GM Service Manual Online
For 1990-2009 cars only

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 powertrain diagnostics operation.

Unlike the PROM used for past applications, the EEPROM is not replaceable. When the PCM is replaced or a calibration update is required, the PCM must be programmed using approved Techline equipment.

Conditions for Setting the DTC

The ignition is in the crank or the run position.

Conditions for Setting the DTC

The PCM does not contain the correct program required in order 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.

Test Description

The number below refers to the step number on the diagnostic table.

  1. The new PCM must be programmed.

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 the correct software. Refer to Powertrain Control Module Programming .
  2. Retest for DTC P0602.

Did DTC P0602 reset?

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

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