P0654

DTC P0654

DTC Descriptor

DTC P0654
- Engine Speed Output Circuit

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Diagnostic System Check - Vehicle






Circuit Description

The powertrain control module (PCM) creates the engine speed signal by pulsing the circuit to ground. The engine control module (ECM)/PCM monitors the voltage on the engine speed signal circuit. If the ECM/PCM determines that the voltage is not within the normal operating range, the ECM/PCM sets a DTC.

Conditions for Running the DTC

* The engine speed is greater than 400 RPM.
* The ignition voltage is greater than 6 volts, but less than 18 volts.

Conditions for Setting the DTC

* The ECM/PCM detects that the commanded state of the driver and the actual state of the signal circuit do not match.
* The above condition exists for a minimum of 5 seconds.

Action Taken When the DTC Sets

* The ECM/PCM stores the DTC information in memory when the diagnostic test runs and fails.
* The malfunction indicator lamp (MIL) will not illuminate.
* The ECM/PCM records the operating conditions at the time when the diagnostic test fails. The ECM/PCM stores this information in the Failure Records.

Conditions for Clearing the MIL/DTC

* The DTC becomes history when the conditions for setting the DTC are no longer present.
* A history DTC is cleared after 40 consecutive malfunction-free warm-up cycles.
* The ECM/PCM receives the clear code command from the scan tool.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the ECM/PCM. Install a signal generator and instrument panel tester between the engine speed signal circuit and ground.
2. Ignition ON, set the signal generator to generate a tachometer signal. Verify that the tachometer indicates a RPM reading.

• If no RPM reading is present, test the signal circuit for an open/high resistance, a short to voltage, or a short to ground. If the circuit tests normal, replace the instrument panel cluster (IPC).

3. If all circuits test normal, test or replace the ECM/PCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Control Module References for the ECM/PCM and IPC replacement, setup, and programming