Description of DTC P06
OBD2 Error Codes

P0654 Engine Speed ​​Output Circuit Malfunction

26.05.2022 /

P0654 – OBD-II Trouble Code Technical Description

Trouble code P0654 indicates that the powertrain control module (PCM) has detected an abnormal (compared to the manufacturer's specification) voltage in the engine speed output circuit.

What does the fault code mean P0654?

Trouble code P0654 indicates that the powertrain control module (PCM) has detected an abnormal voltage in the engine speed output circuit that is different from the manufacturer's specifications. The PCM controls engine speed through several components, including the speed output circuit. It generates an output signal by grounding the circuit through an internal switch known as the “driver”. The PCM constantly monitors each driver, comparing the voltage to set values. If too low or too high voltage is detected in the engine speed output circuit, the PCM sets trouble code P0654.

Fault code P0654

Possible reasons

Some possible causes of the P0654 trouble code:

  • Engine speed sensor malfunction.
  • Problems with the wiring or connectors in the engine speed sensor circuit.
  • Damage or corrosion of contacts on connectors.
  • Engine control module (PCM) malfunction.
  • Electrical problems in the engine control system.
  • Malfunction of external components that affect engine speed, such as the alternator drive belt or fuel tank pump.

A thorough diagnostic test is performed to pinpoint the cause of the P0654 trouble code.

What are the symptoms of a fault code? P0654?

Symptoms for DTC P0654 may include the following:

  1. Check Engine Indicator: When the P0654 code appears, the Check Engine light may come on on your dashboard, indicating there is a problem with the engine management system.
  2. Power Loss: In some cases, a vehicle may experience a loss of power due to improper engine speed control.
  3. Unstable drive: The engine may experience instability, uneven operation, or jerking during acceleration.
  4. Startup problems: The vehicle may have difficulty starting or idling rough due to a malfunctioning engine management system.
  5. Deterioration in fuel economy: Improper operation of the engine management system can result in increased fuel consumption due to inefficient engine operation.

These symptoms may occur to varying degrees depending on the specific cause and the operating conditions of the vehicle.

How to diagnose a fault code P0654?

The following steps are recommended to diagnose DTC P0654:

  1. Checking error codes: Using an OBD-II scanner, check for other error codes in the engine management system. This will help determine if there are other problems that may be affecting the system.
  2. Checking electrical connections: Check the electrical connections and wires associated with the engine speed output circuit. Make sure all connections are secure and free of corrosion.
  3. Resistance test: Measure the resistance in the engine speed output circuit using a multimeter. Compare the values ​​obtained with the manufacturer's specifications.
  4. PCM Driver Check: Check the PCM driver that controls the engine speed output circuit. Make sure it functions correctly and is not damaged.
  5. Checking the sensors: Check the condition of sensors associated with the engine management system, such as the engine speed sensor. Make sure they work properly and are not damaged.
  6. Checking external conditions: Consider external conditions that may affect the operation of the engine management system, such as engine overheating or insufficient voltage in the on-board network.

After completing these steps, you will be able to determine the cause and repair the problem causing the P0654 code. If you do not have sufficient skills to perform diagnostics, it is recommended that you contact a qualified auto mechanic or auto repair shop.

Diagnostic errors

When diagnosing DTC P0654, the following errors may occur:

  • Incorrect cause identification: The error may lie in incorrectly identifying the cause of the problem. For example, symptoms related to other engine management system components may be incorrectly interpreted as the cause of the P0654 code.
  • Insufficient diagnosis: Incorrect or insufficient diagnosis can lead to replacing unnecessary parts or missing the real cause of the problem.
  • Skipping important steps: Skipping certain diagnostic steps, such as checking electrical connections or measuring parameters with a multimeter, may result in incomplete results.
  • Incorrect interpretation of data: Incorrect interpretation of the data obtained during the diagnostic process may lead to an incorrect conclusion about the cause of the malfunction.
  • Ignoring external factors: Ignoring external factors, such as vehicle operating conditions or the impact of external factors on system operation, can also lead to diagnostic errors.

To prevent these errors, it is important to carefully follow diagnostic procedures, consider all possible factors, and have sufficient knowledge and experience in the field of automotive repair and diagnostics. If you are unsure of your skills, it is recommended that you consult a qualified professional.

How serious is the fault code? P0654?

Trouble code P0654 indicates a problem with the engine speed output circuit, which is monitored by the powertrain control module (PCM). While this code is not critical in itself, it can cause the engine to malfunction and cause loss of vehicle performance.

If the problem is not resolved, this may lead to the following consequences:

  • Unacceptable fluctuations in engine speed.
  • Reduced engine performance.
  • Loss of power and poor fuel economy.
  • Possible problems with passing technical inspection or emissions control.

Although P0654 is not an emergency, it is recommended that it be diagnosed and repaired as soon as possible to avoid further problems with your vehicle.

What repair will help eliminate the code? P0654?

To resolve the P0654 code, you must perform the following steps:

  1. Checking electrical connections: The first step is to check all electrical connections, including wires, connectors and pins associated with the engine speed output circuit. Any damaged or oxidized connections must be replaced or repaired.
  2. Replacing the sensor: If the electrical connections are good, the next step may be to replace the engine speed sensor (such as the camshaft position sensor) if it is faulty.
  3. PCM diagnostics: If replacing the sensor does not solve the problem, there may be a problem with the engine control module (PCM) itself. In this case, additional diagnostics of the PCM and, if necessary, its replacement or reprogramming are required.
  4. Grounding check: Check the grounding condition as poor grounding may also cause this error to appear. Make sure all grounds are clean, intact and securely fastened.
  5. Checking power circuits: Check the power circuits associated with the speed sensor and PCM to ensure they are supplying the correct voltage.

After completing these steps, it is recommended to clear the error code and take a test drive to check if the problem has been successfully resolved. If the problem persists, further diagnostics or assistance from a certified auto mechanic may be required.

How to Diagnose and Fix P0654 Engine Code - OBD II Trouble Code Explain

P0654 – Brand-specific information

Trouble code P0654, which indicates a malfunction in the engine speed output circuit. Explanation and examples of application of this error code for some well-known car brands:

It is recommended that you consult the service manual for your specific vehicle make and model for accurate diagnosis and troubleshooting.

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