Diagnostic Starting Point - Engine Controls
Begin the system diagnosis with Diagnostic System Check - Engine Controls . The Diagnostic System Check-Engine Controls 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 status
The use of the Diagnostic System Check-Engine Controls will identify the correct procedure for diagnosing the system and where the procedure is located.
Description
The Diagnostic System Check-Engine Controls is an organized approach to identifying a condition that is created by a malfunction in the engine control system. The Diagnostic System Check must be the starting point for any driveability concern. The Diagnostic System Check directs the service technician to the next logical step in order to diagnose the concern. Understanding and correctly using the diagnostic table reduces diagnostic time and prevents the replacement of good parts.
Test Description
The number below refers to the step number on the diagnostic table.
- 12: This step is for areas that have inspection and maintenance testing procedures for emissions testing. Use this step if the testing facility found one or more I/M system statuses that did not set.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Perform the following preliminary inspections: Ensure that the battery is fully charged. Refer to Battery Inspection/Test in Engine Electrical. Ensure that the battery cables are clean and tight. Inspect the easily accessible systems or the visible system components for obvious damage or conditions that could cause the symptom. Refer to Strategy Based Diagnosis in General Information. Ensure that the engine and control module grounds are clean, tight, and in the correct location. Inspect for aftermarket devices that could affect the operation of the system. Refer to Checking Aftermarket Accessories in Wiring Systems. Ensure the resistance between the engine control module (ECM) housing and the battery negative cable is less than 0.5 ohms. Did you find and correct the condition? | System OK | Go to Step 2 |
| 2 | Install a scan tool using the J-45289 Controller Area Network Diagnostic Interface (CANdi) Module. Turn ON the scan tool. Does the scan tool turn ON? | Go to Step 3 | Go to Scan Tool Does Not Power Up in Data Link Communications |
| 3 | Turn ON the ignition, with the engine OFF. Attempt to establish communication with the ECM. Does the scan tool communicate with the ECM? | Go to Step 4 | Go to Data Link References in Data Link Communications |
| 4 | IMPORTANT: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode. Access the Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool. Rotate the ignition switch through all positions while observing the ignition switch power mode parameter. Refer to the Body Control System Description and Operation in Body Control Systems, for a list of the power mode states that correspond to each ignition switch position. Does the ignition switch parameter reading match the ignition switch position for all switch positions? | Go to Step 5 | Go to Power Mode Mismatch in Body Control System |
| 5 | Attempt to start the engine. Does the engine crank? | Go to Step 6 | Go to Symptoms - Engine Electrical in Engine Electrical |
| 6 | Did the engine start and idle? | Go to Step 7 | Go to Engine Cranks but Does Not Run |
| 7 | IMPORTANT: Do NOT clear the DTCs unless instructed by a diagnostic procedure. Select the DTC display function for the engine control module and record the DTCs. If multiple powertrain DTCs are stored, diagnose the DTCs in the following order: Test for component level DTCs. For example, sensor DTCs, solenoid DTCs, and relay DTCs Begin with the lowest number DTC unless the diagnostic table directs you otherwise. Test for system level DTCs. For example, misfire DTCs, EVAP system DTCs and fuel trim DTCs. If there are any powertrain DTCs, Select Capture Info in order to store the Powertrain DTC information with a scan tool. Does the scan tool display any DTCs? | Go to Step 8 | Go to Step 11 |
| 8 | Does the scan tool display DTCs which begin with a "U"? | Go to Data Link References in Data Link Communications | Go to Step 9 |
| 9 | Does the scan tool display DTCs P0601, P0602, P0604, or P0606? | Go to DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610 | Go to Step 10 |
| 10 | Does the scan tool display DTCs P0560, P0562, P0563, P0625, P0626, or P1668? | Go to Diagnostic Trouble Code (DTC) List in Engine Electrical | Go to Diagnostic Trouble Code (DTC) List |
| 11 | Are there any transmission control module (TCM) DTCs or any automatic transmission symptoms? | Go to Diagnostic System Check - Automatic Transmission in Automatic Transmission 5L40-E | Go to Step 12 |
| 12 | Is the customer's concern with Inspection and Maintenance (I/M) testing? | Go to Inspection/Maintenance (I/M) System Check | Go to Step 13 |
| 13 | Are there any engine controls or driveability symptoms observed? | Go to Symptoms - Engine Controls | System OK |
| IMPORTANT |
|---|
| The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode. |
| IMPORTANT |
|---|
| Do NOT clear the DTCs unless instructed by a diagnostic procedure. |
A Diagnostic System Check for Engine Controls
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 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 conditions are determined
- The Diagnostic System Check-Engine Controls is completed.
- There are no diagnostic trouble codes (DTCs).
- The on-board diagnostics are functioning correctly.
Scan tool values from an engine that is operating correctly may be used for comparison with the engine you are diagnosing. The Engine Scan Tool Data List represents the values that would be seen on a normal operating engine.
| IMPORTANT | Do not use a scan tool that displays faulty data. The scan tool concern should be reported to the manufacturer. Use of a faulty scan tool may 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 is located on the scan tool. Review 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 | Parameter Range/Units | Typical Data Values |
|---|---|---|---|
| Engine Idling/Radiator Hose Hot/Park or Neutral/Closed Loop/Accessories Off | |||
| A/C Disengage 1-8 History | CH | Reason for A/C Disengagement | Varies |
| A/C High Side Pressure Sensor | CH | 0-5 Volts | Varies |
| A/C OFF for WOT | CH | Yes/No | No |
| A/C Pressure Disable | CH | Yes/No | No |
| A/C Relay Circuit Status | ODM | OK/Fault/Indeterminate | OK |
| A/C Relay Command | Eng 1, 2, MF, FF, FR, CH | On/Off | Off |
| A/C Request Signal | CH | Yes/No | No |
| APP Indicated Angle | Eng 1, 2, CMP, CT, EVAP, HO2S, FF, FR, FT, TAC | 0-100% | 0% |
| APP Sensor 1 | FF, FR, TAC | 0.9-4.5 Volts | 1 Volt |
| APP Sensor 2 | FF, FR, TAC | 0.45-2.25 Volts | 0.5 Volt |
| APP Sensor 1 and 2 | FF, FR, TAC | Agree/Disagree | Agree |
| BARO | Eng 1, 2, CMP, EVAP, FF, FR, HO2S, FT, MF, TAC | 65-104 kPa (8-16 psi) | Varies with altitude |
| Brake Pedal Signal Status | CT, TAC | Valid/Invalid | Valid |
| Calculated ECT - Closed Loop Fuel Control | Eng 2 | 39°C to +40°C (-38°F to +104°F) | 40°C (104°F) |
| Calculated ECT - Thermostat Diagnosis | Eng 2 | 39°C to +140°C (-38°F to +284°F) | 89°C (192°F) |
| Catalytic Converter Protection Active | FF, FR, FT, MF | Yes/No | No |
| Crank Request Signal | ET | Yes/No | No |
| Cruise Control Active | CT, IPC, FF, FR | Yes/No | No |
| Cruise Disengage 1-8 History | CT | Reason | Varies |
| Cruise Inhibit Reason | CT | Reason | Varies |
| Cruise On/Off Switch | CT | On/Off | Off |
| Cruise Resume/Accel. Switch | CT | On/Off | Off |
| Cruise Set/Coast Switch | CT | On/Off | Off |
| Current Gear | Eng 1, 2, FF, FR, FT, MF, CT, ET, IPC | P/N/Reverse/1st-5th | P/N |
| Current Gear Signal | ET, FF, FR | Valid/Invalid | Valid |
| Cycles of Misfire Data | FF, FR, MF | 0-200 counts | Varies |
| Cylinder 1-6 Injector Circuit Status | ODM | OK/Fault/Indeterminate | OK |
| Cylinder 1-6 Knock Retard | Eng 1 | Degree | 0 Degrees |
| Decel. Fuel Cutoff | Eng 2, FF, FR, FT, HO2S | Active/Inactive | Inactive |
| Desired Exh. CMP Bank 1 or 2 | CMP, FF, FR | Degree | Varies |
| Desired HO2S Bank 1 or 2 Sensor 1 | HO2S, FF, FR | Lambda | Varies |
| Desired Idle Speed | Eng 1, 2, EVAP, CMP, FF, FR, TAC | 0-7,000 RPM | 650 RPM |
| Desired Int. CMP Bank 1 or 2 | CMP, FF, FR | Degrees | Varies |
| DTC Set This Ignition | Eng 1, CMP, EVAP, FT, HO2S, TAC | Yes/No | No |
| EC Ignition Relay Command | Eng 1, TAC, ET, FF, FR | On/Off | On |
| EC Ignition Relay Feedback Signal | Eng 1, TAC, ET, FF, FR | 0-25.5 Volts | 12.0-14.5 Volts |
| ECM Reset | Eng 1, EVAP, FT, FF, FR | Yes/No | No |
| ECT Sensor | Eng 1, 2, CMP, EVAP, HO2S, FF, FR, FT, MF, TAC, CH, IPC | 39°C to +140°C (-38°F to +284°F) | Varies |
| Engine Load | Eng 1, 2, CMP, EVAP, HO2S, FF, FR, FT, MF, TAC, CH | 0-99% | 0-5% - Idle 3-7% - 2500 RPM |
| Engine OFF EVAP Test Conditions Met | EVAP | Yes/No | Varies |
| Engine Off Time | EVAP, FF, FR | 0:00:00 Seconds | Varies |
| Engine Oil Level Switch | CMP, IPC | OK/Low | OK |
| Engine Oil Pressure Sensor | IPC, FF, FR | OK, Low | OK |
| Engine Oil Pressure Sensor | MF, CMP, IPC, FF, FR | KPa/psi | Varies |
| Engine Run Time | Eng 1, 2, EVAP, FT, HO2S, MF, TAC, CMP, ODM, CH, FF, FR | 0:00:00 | Varies |
| Engine Speed | ALL | RPM | 575-700 RPM |
| EVAP Purge Solenoid Circuit Status | ODM | OK/Fault/Indeterminate | OK |
| IMPORTANT: This parameter may not change states when using the EVAP Purge Solenoid output control. EVAP Purge Solenoid Command | Eng 1, EVAP, FF, FR, FT | 0-100% | Varies |
| EVAP Vent Solenoid Circuit Status | ODM | OK/Fault/Indeterminate | OK |
| IMPORTANT: This parameter may not change states when using the EVAP Vent Solenoid output control. EVAP Vent Solenoid Command | Eng 1, EVAP, FF, FR, FT | Venting/Not Venting | Varies |
| Exh. CMP Angle Bank 1 or 2 | CMP, FF, FR | Degrees | Varies |
| Exh. CMP Bank 1 or 2 Command | CMP, FF, FR | 0-99% | Varies |
| Exh. CMP Solenoid Bn. 1 or 2 Circuit Status | ODM | OK/Fault/Indeterminate | OK |
| Extended Travel Brake Pedal Switch | Eng 1, TAC, CT | Applied/Released | Released |
| Fail Counter | FF, FR | Counts | Varies |
| FC Relay 1 Circuit Status | ODM | OK/Fault/Indeterminate | OK |
| FC Relay 1 Command | Eng 2, CH, FF, FR | ON/OFF | Varies |
| IMPORTANT: This parameter may not change from OFF to ON or ON to OFF when using the Fan output control. FC Relays 2 and 3 Command | Eng 2, CH, FF, FR | ON/OFF | Varies |
| FC Relays 2 and 3 Circuit Status | ODM | OK/Fault/Indeterminate | OK |
| Fuel Level Sensor Left Tank (Secondary) | EVAP, IPC, FF, FR | 0-5 Volts | Varies |
| Fuel Level Sensor Right Tank (Primary) | EVAP, IPC, FF, FR | 0-5 Volts | Varies |
| Fuel Pump Relay Circuit Status | ODM | OK/Fault/Indeterminate | OK |
| IMPORTANT: This parameter may not change from OFF to ON or ON to OFF when using the Fuel Pump output control. Fuel Pump Relay Command | Eng 1, 2, FF, FR | On/Off | On |
| Fuel Tank Level Remaining | Eng 1, EVAP, IPC, MF | Liter/Gallon | Varies |
| Fuel Tank Pressure Sensor | EVAP, FF, FR | In H2O/mm Hg | Varies |
| Fuel Tank Pressure Sensor | EVAP, FF, FR | 0-5 Volts | Varies |
| Fuel Tank Rated Capacity | EVAP | Liter/Gallon | 17.8 Gallons (67.3 Liters) |
| Fuel Trim Learn | Eng 1, EVAP, FT, HO2S, FF, FR | Enabled/Disabled | Enabled |
| GEN L-Terminal Signal Command | ET | 0-100% | Varies |
| Generator F-Terminal Signal | ET | 0-100% | Varies |
| HO2S Bank 1 or 2 Sensor 1 | Eng 1, EVAP, FT, HO2S, FF, FR | Lambda | 1.0 Lambda |
| HO2S Bank 1 or 2 Sensor 2 | Eng 1, FT, HO2S, FF, FR | 0-1,006 mV | Varies 400-700 mV |
| HO2S Htr. Bn. 1 or 2 Sensor 1 or 2 Circuit Status | ODM | OK/Fault/Indeterminate | OK |
| HO2S Htr. Bn. 1 or 2 Sensor 1 Command | HO2S, FF, FR | 0-99% | Varies |
| HO2S Sensing Element Bn. 1 or 2 Sensor 1 | HO2S | Ohms | 70-90 Ohms Depends on Temperature |
| IAT Sensor | Eng 1, 2, EVAP, FT, HO2S, TAC, CMP, CH, FF, FR | 39° to +140°C (-38° to +284°F) | Varies |
| Ignition 0 Signal | Eng 1, 2 EVAP, TAC, ET, IPC, FF, FR | On/Off | On |
| Ignition 1 Signal | Eng 1, 2 EVAP, FT, MF, TAC, CMP, ET, IPC, FF, FR | On/Off | On |
| IMRC Solenoid Circuit Status | ODM | OK/Fault/Indeterminate | OK |
| IMPORTANT: This parameter may not change from OFF to ON or ON to OFF when using the IMRC Solenoid output control. IMRC Solenoid Command | Eng 1 | On/Off | Off |
| Initial Brake Apply Signal | TAC, CT | Applied/Released | Released |
| Injector 1-6 Command | Eng 2, FT, MF | Ms | Varies |
| Injector PWM Bank 1 or 2 Average | FT, MF, FF, FR | 0-9 ms | 4.6-5.4 ms |
| Int. CMP Angle Bank 1 or 2 | CMP, FF, FR | Degrees | Varies |
| Int. CMP Bank 1 or 2 Command | CMP, FF, FR | 0-99% | Varies |
| Int. CMP Solenoid Bn. 1 or 2 Circuit Status | ODM | OK/Fault/Indeterminate | OK |
| Knock Retard | Eng 1, CH, FF, FR | Degrees | Varies |
| KS 1 or 2 Signal | Eng 1 | Volts | Varies |
| Loop Status Bn 1 or 2 Sen. 1 | Eng 1, 2, EVAP, FT, HO2S, FF, FR | Open Loop/Closed Loop | Closed Loop |
| Loop Status Bn 1 or 2 Sen. 2 | Eng 1, 2, EVAP, FT, HO2S, FF, FR | Open Loop/Closed Loop | Open Loop |
| LT FT Bn. 1 or Bn. 2 Cruise/Accel. | Eng 1, 2, EVAP, FT, HO2S, FF, FR | 100% to +100% | 0% |
| LT FT Bn. 1 or Bn. 2 Idle/Decel. | Eng 1, 2, EVAP, FT, HO2S, FF, FR | 100% to +100% | 0% |
| MAF Sensor | Eng 1, 2, FT, HO2S, MF, TAC, CMP, FF, FR | 0-655 g/s | 3.4-6.3 g/s |
| MAF Sensor | Eng 2, EVAP, FT, HO2S, MF, TAC, CMP, FF, FR | 0-5 Volts | 0.9-1.7 Volts |
| MIL Circuit Status | ODM | OK/Fault/Indeterminate | OK |
| IMPORTANT: This parameter may not change from OFF to ON or ON to OFF when using the MIL output control. MIL Command | Eng 1, IPC | On/Off | Off |
| Mileage Since DTC Cleared | Eng 2, FF, FR | Km - miles | Varies |
| Mileage Since First Failure | FF, FR | Km - miles | Varies |
| Mileage Since Last Failure | FF, FR | Km - miles | Varies |
| Mileage Since MIL Requested | FF, FR | Km - miles | Varies |
| Misfire Current Cyl. 1-6 | MF | 0-255 Counts | 0 |
| Moderate Brake Apply Signal | TAC, CT | Applied/Released | Released |
| Not Run Counter | FF, FR | Counts | Varies |
| Pass Counter | FF, FR | Counts | Varies |
| PNP Switch | Eng 2, ET, FF, FR | Park/Neutral/In Gear | P/N |
| Power Enrichment | Eng 2, FT, HO2S, MF, FF, FR | Active/Inactive | Inactive |
| Reduced Engine Power | Eng 1, 2, TAC, IPC, FF, FR | Active/Inactive | Inactive |
| Short Term FT Bank 1 or Bank 2 | Eng 1, 2, EVAP, FT, HO2S, FF, FR | 25% to +25% | 3% to +3% |
| Spark | Eng 1, 2, FT, HO2S, MF, CH, CT, FF, FR | 20 to +40 Degrees | 2-10 Degrees |
| Starter Relay Circuit Status | ODM | OK/Fault/Indeterminate | OK |
| IMPORTANT: This parameter may not change from OFF to ON or ON to OFF when using the Starter Relay output control. Starter Relay Command | ET | On/Off | Off |
| Start Up ECT | Eng 2, EVAP, FT, HO2S, CH, FF, FR | 39° to +140°C (-38° to +284°F) | Varies |
| Start Up IAT | Eng 2, EVAP, FT, HO2S, CH, FF, FR | 39° to +140°C (-38° to +284°F) | Varies |
| Stoplamp Pedal Switch | Eng 1, CT, TAC, FF, FR | Applied/Released | Released |
| System Power Mode | Eng 2, EVAP, TAC, ET, FF, FR | Off, Accessory, RAP, Run, or Crank Request | Run |
| TAC System Learned Counts | TAC | 0-11 Counts | 0 |
| Torque Delivered Signal | FT, TAC, CT, FF, FR | 0-100% | Varies |
| Torque Request Signal | FT, TAC, CT, FF, FR | 0-100% | 90-98% |
| Total Fuel Trim Avg. Bank 1 or Bank 2 | EVAP, FT, HO2S, FF, FR | 100 to +100% | Varies |
| Total Misfire Count | MF, FF, FR | Counts | 0 |
| TP Desired Angle | Eng 1, 2, EVAP, TAC, CT, FF, FR | 0-100% | Varies |
| TP Indicated Angle | Eng 1, 2, EVAP, FT, HO2S, MF, TAC, CMP, CT, FF, FR | 0-100% | Varies |
| TP Sensor 1 | TAC, FF, FR | 0-5 Volts | 0.5-0.8 Volts |
| TP Sensor 1 Learned Minimum | TAC, FF, FR | 0-5 Volts | 0-0.6 Volts |
| TP Sensor 2 | TAC, FF, FR | 0-5 Volts | 4.7-4.1 Volts |
| TP Sensor 2 Learned Minimum | TAC, FF, FR | 0-5 Volts | 5-3.7 Volts |
| TP Sensors 1 and 2 | TAC, FF, FR | Agree/Disagree | Agree |
| Traction Control Status | TAC, CT, FF, FR | Active/Inactive | Inactive |
| Transmission Gear Selector Signal | Eng 2 | Valid/Invalid | Valid |
| TWC Temperature Calculated Bank 1 or Bank 2 | FT, MF, FF, FR | 316-1,095°C (600-2,000°F) | 316-485°C (600-900°F) |
| Vehicle Security Status | Eng 2, ET, IPC | Password Learning, VTD Fail-Enable, Auto Learn Timer, Fuel Disable Until Ign Off, Fuel Disable Timeout, and Fuel Continue | Fuel Continued |
| Vehicle Speed Sensor | Eng 1, 2, EVAP, FT, HO2S, MF, TAC, CMP, CH, CT, IPC, FF, FR | Km/h mph | Varies |
| Volumetric Efficiency | Eng 1, 2, EVAP, FT, HO2S, MF, TAC, CMP, CH, FF, FR | 0-100% | 5-25% - Idle and at 2500 RPM |
| IMPORTANT |
|---|
| This parameter may not change states when using the EVAP Purge Solenoid output control. |
| IMPORTANT |
|---|
| This parameter may not change states when using the EVAP Vent Solenoid output control. |
| IMPORTANT |
|---|
| This parameter may not change from OFF to ON or ON to OFF when using the Fan output control. |
| IMPORTANT |
|---|
| This parameter may not change from OFF to ON or ON to OFF when using the Fuel Pump output control. |
| IMPORTANT |
|---|
| This parameter may not change from OFF to ON or ON to OFF when using the IMRC Solenoid output control. |
| IMPORTANT |
|---|
| This parameter may not change from OFF to ON or ON to OFF when using the MIL output control. |
| IMPORTANT |
|---|
| This parameter may not change from OFF to ON or ON to OFF when using the Starter Relay output control. |
Scan Tool Data List
Scan Tool Data Definitions
The Scan Tool Data Definitions list contains a brief description of all of the 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. In some cases the parameter may appear more than once, or in more than one data list in order to group certain related parameters together.
Scan Tool Output Controls
| Scan Tool Output Control | Additional Menu Selection(s) | Description |
|---|---|---|
| Camshaft Actuator Solenoid | Special Functions/Engine Output Controls/CMP Actuator System | This function controls the selected camshaft actuator solenoid. The normal commanded state is NONE. The system will increase or decrease the angle of the selected camshaft in 5 degree increments up to 50 crankshaft degrees. The scan tool initiates the test when the following conditions are met: The vehicle speed is 0 km/h (0 mph). The transmission is in park or neutral. The engine speed is between 1000-1400 RPM. The system remains in the commanded state until cancelled by the scan tool. |
| Cylinder Power Balance | Special Functions/Fuel System | This function disables the selected fuel injector. The normal commanded state is None. The scan tool initiates the test when the following conditions are met: The engine is operating and the engine idle is stable. The vehicle speed is 0 km/h (0 mph). There are no DTCs set for the vehicle speed sensor. If the fuel injector was disabled for 30 seconds, fuel injector control is not allowed again on the same fuel injector for 60 seconds. |
| Engine Speed Control | Special Functions/TAC System | IMPORTANT: DTCs may set when using this output control. This function controls the idle speed override in 20 RPM, 100 RPM, and 500 RPM increments, from the base idle speed to 1400 RPM. The scan tool initiates the test when the following conditions are met: The transmission is in park or neutral. The engine speed is less than 1000 RPM The engine speed will remain in the commanded state until cancelled by the scan tool. |
| EVAP Purge Solenoid | Special Functions/EVAP System | IMPORTANT: This function may be disabled if there is an EVAP DTC set. The EVAP Purge Solenoid Command parameter may not change states when using this output control. This function controls the EVAP purge solenoid valve. The normal commanded state is NONE. The system will Increase or Decrease the amount of purge by changing the duty cycle of the purge valve in 10 percent increments within a range of 0-100 percent. The system remains in the commanded state until cancelled by the scan tool or the fuel tank pressure (FTP) sensor exceeds -24 mm Hg (-12 in H20). |
| EVAP Purge/Seal | Special Functions/EVAP System | IMPORTANT: This function may be disabled if there is an EVAP DTC set. The EVAP Purge and Vent Solenoid Command parameters may not change states when using this output control. This function activates both the EVAP purge solenoid valve and EVAP vent solenoid to seal the EVAP system. When activated, the purge valve is commanded to 0 percent and the vent valve is commanded ON, Not-venting. The normal commanded state for both solenoids is None. Both of the solenoids remain in the commanded state until cancelled by the scan tool or the fuel tank pressure (FTP) sensor exceeds -24 mm Hg (-12 in H20). |
| EVAP Vent Solenoid | Special Functions/EVAP System | IMPORTANT: This function may be disabled if there is an EVAP DTC set. The EVAP Vent Solenoid Command parameter may not change states when using this output control. This function controls the EVAP vent solenoid. The normal commanded state is NONE. When commanded ON, the vent valve switches to Not-venting. The system remains in the commanded state unless one of the following conditions occurs: Cancelled by the scan tool The EVAP canister Purge solenoid is more than 0 percent, and the fuel tank pressure (FTP) sensor exceeds -24 mm Hg (-12 in H20). |
| Fuel Pump | Special Functions/Engine Output Controls | IMPORTANT: The Fuel Pump Relay Command parameter may not change states when using this output control. DTCs may set when using this output control. This function controls the fuel pump relay. The normal commanded state is NONE. The scan tool initiates the test when the following conditions are met: There are no vehicle speed sensor DTCs set. The vehicle speed is 0 km/h (0 mph). When commanded ON/OFF, the ECM turns the fuel pump relay ON/OFF. If the engine is running and the fuel pump relay is commanded OFF, the engine will stall. The system remains in the commanded state for about 2 seconds or until cancelled by the scan tool or the ECM detects a vehicle speed. |
| Fuel Trim Reset | Special Functions/Fuel System | This function resets the fuel trim data and the learned values for the rear heated oxygen sensors. |
| Heated Oxygen Sensor (HO2S) | Special Functions/Engine Output Controls | This function controls the selected HO2S heater control circuit. The normal commanded state is NONE. The system will decrease the duty cycle of the selected HO2S in 10 percent increments down to 0 percent. The system remains in the commanded state until cancelled by the scan tool. |
| IMRC Solenoid | Special Functions/Engine Output Controls | IMPORTANT: The IMRC Solenoid Command parameter may not change states when using this output control. This function controls the IMRC solenoid. The normal commanded state is NONE. When commanded ON/OFF, the ECM turns the IMRC solenoid ON/OFF. The scan tool initiates the test when the following conditions are met: There are no vehicle speed sensor DTCs set. The vehicle speed is 0 km/h (0 mph). The system remains in the commanded state until cancelled by the scan tool. |
| Malfunction Indicator Lamp | Special Functions/Engine Output Controls | IMPORTANT: The MIL Command parameter may not change states when using this output control. This function controls the malfunction indicator lamp (MIL). The normal commanded state is NONE. When commanded ON/OFF, the ECM turns the malfunction indicator lamp (MIL) ON/OFF. The system remains in the commanded state until cancelled by the scan tool. |
| Throttle Position | Special Functions/TAC System | This function controls the throttle valve in 25 percent increments. The scan tool initiates the test when the following conditions are met: There are no vehicle speed sensor DTCs set. The vehicle speed is 0 km/h (0 mph). The ignition is ON, with the engine OFF. The ECM is not commanding a throttle learn. The system remains in the commanded state until cancelled by the scan tool. |
| IMPORTANT |
|---|
| DTCs may set when using this output control. |
| IMPORTANT |
|---|
| This function may be disabled if there is an EVAP DTC set. The EVAP Purge Solenoid Command parameter may not change states when using this output control. |
| IMPORTANT |
|---|
| This function may be disabled if there is an EVAP DTC set. The EVAP Purge and Vent Solenoid Command parameters may not change states when using this output control. |
| IMPORTANT |
|---|
| This function may be disabled if there is an EVAP DTC set. The EVAP Vent Solenoid Command parameter may not change states when using this output control. |
| IMPORTANT |
|---|
| The Fuel Pump Relay Command parameter may not change states when using this output control. DTCs may set when using this output control. |
| IMPORTANT |
|---|
| The IMRC Solenoid Command parameter may not change states when using this output control. |
| IMPORTANT |
|---|
| The MIL Command parameter may not change states when using this output control. |
Scan Tool Output Controls
Diagnostic Trouble Code (DTC) List
Diagnostic Trouble Code (DTC) List
See also:
• Battery Inspection/Test
• Strategy Based Diagnosis
• Checking Aftermarket Accessories
• Scan Tool Does Not Power Up
• Data Link References
• Body Control System Description and Operation
• Symptoms - Engine Electrical
• Engine Cranks but Does Not Run
• DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610
• Diagnostic Trouble Code (DTC) List
• Diagnostic System Check - Automatic Transmission
• DTC P0008
• DTC P0132 or P0152
• DTC P0461 (3.6L (LY7))
• DTC P0480, P0481, P0691, P0692, P0693, or P0694
• DTC P0530, P0532, or P0533
• DTC P0564
• DTC P0850
• DTC C0241 or P0856
• DTC P1551
• DTC P1629
• DTC P2188 or P2190
• Diagnostic Trouble Code (DTC) List
• Diagnostic System Check - Engine Controls
• Diagnostic Trouble Code (DTC) List