OK |
| ECT Sensor | Eng 1, 2, EGR, EVAP, Misfire, Fuel Trim | °C/°F | Varies |
| EGR Flow Test Count | EGR | Counts | 0-12 |
| EGR Learned Minimum Position | EGR | Volts | 0.14-1.0 |
| EGR Position Sensor | Eng 1, EGR, Misfire | Percent | Varies |
| EGR Position Sensor | EGR | Volts | 0 |
| EGR Position Variance | EGR | Percent | 0 |
| EGR Solenoid Circuit Status | ODD | OK/Fault/Invalid State | OK |
| EGR Solenoid Command | EGR | Percent | 0 |
| Engine Load | Eng 1, 2, Misfire, Fuel Trim, EVAP, EGR, CC, TAC | Percent | 0 |
| Engine Oil Level Switch | Eng 2 | OK/Low | OK |
| Engine Oil Life Remaining | Eng 2 | Percent | 0-100% (Varies) |
| Engine Oil Pressure Switch | Eng 2 | Low/OK | OK |
| Engine Run Time | Eng 1, 2, EVAP, Misfire, Fuel Trim, EGR, CC, TAC | Hr: Min: Sec | Varies |
| Engine Speed | Eng 1, 2, EGR, EVAP, Misfire, Fuel Trim, CC, TAC | RPM | Varies |
| EVAP Fault History | EVAP | No Fault/Excess Vacuum/Purge Valve Leak/Small Leak/Weak Vacuum | No Fault |
| EVAP Purge Solenoid Circuit Status | ODD | OK/Fault/Invalid State | OK |
| EVAP Purge Solenoid Command | Eng 1, EVAP, Fuel Trim | Percent | Varies |
| EVAP Vent Solenoid Command | Eng 1, EVAP, Fuel Trim | Venting/Not Venting | Varies |
| EVAP Vent Solenoid Circuit Status | ODD | OK/Fault/Invalid State | OK |
| FC Relay 1 Circuit Status | ODD | OK/Fault/Invalid State | OK |
| FC Relay 1 Command | Eng 2 | On/Off | Off |
| FC Relay 2 and 3 Circuit Status | ODD | OK/Fault/Invalid State | OK |
| FC Relay 2 and 3 Command | Eng 2 | On/Off | Off |
| Fuel Pump Relay Circuit Status | ODD | OK/Fault/Invalid State | OK |
| Fuel Pump Relay Command | Eng 1 | On/Off | On |
| Fuel Tank Level Remaining | EVAP | Percent | 0-104 |
| Fuel Tank Pressure Sensor | Eng 1, EVAP | Mm Hg/in H2O | Varies |
| Fuel Tank Pressure Sensor | EVAP | Volts | Varies |
| Fuel Trim Cell | EVAP, Eng 1, Fuel Trim | 0-4 | 0 |
| Fuel Trim Learn | Eng 1, EVAP, Fuel Trim | Enabled/Disabled | Varies |
| GEN L-Terminal Signal Command | Eng 2 | On/Off | Off |
| HO2S 1 | EVAP, Eng 1, Fuel Trim | Millivolts | 0-1000 and Varying |
| HO2S 2 | Eng 1, Fuel Trim | Millivolts | 0-1000 and Varying |
| HO2S 1 Heater Circuit Status | ODD | OK/Fault | OK |
| HO2S 2 Heater Circuit Status | ODD | OK/Fault | OK |
| HO2S 1 Heater Command | Eng 2 | On/Off | On |
| HO2S 2 Heater Command | Eng 2 | On/Off | On |
| HO2S 1 Heater Current | Eng 2 | Amps | Varies |
| HO2S 2 Heater Current | Eng 2 | Amps | Varies |
| IAT Sensor | Eng 1, 2, EVAP, EGR, Fuel Trim | °C/°F | Varies |
| Ignition 1 Signal | EVAP, Eng 1, 2, EGR, Fuel Trim, CC, TAC | Volts | Varies |
| Ignition Mode | Eng 2 | IC/Bypass | IC |
| IMS | Eng 1, 2, EGR, Fuel Trim, CC | P, R, N, D4, D, 3, D2, D1 | P |
| Initial Brake Apply Signal | CC, TAC | Released/Applied | Released |
| Injector PWM | Eng 2, Fuel Trim, Misfire | Milliseconds | Varies |
| Knock Retard | Eng 1, EGR | Degrees | 0 |
| Long Term FT | Eng 1, 2, EVAP, Fuel Trim | Percent | 10% to +10% |
| Loop Status | Eng 1, 2, Fuel Trim, EVAP, EGR | Open/Closed | Closed |
| MAF Sensor | Eng 1, 2, EGR, Misfire, EVAP, Fuel Trim, TAC | G/s | 3-6 (Varies with altitude) |
| MAF Sensor | Eng 2 | Hz | 1,200-3,000 (depends on altitude) |
| MAP Sensor | Eng 1, 2 | Volts | 0.4-2.0 Volts |
| MAP Sensor | Eng 1, 2, EVAP, Fuel Trim, Misfire, EGR, TAC | KPa | 20-48 kPa (Varies with altitude) |
| MIL Command | Eng 2 | On/Off | Off |
| MIL Circuit Status | ODD | OK/Fault/Invalid State | OK |
| Misfire Current Cyl. 1-6 | Misfire | Counts | 0-4 |
| Misfire History Cyl. 1-6 | Misfire | Counts | 0 |
| Number of DTCs | Eng 1, EVAP, Fuel Trim, TAC | Number | 0 |
| PCM/VCM in VTD Fail/Enable | Eng 1 | Yes/No | No |
| Power Enrichment | Eng 2, Misfire | Active/Inactive | Inactive |
| Reduced Engine Power | Eng 1, TAC, Misfire, CC | Active/Inactive | Inactive |
| Short Term FT | Eng 1, 2, EVAP, Fuel Trim | Percent | 10 to +10 |
| Spark | Eng 1, 2, Misfire, Fuel Trim | Degrees | 22 (varies) |
| Starter Enable Relay Circuit Status | ODD | OK/Fault | OK |
| Starter Relay Command | Eng 2 | On/Off | Off |
| Start Up ECT | EVAP, Fuel Trim | °C/°F | Varies |
| Start Up IAT | EVAP, Fuel Trim | °C/°F | Varies |
| Stop Lamp Signal | CC, TAC | On/Off | Off |
| TAC/PCM Communications Signal | Eng 1, CC, TAC | OK/Fault | OK |
| TCC Brake Pedal Switch | Eng 2 | Applied/Released | Released |
| TCC PWM Solenoid Circuit Status | ODD | OK/Fault/Invalid State | OK |
| TCC PWM Solenoid Command | Eng 2, Misfire, CC | On/Off | Off |
| TCS Delivered Torque Circuit Status | ODD | OK/Fault | OK |
| Torque Request Signal (If Equipped) | Eng 2, TAC | Percent | 100% |
| Torque Delivered Signal (If Equipped) | Eng 2, TAC | Percent | 75% |
| TP Desired Angle | Eng 1, 2, EGR, TAC, Fuel Trim, EVAP, CC | Percent | Varies |
| TP Indicated Angle | Eng 1, 2, EGR, Fuel Trim, EVAP, Misfire, CC, TAC | Percent | % |
| TP Sensor 1 | TAC | Volts | Varies |
| TP Sensor 2 | TAC | Volts | Varies |
| TP Sensor 1 | TAC | Percent | Varies |
| TP Sensor 2 | TAC | Percent | Varies |
| TP Sensor 1 and 2 | TAC | Agree/Disagree | Agree |
| Traction Control Status (If Equipped) | Eng 2, CC, TAC | Active/Inactive | Inactive |
| Vehicle Speed Sensor | Eng 1, 2, EGR, EVAP, Fuel Trim, Misfire, CC, TAC | Mph/km/h | 0 |
| VTD Auto Learn Timer | Eng 1 | Active/Inactive | Inactive |
| VTD Fuel Disable | Eng 1 | Active/Inactive | Inactive |
| VTD Fuel Disable until Ignition Off | Eng 1 | Yes/No | No |
Scan Tool Data List
Scan Tool Output Controls
| Scan Tool Output Control | Additional Menu Selection(s) | Description |
|---|---|---|
| Crankshaft Position Variation Learn | Enables the powertrain control module (PCM) to learn the variations in the crankshaft position (CKP) system. The PCM will learn the variations once the following conditions are met: Engine coolant temperature (ECT) is more than a specific value All the instructions on the scan tool have been completed the accelerator pedal smoothly applied until the fuel cut-off, as specified on the scan tool, is achieved and then immediately released The PCM learns the variation values on the deceleration from the fuel cut-off. | |
| Boost Solenoid (L32) | Engine Output Controls | Activates the boost solenoid at 100 percent duty cycle. |
| Cylinder Power Balance | Fuel System | Enables/Disables a cylinder by turning OFF the fuel injector to the cylinder. The fuel injector is normally enabled. The PCM disables the fuel injector when the following conditions are met: All instructions on the scan tool are completed. Stabilized engine speed Fuel injector selected When DISABLE is selected, the PCM turns the injector OFF for 30 seconds. During this period, the engine operates with a misfire. |
| EGR Solenoid | Engine Output Controls | Activates the exhaust gas recirculation (EGR) solenoid in 10 percent increments from 0 to 100 percent or a maximum of 30 seconds at 100 percent. |
| Engine Speed Control | TAC System | Activates the throttle activation control (TAC) system to change engine RPM. The normal commanded state is None. To enable the RPM control, all instruction on the scan tool must be completed. The system will increase or decrease the RPM within a range of 350-2,000 RPM. The set step value changes the RPM by increments of 25 RPM, 100 RPM and 500 RPM. The system remains in the commanded state until cancelled by the scan tool. |
| EVAP Purge Solenoid | Engine Output Controls/EVAP System | Activates the purge solenoid in 10 percent increments from 0 to 100 percent. The device control will be aborted and inhibited if the fuel tank pressure (FTP) sensor exceeds 19 mm Hg (10 in H2O). |
| EVAP Vent Solenoid | Engine Output Controls/EVAP System | Activates the vent solenoid. The device control will be aborted and inhibited if the FTP sensor exceeds 19 mm Hg (10 in H2O). |
| EVAP Purge/Seal | Engine Output Controls/EVAP System | Simultaneously activates the purge solenoid in 10 percent increments from 0 to 100 percent and the vent solenoid. The device control will be aborted and inhibited if the FTP sensor exceeds 19 mm Hg (10 in H2O). |
| Fuel Injector Balance | Fuel System | Enables the fuel injector in order to verify proper fuel injector flow. The PCM will pulse the selected injector when the following conditions are met: All instruction on the scan tool completed. Fuel injector selected Key ON, engine OFF The selected fuel injector can only be flowed/pulsed once per ignition cycle. |
| Fuel Pump | Engine Output Controls | Activates the fuel pump relay for 2 seconds. Also turns fuel pump ON and OFF while engine is running. |
| Fuel Trim Enable | Fuel System | Disables the PCMs ability to learn new fuel trim parameters. The commanded states are NONE, ENABLED, DISABLED. The normal commanded state is NONE. The system remains in the commanded state until cancelled by the scan tool. |
| Fuel Trim Reset | Fuel System | Activates the reset of fuel trim data in all fuel trim cells. |
| Loop Status | Engine Output Controls | Controls the system loop status. The commanded states include NONE, OPEN, or CLOSED. The normal commanded state is NONE. When commanded OPEN or CLOSED, the system remains in the commanded state until cancelled by the scan tool. |
| MIL | Engine Output Controls/Dash Lamps | Activates the malfunction indicator lamp (MIL). The MIL will remain illuminated until cancelled by the scan tool. |
| Misfire Graphic | Graphs the accumulated misfires occurring in each cylinder. The scan tool allows for a reset of the misfire graph. | |
| O2S Heater Driver | Engine Output Controls | Activates the heated oxygen sensor (HO2S) heater. The commanded states include NONE, ON and OFF. The normal commanded state is NONE. On a cold engine, with the key ON, engine OFF, the HO2S signal will continue to drop below bias when commanded ON. The system remains in the commanded state until cancelled by the tool. |
| EVAP Test | Service Bay Test | Activates the Service Bay Test to verify the integrity of the EVAP system. The scan tool initiates the test when the following conditions are met: All instruction on the scan tool have been completed No DTCs are set |
Powertrain Control Module Scan Tool Output Control