GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 Lucerne 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 DTC P0601, P0602, P0603, P0604, P0606, P0607, P060D, P062F, 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 P0603: Control Module Long Term Memory Reset

DTC P0604: Control Module Random Access Memory (RAM)

DTC P0606:  Control Module Internal Performance

DTC P0607: Control Module Performance

DTC P060D: Control Module Accelerator Pedal Position (APP) System Performance

DTC P062F:  Control Module Long Term Memory 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.

The ECM monitors its ability to read and write to the memory. It also monitors a timing function. The ECM and the TAC processors are used to monitor the TAC system data. Both processors monitor the other processors data to verify that the indicated APP calculation is correct. The ECM performs an intrusive test in order to confirm that the APP signals are not shorted together. The ECM accomplishes this by pulling the APP sensor 2 low momentarily and looking for sensor 1 to also be pulled low.

Conditions for Running the DTC

P0601, P0603

    • The ignition switch is in Run or Crank.
    • The system voltage is more than 5 volts.

P0602

    • The ignition switch is in Run or Crank.
    • The controller is identified as a service replacement ECM.

P0604, P062F

The ignition switch is in Run or Crank.

P0606

    • The ignition switch is in Run or Crank.
    • During test function after key off before the control module powers down.

P0607

    • The ignition switch is in Unlock, Accessory, Run or Crank.
    • The system voltage is more than 5.23 volts.
    • DTCs P0601, P0602, P0603, P0604, P0606, P0607, P062F, P0641, P0651, P2610 are not set

P060D

    • The ignition switch is in Run or Crank.
    • The system voltage is more than 5 volts.

P2610

    • The ignition switch is in the OFF position for at least 1.6 seconds.
    • A low battery voltage or a battery disconnect condition has not taken place. Ignition OFF timer from the previous ignition cycle is stored.

Conditions for Setting the DTC

P0601

The ECM checksum value is incorrect for at least one sample. Each sample is 50 milliseconds. The ECM detects that the check sum value is incorrect for 0.05 second. This diagnostic runs continuous.

P0602

The ECM has not been programmed with Key On and Engine Off for one sample. Each sample is 100 milliseconds. The ECM has not been programmed at Key On and Engine Off for 0.1 second. This diagnostic runs continuous.

P0603

The ECM check sum value at the last power down does not match the ECM check sum value during the current power up for one sample. Each sample is 10 milliseconds. The ECM detects that the check sum value at the last power down does not match the ECM check sum value during the current power up is incorrect for 0.01 second. This diagnostic runs once per ignition cycle at power up.

P0604

The ECM is unable to correctly write and read to and from random access memory (RAM) during the following conditions:

    • Key up initialization for one count. Each count is a read and write sample. Each sample is 100 milliseconds. This portion runs once per ignition cycle.
    • Counter increments by 10 for each sample that does not correctly read and write to the RAM, and decrements by one for each correct sample. No more than 20 counts which do not read and or write correctly. Each read and write sample is 100 milliseconds. This portion runs continuously.
    • Counter increments by 10 for each sample that does not correctly read and write to the Desired Throttle Position RAM and decrements by one for each correct sample. No more than 20 counts which do not read and or write correctly. Each read and write sample is 12.5 milliseconds. This portion runs continuously.

P0606

The ECM detects that the TAC system has a process sequence error, clock error, and 2 motor processor errors, or ETC Internal Processor is not operating correctly. Each test runs in 12.5, 25, 50, 100 and 250 milliseconds. This DTC runs continuously.

P0607

The state of health discrete line between the ETC internal processor and the ECM is not toggling for more than 0.5 seconds. This DTC runs continuously.

P060D

The difference between the main processor (ECM) indicated accelerator pedal position and the MHC processor indicated accelerator pedal position is more than 2.5 percent.

P062F

The ECM did not complete the last electrically erasable programmable read only memory (EEPROM) write event during the last ECM power down. This diagnostic runs once per ignition cycle at power up.

P2610

This diagnostic has 2 tests that may set this DTC:

Phase 1

    • The ECM detects the ignition off timer is less than 1 second at any time.
        OR
    • The ECM detects the ignition off timer is 15 seconds or more if the actual elapsed time is less than 15 seconds.
    • This diagnostic runs continuous.

Phase 2

    • The last ignition off time event increments more than 1.375 seconds or less than 0.8 second for each second.
    • This diagnostic runs continuous.

Actions Taken When the DTC Sets

P0601, P0602, P0603, P0604, P0606, P0607, P060D, or P062F

    • 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.

P2610

    • The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
    • If the diagnostic reports a failure, the control module uses a cold start model based on the engine coolant temperature and intake air temperature at engine start-up. Using the cold start model ensures that the control module is able to determine how much time has elapsed between ignition cycles.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the MIL after 3 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.

Reference Information

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Circuit/System Testing
  1. Observe the DTCs with the scan tool.
    2. ⇒If DTC P0602 is set, attempt to program the ECM before replacing the ECM. Refer to Service Programming System (SPS).
    ⇒If DTC P0602 resets, replace the ECM.
  2. Test the voltage and ground circuits to the control module for the following:
    3. • A short
    • An open
    • High resistance
    ⇒If all circuits test OK, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, programming and setup