GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Optra 🢒 Engine 🢒 Engine Controls - 2.0L (L34 GMDAT) 🢒 DTC P0601, P0602, P0603, P0604, P0605, P0606, P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610

Circuit 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.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC P0601 Control Module Read Only Memory (ROM)
    • DTC P0602 Control Module Not Programmed
    • DTC P0606 Control Module Internal Performance
    • DTC P2610 Control Module Ignition Off Timer Performance

Conditions for Running the DTC

DTC P0601

    • The ignition is ON, with the engine OFF.
    • DTC P0601 runs once an ignition cycle.

DTC P0602

    • The ignition is ON, with the engine OFF.
    • DTC P0602 runs once an ignition cycle.

DTC P0606

    • The ignition is ON, with the engine OFF.
    • The ignition 1 voltage is more than 11 volts.
    • DTC P0606 runs continuously with ignition ON or engine operating.

DTC P2610

    • The ignition is ON or the engine is operating for more than 10 seconds.
    • The non-volatile memory has not reset.
    • DTC P2610 runs once an ignition cycle.

Conditions for Setting DTC

DTC P0601

The ECM detects that the checksum calculation does not match the expected checksum.

DTC P0602

The ECM detects that programming is incomplete for more than 1 second.

DTC P0606

The ECM detects an internal condition for more than 3 seconds.

DTC P2610

The ECM detects a low power counter error for more than 3 seconds.

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.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

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.

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

DTC P0601, P0602, P0606, or P2610

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. Clear the DTCs with a scan tool.
  2. Start the engine and idle the engine until normal operating temperature is reached.
  3. Operate the vehicle within the conditions for setting the DTC as specified in the supporting text.

Did a DTC fail this ignition cycle?

Go to Step 3

Go to Intermittent Conditions

3

Is DTC P0602 set?

Go to Step 4

Go to Step 6

4

Program the engine control module (ECM).

Does DTC P0602 reset?

Go to Step 5

Go to Step 9

5

  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.

Does DTC P0602 reset?

Go to Step 8

Go to Step 9

6

Important: 

   • A low battery condition or a battery that is disconnected and reconnect within 2 minutes may cause this DTC to set.
   • An intermittent condition at the ignition switch may cause this DTC to set.

Is DTC P2610 set?

Go to Step 7

Go to Step 8

7

Test the engine control module (ECM) ignition 1 and battery positive voltage circuits for the following conditions:

    • Open fuses
    • Open circuits
    • Grounded circuits
    • High resistance
    • Intermittent circuit condition

Did you find and correct the condition?

Go to Step 9

Go to Step 8

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. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 10

10

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK