Diagnostic Starting Point - Engine Controls
Begin the system diagnosis with the Diagnostic System Check - Engine Controls . The Diagnostic System Check 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 their status
The use of the Diagnostic System Check 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 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 properly.
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 the values that would be seen on a normal running 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 can result in misdiagnosis and in 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 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 High Side Pressure | Input | 0-3,450 kPa / 0-500 psi | Varies |
| A/C High Side Pressure Sensor | Input, Output | 0-5 Volts | Varies |
| A/C Relay Command | Input, Output, Idle | On/Off | Off |
| A/C Request | Input, Idle | Yes/No | No |
| APP at Idle | Idle | Yes/No | Yes |
| APP Sensor 1 | Input, FE, Idle | 0.9-4.5 Volts | 1 Volt |
| APP Sensor 2 | Input, FE, Idle | 0.45-2.25 Volts | 0.5 Volt |
| Battery Voltage | All | 0-25.5 Volts | 12.8-14.2 Volts |
| Brake Switch | Input, Idle | Applied/Released | Released |
| CMP Active Counter | Input, Ign | 0-256 Counts | Varies |
| Cruise Clutch Switch (If Equipped) | Input, Idle | Applied/Released | Released |
| Cruise Switch | Input, Idle | On/Off | Off |
| Cruise Brake Switch | Input, Idle | Applied/Released | Released |
| Cruise Resume/Accel. | Input, idle | On/Off | Off |
| Cruise Set/Coast | Input, idle | On/Off | Off |
| Desired Idle Speed | Idle | 0-7,000 RPM | 650 RPM |
| ECT | ALL | 39 to +140°C/-38 to +284°F | 85-105 °C/185-220°F |
| Engine Load | ALL | 0-99% | 2% |
| Engine Oil Life Left | Input | 0-100% | Varies |
| EGR Duty Cycle | Input, Output, FE, Ign, MF, Aux, Idle | 0-100% | 0% |
| EGR Sensor | Input, Aux | 0-5 Volts | .82 Volts |
| Engine Run Time | ALL | 0:00:00 | Varies |
| Engine Speed | ALL | RPM | 650 RPM |
| EVAP Purge Solenoid DC | Output, FE, Aux | 0-100% | Varies |
| EVAP Vent Solenoid | Output | On/Off | Off |
| Fan Speed | Output | Off/Low/High | Varies |
| Fan Control 1 | Output | On/Off | Varies |
| Fan Control 2 | Output | On/Off | Varies |
| Fuel Level | Input, Ign | Gal/L | Varies |
| Fuel Level | Input, FE, Ign | 0-5 Volts | Varies |
| Fuel Pump Relay Command | Output | On/Off | On |
| Fuel Shut-off Main | Eng | Yes/No | No |
| Fuel Shut-off Sec | Eng | Yes/No | No |
| Fuel Tank Pressure | Input, Aux | In H2O/mm Hg | Varies |
| Fuel Tank Press | Input, Aux | 0-5 Volts | Varies |
| GEN L-Terminal | Input | High/Low | High |
| HO2S Bank 1 or Bank 2 Sensor 1 | Input, FE, Aux | 0-1 Volt | Varies between 0-1 Volt |
| HO2S Bank 1 or Bank 2 Sensor 2 | Input, FE, Aux | 0-1000 mV | Varies 400-800 mV |
| HO2S Bank 1 or Bank 2 Sen. 1 ohms | FE | 0-infinity | 0 |
| HO2S Bank 1 or Bank 2 Sen. 2 ohms | FE | 0-infinity | 0 |
| HO2S Bn 1 or Bn 2 Sen. 1 Heater | FE | On/Off | Varies |
| HO2S Bn 1 or Bn 2 Sen. 1 Heater | FE | On/Off | Varies |
| IAT | ALL | 39 to +140°C/-38 to +284°F | Varies |
| Ignition On | Input | Yes/No | Yes |
| Injector Pulse Width | FE | 0-100 ms | 3.0-5.4 ms |
| Intake Plenum Switchover Valve | Output | On/Off | Off |
| Knock Sensor 1 | Ign | Active/Inactive | Inactive |
| Knock Sensor 2 | Ign | Active/Inactive | Inactive |
| Knock Sensor 1 | Input, Ign | 0.25-2.67 Volts | 1.10 Volts |
| Knock Sensor 2 | Input, Ign | 0.25-2.67 Volts | 1.10 Volts |
| Knock Retard Cyl. 1-6 | Ign | 0-191 Degrees | 0 Degrees |
| Low Oil Pressure | Input | Yes/No | No |
| LT FT Bn. 1 or Bn. 2 Cruise/Accel. | FE, Aux | 100 to 100% | 0% |
| LT FT Bn. 1 or Bn. 2 Idle/Decel. | FE, Aux | 100 to +100% | 0% |
| Loop Status Bank 1 or Bank 2 | FE | Open/Closed | Closed |
| MAF | ALL | 0-655 g/s | 3.4-6.3 g/s |
| MAF Sensor | Input | 0-5 Volts | 1.2-1.5 Volts |
| Main Relay Command | Output | On/Off | On |
| MAP | ALL | KPa/Volts | 45 |
| Misfire Current Cyl. 1-6 | MF | 0-255 Counts | 0 |
| Misfire History Cyl. 1-6 | MF | 0-255 Counts | 0 |
| Park/Neutral Switch (If Equipped) | Idle | P-N/R-D-L | P-N |
| Short Term FT Bank 1 or Bank 2 | FE, Aux | 100 to +100% | 3% to +3% |
| Spark | Ign | 133 to +78 Degrees | 2-5 Degrees |
| TAC Learn Counter | Eng | 0-255 Counts | Varies |
| TAC Limit Authority | Eng | Yes/No | No |
| TAC Limit Power | Eng | Yes/No | No |
| Torque Delivered | Input | 0-100% | 0% |
| Torque Requested | Input | 0-100% | 100% |
| TP Angle | ALL | 0-99% | 0 percent |
| TP Sensor 1 | Input, FE, Idle | 0-5 Volts | 0.5-0.8 Volts |
| TP Sensor 2 | Input, FE, Idle | 0-5 Volts | 4.1-4.5 Volts |
| Vehicle Speed | ALL | Km/mi | Varies |
Scan Tool Data List
Scan Tool Data Definitions
The Engine Scan Tool Data Definitions contains a brief description of all engine related parameters available on the scan tool. The list is in alphabetical order.
Scan Tool Output Controls
| Scan Tool Output Control | Additional Menu Selection(s) | Description |
|---|---|---|
| Engine Speed Control | Special Functions/TAC System | This function activates the idle speed override in 20 RPM, 100 RPM, and 500 RPM increments, from 600 RPM to 1700 RPM. The engine speed will remain in the commanded state until cancelled by the tool. |
| EGR Solenoid | Special Functions/EGR System | This function activates the exhaust gas recirculation (EGR) solenoid in 10 percent increments from 0 to 100 percent or a maximum of 30 seconds at 100% |
| EVAP Purge Solenoid (PWM) | Special Functions/EVAP System | This function activates 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 percent-100 percent. The system remains in the commanded state until cancelled by the tool or the fuel tank pressure (FTP) exceeds -24 mm Hg (-12 in H20). |
| EVAP Purge/Seal | Special Functions/EVAP System | This function activates two functions. One function increases or decreases the amount of purge by changing the duty cycle of the purge valve and commanding the vent ON, non-venting. The normal commanded state of both valves is NONE. The system will INCREASE or DECREASE the amount of EVAP purge valve opening by 10 percent increments within a range of 0 percent-100 percent. The second function seals the system after using the purge function to obtain a specific amount of fuel tank pressure (FTP). When activated, the purge valve is commanded to 0 percent and the vent valve is commanded ON, non-venting. Both functions remain in the commanded state until cancelled by the tool or the FTP exceeds -24 mm Hg (-12 in H20). |
| EVAP System Seal | Special Functions/EVAP System | When activated, the purge valve is commanded to 0 percent and the vent valve is commanded ON, non-venting. This functions remain in the commanded state until cancelled by the tool or the FTP exceeds -24 mm Hg (-12 in H20). |
| EVAP Service Bay Test | Special Functions/EVAP System | This function 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 the instructions on the scan tool have been completed The engine coolant temperature is less then a specified value No DTCs are set |
| EVAP Vent Solenoid | Special Functions/EVAP System | This function activates the EVAP vent solenoid. The normal commanded state is NONE. When commanded ON, the vent valve switches to non-venting. The system remains in the commanded state unless one of the following conditions occurs: Cancelled by the tool Purge is greater than 0 percent, and the fuel tank pressure (FTP) exceeds -24 mm Hg (-12 in H20) |
| Fuel Pump | Special Functions/Engine Output Controls | This function activates the fuel pump relay. The normal commanded state is NONE. 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 until cancelled by the scan tool. |
| Fuel Economy Test | Special Functions/Fuel System | When the Test is ENABLED the ECM calculates fuel economy based on throttle position, injector pulse width, vehicle speed and engine load. |
| Ignition System | Special Functions/Engine Output Controls | IMPORTANT: The spark tester must be connected to the ignition coil and a good ground before using this function. This function activates the ignition control (IC) circuit for the selected ignition coil for 30 seconds. The scan tool initiates the test when the following conditions are met: The ignition is on with the engine off The vehicle speed is 0 km/h mph Control is not allowed again on the same coil until that ignition coil is allowed to cool for 60 seconds. |
| Intake Plenum Switchover Valve | Special Functions/Engine Output Controls | This function activates the solenoid that supplies vacuum to the IMRC valve located in the intake manifold. The commanded states include NONE, ON and OFF. When commanded ON or OFF, the system remains in the commanded state until cancelled by the scan tool. |
| Throttle Valve Position | Special Functions/TAC System | This function opens the throttle plate in 25 percent increments. The Scan tool initiates the test when the following conditions are met: The ignition is on with the engine off The vehicle speed is 0 km/h mph The system remains in the commanded state until cancelled by the scan tool. |
| IMPORTANT |
|---|
| The spark tester must be connected to the ignition coil and a good ground before using this function. |
Scan Tool Output Controls
Diagnostic Trouble Code (DTC) List
| DTC | Diagnostic Procedure | Module(s) |
|---|---|---|
| P0068 | DTC P0068 | ECM |
| P0106 | DTC P0106 | ECM |
| P0107 | DTC P0107 | ECM |
| P0108 | DTC P0108 | ECM |
| P0112 | DTC P0112 | ECM |
| P0113 | DTC P0113 | ECM |
| P0117 | DTC P0117 | ECM |
| P0118 | DTC P0118 | ECM |
| P0120 | DTC P0120 | ECM |
| P0122 | DTC P0122 | ECM |
| P0123 | DTC P0123 | ECM |
| P0125 | DTC P0125 | ECM |
| P0128 | DTC P0128 | ECM |
| P0130 | DTC P0130 | ECM |
