GM Service Manual Online
For 1990-2009 cars only

Description

This diagnostic applies to internal microprocessor integrity conditions within the control module. This diagnostic also addresses if the control module is not programmed. The following diagnostic trouble codes (DTC)s are diagnosed in this DTC table:

Important: The DTCs listed below are not applicable to all vehicles.

    • DTC P0601 Control Module Read Only Memory (ROM)
    • DTC P0602 Control Module Not Programmed
    • DTC P0603 Control Module Long Term Memory Reset
    • DTC P0604 Control Module Random Access Memory (RAM)
    • DTC P0605 Control Module Programming Read Only Memory (ROM)
    • DTC P0606 Control Module Internal Performance
    • DTC P0607 Control Module Performance
    • DTC P1600 Control Module Long Term Memory Reset
    • DTC P1621 Control Module Long Term Memory Performance

Diagnostic Aids

For complete details on programming the powertrain control module (PCM), refer to Service Programming System (SPS) Description .

Test Description

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

  1. A DTC P0602 indicates the PCM is not programmed.

  2. Attempt to program the PCM. If the PCM fails to program a second time, replace the PCM.

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

Is DTC P0602 set?

Go to Step 3

Go to Step 5

3

Program the PCM. Refer to Powertrain Control Module Programming .

Does DTC P0602 reset?

Go to Step 4

Go to Step 6

4

  1. Ensure that all tool connections are secure.
  2. Ensure that the programming equipment is operating correctly.
  3. Ensure that the correct software/calibration package is used.
  4. Attempt to program the PCM. Refer to Powertrain Control Module Programming .

Does DTC P0602 reset?

Go to Step 5

Go to Step 6

5

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

Go to Step 6

--

6

  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.

Does the DTC run and pass?

Go to Step 7

Go to Step 2

7

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK