DTC P0654. Chevrolet Joy 2008

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 P0654 Engine Speed Output Circuit

### Circuit Description

The engine control module (ECM) creates the engine speed output signal by pulsing the circuit to ground. The ECM monitors the voltage on the engine speed output circuit. If the ECM determines that the voltage is out of the normal operating range, a DTC sets.

### Conditions for Running the DTC

The engine is running.

### Conditions for Setting the DTC

The ECM detects an open, short to ground, or a short to voltage on the engine speed output circuit.

### Action Taken When the DTC Sets

DTC P0654 is a Type C DTC.

### Conditions for Clearing the MIL/DTC

DTC P0654 is a Type C DTC.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Engine Controls Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Special Tools

J 33431-C Signal Generator and Instrument Panel Tester

### Circuit/System Verification

With the engine idling for 1 minute, observe the DTC information with a scan tool. DTC P0654 should not set.

### Circuit/System Testing

1. Ignition ON, observe the DTC info with a scan tool. Verify that DTCs P0656, and P1668 are not also set.

⇒ | If DTCs P0656 and P1668 are also set, test the ignition 1 voltage circuit and the ground circuit of the instrument panel cluster (IPC) for an open, short to ground, or high resistance.

⇒ | If the circuits/connections test normal, replace the IPC.

2. Ignition OFF, disconnect the harness connector of the ECM.
3. Install the J 33431-C between the engine speed output circuit and the negative terminal of the battery.
4. Ignition ON, set the J 33431-C to generate a speedometer signal. Verify the tachometer operation.

⇒ | If the tachometer does not operate, test the engine speed output circuit for an open, short to ground, short to voltage, or a high resistance. If the circuit/connections test normal, replace the IPC.

5. If all circuits/connections test normal, replace the ECM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Instrument Cluster Replacement

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