P0654 Engine RPM Output Circuit Malfunction

OBD2 Code: P0654

Description: Engine RPM Output Circuit Malfunction

Definition: The P0654 code indicates that there is a malfunction in the engine RPM output circuit. This means the Powertrain Control Module (PCM) has detected an issue with the signal being sent from the engine’s tachometer or RPM sensor, which can affect how the vehicle’s systems interpret and use engine speed data.

P0654 – Engine RPM Output Circuit Malfunction

Severity: Moderate

Common Causes

P0654 – Engine RPM Output Circuit Malfunction

Common Causes:

• Faulty engine speed sensor
• Open or short circuit in the engine speed sensor wiring
• Corroded or loose connections in the engine speed sensor circuit
• Defective ECM (Engine Control Module)

 

Common Misdiagnosis

OBD2 Code: P0654

Description: Engine RPM Output Circuit Malfunction

Common Misdiagnosis: Replacing the engine control module (ECM) without checking for wiring issues or faulty sensors.

 

Common Diagnostic Steps

OBD2 Code: P0654

Description: Engine RPM Output Circuit Malfunction

• Check the engine RPM sensor for proper operation and connection.
• Inspect the wiring harness and connectors for damage or corrosion.
• Test the output signal from the engine control module (ECM) to ensure it is within specifications.
• Verify that there are no blown fuses related to the engine RPM circuit.
• Use a scan tool to monitor live data and confirm if the RPM readings are accurate and consistent.
• If applicable, check for any technical service bulletins (TSBs) related to this code for your specific vehicle model.
• If all else fails, consider replacing the ECM as a last resort after confirming all other components are functioning correctly.