For 1990-2009 cars

### 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 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.

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 short to each other. The ECM accomplishes this by pulling the APP sensor 2 signal low momentarily and looking for sensor 1 signal to also be pulled low.

### Conditions for Running the DTC

#### P0601

• | The PCM is in the position of run or start.

• | System voltage is greater than 5-volts.

#### P0602

• | The PCM is in the position of run or start.

• | The controller is identified as a replacement ECM.

#### P0604, P062F

The ignition is in Run or Crank.

#### P0606

• | The ignition switch is in Unlock/Accessory, Run or Crank.

• | The system voltage is greater than 5.23 volts.

#### P0607

• | The ignition switch is in Unlock/Accessory, Run or Crank.

• | The system voltage is greater than 5.23 volts.

• | DTCs P0601, P0602, P0603, P0604, P0606, P0607, P062F, P0641, P0651, P2610 are not set.

#### P060D

• | The ignition switch is in Unlock/Accessory, Run or Crank.

• | The system voltage is greater than 5.23 volts.

• | The processor-related DTC is not set.

#### P2610

• | The ECM is in the state of power off.

• | If the scan fails, set a DTC in the next ignition cycle.

• | The engine coolant temperature is between -40 and +125°C (-40 and +257°F).

### Conditions for Setting the DTC

#### P0601

This diagnostic procedure runs continuously once the ECM detects checkout value is incorrect during at least one sample.

#### P0602

This diagnostic runs continuously once the ECM has not been programmed with ignition On and engine Off during sample.

#### P0603

The ECM checkout value at the last power down does not match the ECM checkout value during the current power up for one sample, this diagnostic runs once per ignition cycle at power up.

#### P0604

The ECM is unable to correctly write and read the random access memory (RAM).

#### 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. 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 second. This DTC runs continuously.

#### P060D

The difference between the main processor (Engine Control Module) indicated accelerator pedal position and the MHC processor indicated accelerator pedal position is greater than 2.5%

#### 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 between 1 and 10 seconds.

• | This diagnostic runs continuously.

#### Phase 2

• | The ECM monitors that the error per second of timer accuracy has not exceeded -20 to +20 percent.

• | This diagnostic runs continuously.

### Actions Taken When the DTC Sets

• | DTCs P0601-P0604, P0606, P060D, and P062F are Type A DTCs.

• | DTC P2610 is a type B DTC.

• | DTC P0607 is a type C DTC.

### Conditions for Clearing the DTC

• | DTCs P0601-P0604, P0606, P060D, and P062F are Type A DTCs.

• | DTC P2610 is a type B DTC.

• | DTC P0607 is a type C DTC.

### Reference Information

Diagnostic Trouble Code (DTC) Type Definitions

### Circuit/System Testing

1. Observe the DTCs in the scan tool

• | If DTC P0602 is set, attempt to program the ECM before replacing the ECM. Refer to Service Programming System (SPS) .

• | If DTC P0602 is reset, replace the ECM.

2. Test the voltage and ground circuits of the ECM for the following:

• | Short

• | Open

• | High Resistance

If all circuits test normal, replace the ECM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Refer to Control Module References for ECM replacement, setup, and programming