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P2651 OBD-II Trouble Code: B Rocker Arm Actuator Sys Perf or Stuck Off Bank1

check engine light

P2651 code definition

The P2651 trouble code notes an electrical circuit that is short or open in the rocker arm actuator control circuit for the exhaust camshaft in engine bank 1.

What the P2651 code means

The P2651 code is a generic OBD-II trouble code that detects a problem with the exhaust camshaft (known as the “B”, and placed on the exhaust side of the cylinder head) rocker arm actuator control circuit in engine bank 1. Engine bank 1 is a specific engine bank where the number one cylinder is located. The powertrain control module (PCM) is given a signal from the exhaust camshaft, and when that signal is more than 10 percent off of the manufacturer’s value, the P2651 trouble code will be detected.

What causes the P2651 code?

A few possible causes for the P2651 trouble code include:

  • Low engine oil level or engine oil pressure
  • Malfunctioning oil control valve
  • An open circuit or connector near the oil control valve
  • In very rare cases, a broken PCM

What are the symptoms of the P2651 code?

The P2651 trouble code will be accompanied by the check engine soon Warning Light on the instrument cluster. The car will also likely have a difficult time idling, may experience jerky acceleration, and will have all-around diminished engine performance.

How does a mechanic diagnose the P2651 code?

The P2651 code will be diagnosed with a standard OBD-II trouble code scanner. A reputable technician will use the trouble code scanner to observe the freeze frame data for the P2651 code to assess it, and will also look for any additional trouble codes. The trouble codes will then be reset, and the vehicle restarted. If the P2651 code does not return after being reset, it is assumed that the code was triggered erroneously, though there may be an intermittent error.

If the P2651 code is still detected after the reset, the technician should first inspect the engine oil to see if the levels and pressure are adequate. Following the engine oil inspection, the oil control valve connectors and circuits should be checked, and the mechanic should make sure that the timing indicators are in proper alignment. If no issues are found, the oil control valve and camshaft sensors should be inspected.

Following repair, the trouble codes should be reset.

Common mistakes when diagnosing the P2651 code

The most common mistake that is made when diagnosing the P2651 code is the failure to adhere to the OBD-II trouble code diagnosis protocol. The trouble code diagnosis protocol should always be followed in the proper order, as that ensures that each component is inspected and repaired in the right order.

A common mistake that is made when protocol is not followed is the replacement of certain components when the only issue causing the P2651 is insufficient oil levels or pressure.

How serious is the P2651 code?

The P2651 trouble code will not keep a car from driving, though the engine performance will probably not meet expectations. However, the P2651 code should always be addressed as soon as it is detected, before further damage is caused to the engine.

What repairs can fix the P2651 code?

Some of the repairs that may fix the P2651 trouble code are:

Additional comments for consideration regarding the P2651 code

Every time a component of the vehicle is replaced or repaired, the trouble codes should be reset, and the vehicle restarted. This will tell the mechanic whether the repair or replacement resolved the issue, and can keep the repair as efficient as possible.

While PCM failure can be a cause of the P2651 trouble code, it is very rare, and should never be assumed unless all other options have been inspected. If the PCM does need to be replaced, it will need to be reprogrammed.

Need help with a P2651 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
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