For 1990-2009 cars

### Circuit Description

The powertrain control module (PCM) used in this vehicle utilizes an electrically erasable programmable read only memory (EEPROM). The EEPROM contains program information and the calibrations required for engine, transaxle, and powertrain diagnostics operation.

The EEPROM is not replaceable. When the PCM is replaced or a calibration update is required, the PCM must be programmed using scan tool or approved Techline equipment. Refer to Powertrain Control Module Programming .

### Conditions for Setting the DTC

The PCM does not contain the correct program required to operate the vehicle.

### Action Taken When the DTC Sets

• | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.

• | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

### Diagnostic Aids

DTC P0602 indicates that the PCM was not programmed. If the PCM cannot be programmed, the only possible repair is PCM replacement. You must program the replacement PCM with the correct software and calibration for the vehicle. Refer to Powertrain Control Module Programming .

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls
2 |

1. Program the PCM with correct software. Refer to Powertrain Control Module Programming .
2. Retest for DTC P0602.

Did DTC P0602 set?

Go to Step 3

System OK

3 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | Go to Diagnostic System Check - Engine Controls | --