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 provide an overview of each diagnostic category.

### DTC Descriptors

DTC P0601: Control Module Read Only Memory (ROM)
DTC P0602: Control Module Not Programed
DTC P0607: Control Module Internal Performance

### Conditions for Running the DTC

#### P0601

• | The ignition is ON, with the engine OFF.

• | The DTCs run once an ignition cycle.

#### P0602

• | The ignition is ON, with the engine OFF.

• | The DTC runs once an ignition cycle.

#### P0607

• | The ignition is ON, with the engine OFF.

• | The ignition voltage is greater than 11 volts.

• | The DTC runs continuously with the ignition ON or engine running.

### Conditions for Setting the DTC

#### P0601

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

#### P0602

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

#### P0607

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

### Action Taken When the DTC Sets

• | DTC P0601 is a Type A DTC.

• | DTC P0602 is a Type B DTC.

• | DTC P0607 is a Type C DTC.

### Conditions for Clearing the DTC

• | DTC P0601 is a Type A DTC.

• | DTC P0606 is a Type B DTC.

• | DTC P2610 is a Type C DTC.

### Reference Information

#### Description and Operation

Engine Control Module Description

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

### Circuit/System Testing

Ignition ON, observe the DTC information with a scan tool.

⇒ | If DTCs P0601, P0602, or P0607 failed this ignition, replace the ECM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming