Fault code P0654 is called “Engine RPM Output Circuit Malfunction” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P0654
Diagnostic Trouble Code P0654 indicates a problem with the engine speed output circuit. The PCM receives engine speed data from the engine camshaft (CMP) and crankshaft (CKP) sensors.
The crankshaft position sensor (CKP) transmits its position or timing information to the powertrain control module (PCM). This information is normally used for engine RPM. The camshaft position sensor (CMP) also tells the PCM its exact position and timing.
The input signals are used by the transmission control module to monitor the speed and position of the crankshaft and camshaft. Also, this information is used to adjust the ignition advance angle and fuel settings. This is done to adapt to changes in engine load and improve performance.
The data is also used to calculate and monitor engine controllability, then output to the tachometer and controllers.
If the PCM detects a problem in the control of the engine speed output circuit, indicating a malfunction. Then code P0654 will be stored, and the malfunction indicator lamp (MIL) may illuminate.
It may take several failure cycles for the MIL to illuminate, depending on the perceived severity of the fault.
Symptoms of vehicle malfunctions
The main signal that an error P0654 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will light up (the code will be memorized as a fault).
- Other related trouble codes may also be present.
- The speedometer or tachometer is not working, or is malfunctioning.
- The engine is stalling or starting poorly.
The error P0654 is quite serious, as the conditions that caused it to persist may cause damage to the engine. It is recommended to correct the error as soon as possible.
Factors that can cause this error code
The error code P0654 can mean that one or more of the following problems have occurred:
- Dashboard malfunction.
- Open or short circuit in instrument cluster wiring harness.
- Tachometer malfunction.
- Faulty crankshaft sensor (CKP) or camshaft sensor (CMP).
- Corroded electrical connector of CKP/CMP sensors.
- CAN bus may be faulty and have a short to ground or wire breakage.
- Insufficient grounding of control box.
- Open or short circuit between CKP/CMP sensor and PCM.
- Sometimes the cause is the PCM itself.
How to fix or reset OBD-2 code P0654
Some suggested steps for troubleshooting and fix the error code P0654:
- Read all stored data and error codes with an OBD-II scan tool. To find out when and under what circumstances error P0654 appeared.
- Clear the error codes from the computer memory and test-drive the vehicle to find out if the malfunction appears again.
- Check if the dashboard, as well as the wires coming to it, are working properly.
- Check the CKP/CMP sensors as well as the circuits and connectors.
- If the error code appears again, visually inspect the control module (PCM) electrical wiring and connector.
- Measure battery voltage and compare with manufacturer’s specification.
- Check the continuity of the PCM power and ground circuits with a multimeter.
- Evaluate the Control Module (PCM) operation following the vehicle manufacturer’s procedure.
- Clear the error code from the computer memory again, and test drive the vehicle to determine if the problem has been resolved.
Diagnose and repair of problems
To diagnose error P0654, connect the scan tool to the vehicle’s diagnostic port and retrieve all stored codes and data. Make a note of this information in case the code turns out to be intermittent.
Next, you should check the operation of the dashboard and tachometer. After that, visually inspect the connectors and wiring. Look for scratches, scuffs, exposed wires, burn spots, or melted plastic. Disconnect the connectors and carefully inspect the terminals inside the connectors.
Notice if they look burnt or have a green tint indicating oxidation. If you need to clean the terminals, use an electrical contact cleaner and a plastic-bristle brush. Allow to dry and apply electrical grease to the contact areas of the terminals.
Sensor inspection
Perform a visual inspection of the crankshaft position sensor. Look for obvious defects such as a broken wire or a loose, damaged or corroded electrical connector. You may need to remove the sensor to inspect the housing for cracks and other obvious defects to assess overall condition.
Visually inspect the camshaft position sensor for obvious defects. Check for broken wires, loose electrical connections and corrosion. The camshaft position sensor may also need to be removed to assess overall condition.
Some engines may be equipped with an ignition distributor sensor, which also requires visual inspection. If it has failed, it may need to be calibrated with the PCM for proper operation after it is replaced.
If after a complete check, you still continue to get a P0654 code, the PCM may be faulty. But keep in mind that the PCM must be programmed or calibrated for the specific vehicle to work correctly.
On which vehicles does this problem occur most frequently
Fault code P0654 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Buick
- Cadillac
- Chevrolet (Silverado, Tahoe)
- Citroen (C3)
- Fiat
- Ford
- GMC
- Opel
- Peugeot
- GAZelle (Chrysler, ZMZ 405)
- LADA (Priora)
Fault code P0654 can sometimes be found with other errors. The most common are the following: P0320, P0321, P0322, P0323.
