GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Optra - Mexico 🢒 DTC 🢒 DTC P0601, P0602, P0603, P0604, P0605, P0606, P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

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

Circuit/System Description

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

Conditions for Running the DTC

P0601 and P0602

    • The ignition is ON.
    • The DTCs run once an ignition cycle.

P0606

    • The ignition is ON, or the engine is operating.
    • The ignition voltage is greater than 11 volts.
    • The DTC runs continuous when the above conditions are met.

P2610

    • The engine is ON, or the engine is operating for at least 10 seconds.
    • The ignition voltage is greater than 11 volts.
    • The DTC runs once an ignition cycle.

Conditions for Setting the DTC

P0601

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

P0602

The ECM detects that calibration ID does not match the software level.

P0606

The ECM detects an internal condition for more than 2.5 seconds.

P2610

The ECM detects an error with the ignition OFF timer.

Action Taken When the DTC Sets
    • DTCs P0601 and P0602 are Type A DTCs.
    • DTCs P0606 and P2610 are Type B DTCs.

Conditions for Clearing the DTC
    • DTCs P0601 and P0602 are Type A DTCs.
    • DTCs P0606 and P2610 are Type B DTCs.

Reference Information

Description and Operation

Engine Control Module Description

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Circuit/System Testing
  1. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0602 does not fail this ignition cycle.
    2. ⇒If DTC P0602 failed this ignition, reprogram the ECM. Refer to Control Module References . If DTC P0602 resets, replace the ECM.

    Important: 

       • A low battery condition may cause DTC P2610 to set.
       • An intermittent condition at the ignition switch may cause DTC P2610 to set.

  2. Observe the DTC information with a scan tool. Verify that DTCs P0601, P0606, or P2610 do not set this ignition cycle.
    3. ⇒If any of the DTCs P0601, P0606, or P2610 are set this ignition cycle, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming