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 Descriptor

DTC P0601 00: Control Module Read Only Memory (ROM)
DTC P0602 00: Control Module Not Programmed
DTC P0604 00: Control Module Random Access Memory (RAM)
DTC P0606 00: Control Module Internal Performance
DTC P0607 00: Control Module Performance
DTC P061A 00: Control Module Long Term Memory Performance
DTC P2610 00: Control Module Ignition Off Timer Performance

### Circuit/System 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 DTC

#### P0601 00

• | The ignition switch is in Run or Crank.

• | The check sum calculation at power-down in the last drive cycle had completely finished.

• | DTC P0601 00 runs once per ignition cycle when the above condition is met.

#### P0602 00

• | The ignition switch is in run or crank.

• | DTC P0602 00 runs once per ignition cycle.

#### P0604 00

• | The ignition switch is in run or crank.

• | The read/write test at power-down in the last drive cycle had completely finished.

• | DTC P0604 00 runs once per ignition cycle when the above condition is met.

#### P0606 00

• | The ignition switch is in the unlock, accessory, run, or crank positions.

• | DTC P0606 00 runs continuously when the above conditions are met.

#### P0607 00

• | The engine is running or cranking.

• | DTC P0607 00 runs continuously when the above condition is met..

#### P0601A 00

• | The system voltage is more than 5.23 V.

• | The ignition is in the unlock, accessory, run, or crank position.

• | DTCs P0601 00, P0602 00, P0604 00, P0606 00, P0607 00, P0641 00, P2610 00 are not set.

#### P2610 00

• | The ECM is powered down.

• | DTC P2610 00 runs once per ignition cycle.

| or

• | The ECM is powered up with the ignition switch in the run or crank position.

• | The engine OFF timer value is less than or greater than an internal reference counter during an 2 s interval.

• | DTC P2610 00 runs continuously when the above conditions are met.

### Conditions for Setting the DTC

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

### Action Taken When the DTC Sets

• | DTCs P0601 00, P0602 00, P0604 00, P0606 00, and P061A 00 are Type A DTCs.

• | DTC P0607 00 is a Type C DTC.

• | DTC P2610 00 is a Type B DTC.

### Conditions for Clearing the DTC

• | DTCs P0601 00, P0602 00, P0604 00, P0606 00, and P061A 00 are Type A DTCs.

• | DTC P0607 00 is a Type C DTC.

• | DTC P2610 00 is a Type B DTC.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Testing for Intermittent Conditions and Poor Connections

• | Connector Repairs

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Testing

1. Observe the DTCs with the scan tool.

⇒ | If DTC P0602 00 is set, attempt to program the K20 Engine Control Module (ECM) before replacing the K20 Engine Control Module (ECM). Refer to Control Module References.

⇒ | If DTC P0602 00 resets, replace the K20 Engine Control Module (ECM).

2. Test the K20 Engine Control Module (ECM) voltage circuits at ECM terminal 21, 50 (X1) and terminal 2, 4, 6 (X2) and test the ground circuits at ECM terminal 20, 35 (X1) and terminal 1, 3, 5 (X2) for the following:

• | A short

• | An open

• | High resistance

⇒ | If all circuits test normal, replace the K20 Engine Control Module (ECM).

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for engine control module replacement, programming and setup