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 P0606: Control Module Internal Performance
DTC P0607: Control Module Ignition Off Timer Performance
DTC P1607: Control ModulePerformance
DTC P1650: Control Module Performance
DTC P1655: Control Module 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, P0602 and P1607

• | The ignition is ON.

• | The DTCs run once an ignition cycle.

#### P0606, P1650 and P1655

• | The ignition is ON, or the engine is running.

• | The ignition voltage is greater than 11 volts.

• | The DTC runs continuous once the above conditions are met.

#### P0607 and P2610

• | The engine is ON, or the engine is running 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.

#### P0607

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

#### P1607, P1650, and P1655

The ECM detects a low power counter error for more than 3 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, P1655, and P2610 are Type B DTCs.

• | DTCs P0607, P1607, and P1650 are Type C DTCs.

### Conditions for Clearing the DTC

• | DTCs P0601 and P0602 are Type A DTCs.

• | DTCs P0606 and P2610 are Type B DTCs.

• | DTCs P0607, P1607, and P1650 are Type C 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 scan tool DTC information parameter. DTC P0602 should not set.

⇒ | 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. DTCs P0601, P0606, P0607, P1607, P1650, P1655 or P2610 should not set.

⇒ | If 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