Circuit Description
The powertrain control module (PCM) is the control center of the fuel injection system. The PCM constantly looks at the information from the various sensors. The PCM controls the systems that affect vehicle performance. The PCM also performs the diagnostic function of the system. The PCM can recognize operational problems. The PCM can alert the driver through the malfunction indicator lamp (MIL). The PCM can store DTCs which identify the problem areas in order to aid the technician in making repairs. The PCM uses an electrically erasable programmable read only memory (EEPROM) to house the program information and the calibrations required for the engine, the transmission and the powertrain diagnostics operation. Reprogramming the PCM can update the program of the EEPROM.
Conditions for Setting the DTC
The PCM is improperly programmed.
Action Taken When the DTC Sets
| • | The MIL illuminates. |
| • | The PCM attempts to record the operating conditions at the time this failure is detected. However, since this is an internal PCM failure, this information may or may not be reliable. The Freeze Frame and Failure Records buffers store this information. |
| • | A history DTC is stored. |
Conditions for Clearing the MIL/DTC
| • | A history DTC will clear after 40 consecutive warm up cycles without a fault. |
| • | A scan tool can clear the MIL/DTCs. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
The Powertrain OBD System Check prompts you to complete some of the basic checks and to store the Freeze Frame and Failure Records data on the scan tool if applicable. This creates an electronic copy of the data captured when this DTC set. The scan tool stores this data for later reference.
-
Refer to the latest Techline information for programming procedures.
-
Reprogram the replacement PCM and the perform the Crankshaft Position System Variation Learn Procedure. Refer to the latest Techline procedures for PCM reprogramming .
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | |||
2 | Was the PCM just replaced? | -- | ||
|
Important:: The replacement PCM must be programmed.
Does the DTC reset? | -- | |||
Important: The replacement PCM must be programmed. Is the action complete? | -- | -- | ||
5 |
Does the scan tool indicate that this diagnostic has Ran and Passed? | -- | ||
6 | Check to see if any additional DTCs are set. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to applicable DTC table | System OK |
