GM Service Manual Online
For 1990-2009 cars only

Description

This diagnostic applies to internal microprocessor integrity conditions within the engine control module (ECM). This diagnostic also addresses if the ECM is not programmed.

Test Description

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

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

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

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 3

Go to Diagnostic System Check - Vehicle

2

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the DTC information with a scan tool.

Does the scan tool display DTC P0686, P0687, P0689, or P0690?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 3

3

Is DTC P0606 set?

Go to Step 4

Go to Step 5

4

Was DTC P0606 only present after interrogating the vehicle for stored Failure Records or Freeze Frame Data with a scan tool?

Go to Step 9

Go to Step 8

5

Is DTC P0602 set?

Go to Step 6

Go to Step 8

6

Program the engine control module (ECM). Refer to Service Programming System (SPS) in Programming.

Does DTC P0602 reset?

Go to Step 7

Go to Step 9

7

  1. Ensure that all tool connections are secure.
  2. Ensure the programming equipment is operating correctly.
  3. Ensure the correct software and the correct calibration is used.
  4. Attempt to program the ECM. Refer to Service Programming System (SPS) .

Does DTC P0602 reset?

Go to Step 8

Go to Step 9

8

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

Go to Step 9

--

9

  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

Go to Step 10

Go to Step 3

10

Observe the Capture Info with a scan tool.

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

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK