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 P062B: Control Module Fuel Injector Control Performance
DTC P167A: Control Module HO2S 1 System Performance
DTC P167D: Control Module Ignition Coil Internal Circuit
DTC P2105: Throttle Actuator Control (TAC) System - Forced Engine Shut-down
DTC P2107: Throttle Actuator Control (TAC) Module Internal Circuit
DTC P2610: Control Module Ignition OFF Timer Performance

### 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.

### Conditions for Running the DTCs

#### P0601

• | The ignition switch is in Run or Crank.

• | DTC P0601 runs continuously when the above condition is met.

#### P0602

• | The ignition switch is in Run or Crank.

• | DTC P0602 runs once per ignition cycle.

#### P0603

• | The ignition switch is in Run or Crank.

• | DTC P0603 runs once per ignition cycle.

#### P0604

• | The ignition switch is in Run or Crank.

• | DTC P0604 runs continuously when the above condition is met.

#### P0606

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

• | The system voltage is more than 5.23 volts.

• | DTC P0606 runs continuously when the above conditions are met.

#### P062B

• | The engine is running or cranking.

• | DTC P062B runs continuously when the above condition is met.

#### P167A

• | The engine is running or cranking.

• | DTC P167A runs continuously when the above condition is met.

#### P167D

• | The engine is running or cranking.

• | DTC P167D runs continuously when the above condition is met.

#### P2105

• | The ignition switch is in Run or Crank.

• | DTC P2105 runs continuously when the above condition is met.

#### P2107

• | The ignition switch is in Run or Crank.

• | DTC P2107 runs once per ignition cycle.

#### P2610

• | The ECM is powered down.

• | The intake air temperature is between -40 to +125°C (-40 to +257°F).

• | DTC P2610 runs once per ignition cycle.

### Conditions for Setting the DTCs

The ECM detects an internal failure or incomplete programming for more than 10 seconds.

### Actions Taken When the DTC Sets

• | DTCs P0601, P0602, P0603, P0604, P0606 are Type A DTCs.

• | DTCs P062B, P167A, P167D, P2105, P2610 are Type B DTCs.

• | DTC P2107 is a Type C DTC.

### Conditions for Clearing the MIL/DTC

• | DTCs P0601, P0602, P0603, P0604, P0606 are Type A DTCs.

• | DTCs P062B, P167A, P167D, P2105, P2610 are Type B DTCs.

• | DTC P2107 is a Type C DTC.

### Reference Information

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

### Circuit/System Testing

1. Observe the DTCs with the scan tool.

⇒ | If DTC P0602 is set, attempt to program the ECM before replacing the ECM. Refer to Engine Control Module Programming and Setup .

⇒ | If DTC P0602 resets, replace the ECM.

2. Test the voltage and ground inputs to the ECM for the following:

• | A short

• | An open

• | High resistance

⇒ | If all circuits test normal, replace the ECM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, programming and setup