| P0131 | DTC P0131 | ECM |
| P0132 | DTC P0132 | ECM |
| P0133 | DTC P0133 | ECM |
| P0134 | DTC P0134 | ECM |
| P0135 | DTC P0135 or P0141 | ECM |
| P0136 | DTC P0136 | ECM |
| P0137 | DTC P0137 | ECM |
| P0138 | DTC P0138 | ECM |
| P0140 | DTC P0140 | ECM |
| P0141 | DTC P0135 or P0141 | ECM |
| P0171 | DTC P0171 | ECM |
| P0172 | DTC P0172 | ECM |
| P0201 | DTC P0201-P0204 | ECM |
| P0202 | DTC P0201-P0204 | ECM |
| P0203 | DTC P0201-P0204 | ECM |
| P0204 | DTC P0201-P0204 | ECM |
| P0217 | DTC P0217 in Engine Cooling | ECM |
| P0220 | DTC P0220 | ECM |
| P0222 | DTC P0222 | ECM |
| P0223 | DTC P0223 | ECM |
| P0300 | DTC P0300 | ECM |
| P0301 | DTC P0301-P0304 | ECM |
| P0302 | DTC P0301-P0304 | ECM |
| P0303 | DTC P0301-P0304 | ECM |
| P0304 | DTC P0301-P0304 | ECM |
| P0315 | DTC P0315 | ECM |
| P0326 | DTC P0326 | ECM |
| P0327 | DTC P0327 | ECM |
| P0336 | DTC P0336 | ECM |
| P0340 | DTC P0340 | ECM |
| P0341 | DTC P0341 | ECM |
| P0420 | DTC P0420 | ECM |
| P0442 | DTC P0442 | ECM |
| P0446 | DTC P0446 | ECM |
| P0452 | DTC P0452 | ECM |
| P0453 | DTC P0453 | ECM |
| P0455 | DTC P0455 | ECM |
| P0461 | DTC P0461 in Instrument, Panel, Gages and Console | ECM |
| P0462 | DTC P0462 in Instrument, Panel, Gages and Console | ECM |
| P0463 | DTC P0463 in Instrument, Panel, Gages and Console | ECM |
| P0480 | DTC P0480, P0481, P0691, P0692, P0693, P0694, or P1650 (L61) DTC P0480, P0481, P0691, P0692, P0693, P0694, or P1650 (L66) in Engine Cooling | ECM |
| P0481 | DTC P0480, P0481, P0691, P0692, P0693, P0694, or P1650 (L61) DTC P0480, P0481, P0691, P0692, P0693, P0694, or P1650 (L66) in Engine Cooling | ECM |
| P0496 | DTC P0496 | ECM |
| P0506 | DTC P0506 | ECM |
| P0507 | DTC P0507 | ECM |
| P0562 | DTC P0562 in Engine Electrical | ECM |
| P0563 | DTC P0563 in Engine Electrical | ECM |
| P0601 | DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610 | ECM |
| P0602 | DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610 | ECM |
| P0604 | DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610 | ECM |
| P0606 | DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610 | ECM |
| P0607 | DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610 | ECM |
| P0621 | DTC P0621 in Engine Electrical | ECM |
| P0622 | DTC P0622 in Engine Electrical | ECM |
| P0641 | DTC P0641 | ECM |
| P0651 | DTC P0651 | ECM |
| P0700 | DTC P0700 | ECM |
| P1133 | DTC P1133 | ECM |
| P1134 | DTC P1134 | ECM |
| P1137 | DTC P1137 | ECM |
| P1138 | DTC P1138 | ECM |
| P1171 | DTC P1171 | ECM |
| P1516 | DTC P1516 | ECM |
| P1599 | DTC P1599 | ECM |
| P1621 | DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610 | ECM |
| P1640 | DTC P1640 | ECM |
| P1670 | DTC P1670 | ECM |
| P1680 | DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610 | ECM |
| P1681 | DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610 | ECM |
| P1682 | DTC P1682 | ECM |
| P2101 | DTC P2101 | ECM |
| P2119 | DTC P2119 | ECM |
| P2120 | DTC P2120 | ECM |
| P2122 | DTC P2122 | ECM |
| P2123 | DTC P2123 | ECM |
| P2125 | DTC P2125 | ECM |
| P2127 | DTC P2127 | ECM |
| P2128 | DTC P2128 | ECM |
| P2135 | DTC P2135 | ECM |
| P2138 | DTC P2138 | ECM |
| P2176 | DTC P2176 | ECM |
Diagnostic Trouble Code (DTC) List