GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The PCM performs an internal self-test on its Random Access Memory (RAM) or read/write memory. If this self-test fails, this DTC sets.

Conditions for Running the DTC

    • The ignition voltage is more than 10 volts.
    • The ignition is ON for 5 seconds.

Conditions for Setting the DTC

The internal RAM test fails.

Action Taken When the DTC Sets

    • The PCM will illuminate the malfunction indicator lamp (MIL) during the first trip in which the diagnostic test has been run and failed.
    • The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This DTC indicates an internal PCM problem.

DTC P0604 Control Module Random Access Memory

Step

Action

Values

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

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Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Important:: The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .

Did you complete the replacement?

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Go to Powertrain On Board Diagnostic (OBD) System Check

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