GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC C Sierra - 2WD 🢒 Engine 🢒 Engine Controls - 6.6L 🢒 DTC P0601, P0602, P0603, P0604, P0605, P0606, P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610

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 (DTCs) 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 P1621 Control Module Long Term Memory Performance
    • DTC P1683 Control Module Ignition Off Timer Performance

Test Description

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

  1. A DTC P0602 indicates the engine control module (ECM) is not programmed.

    2.

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

DTC P0601-P0607, P1600, P1621, or P1683

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

Does DTC P0602 set?

Go to Step 3

Go to Step 5

3

Program the ECM.

Does DTC P0602 reset?

Go to Step 4

Go to Step 6

4

  1. Ensure that all tool connections are secure.
  2. Ensure the programming equipment is operating correctly.
  3. Ensure the correct software/calibration package is used.
  4. Attempt to program the ECM.

Does DTC P0602 reset?

Go to Step 5

Go to Step 6

5

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

Go to Step 6

--

6
  1. Use a scan tool to clear DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start and run 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 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