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P0339 OBD-II Trouble Code: Crankshaft Position Sensor A Circuit Intermittent

Check Engine Light

P0339 code definition

The P0339 code indicates that the car’s computer has detected a voltage signal from the crankshaft position sensor that exceeds the maximum variation set by the automaker.

What the P0339 code means

The P0339 code means that the car’s computer has detected a problem with the crankshaft position sensor A circuit. In this instance, it has detected a voltage reading that is higher than the maximum set by the manufacturer. Usually, the maximum allowable difference is 10% (between the actual reading and the manufacturer’s setting). Three instances are typically required to trigger the Check Engine light, but the pending code should be stored in the computer.

What causes the P0339 code?

A number of potential causes may lead to the P0339 code being set in the car’s computer, including the following:

  • Damaged crankshaft position sensor
  • Damage to the sensor’s connectors
  • Damage to the sensor’s wiring harness
  • Broken reluctor rings or missing teeth
  • Damage caused by a broken timing belt wrapping around the sensor system
  • Failed PCM (rare)

What are the symptoms of the P0339 code?

Symptoms of the P0339 code can vary considerably depending on the cause, but they include the following:

  • No noticeable symptoms
  • Check Engine light on
  • Reduced fuel economy
  • Reduced engine performance
  • Rough idling
  • Engine misfire
  • Rough acceleration
  • No start

How does a mechanic diagnose the P0339 code?

Diagnosing the P0339 code begins by connecting an OBD-II scanner to the car’s communication port. The mechanic will read the code or codes stored and then clear them. A test drive (if possible) will then need to be made to verify that the codes reset.

Next, the mechanic should inspect the wiring harness and connectors for the crankshaft position sensor. Often, the cause of the problem is actually deterioration of the wiring harness or corrosion of connections due to exposure to engine oil, which can eat through wiring covers. If damage is noted or loose connections are found, these must be replaced or repaired.

If the problem persists, the mechanic will need to test the crankshaft position sensor for operation. This may require removing the sensor from the vehicle to be tested correctly.

Common mistakes when diagnosing the P0339 code

Perhaps the most common mistake made when diagnosing the P0339 code is assuming that the problem is the crankshaft position sensor itself and not performing a complete diagnosis. One of the most common reasons for the P0339 code is actually damage to the wiring harness due to exposure to engine oil.

How serious is the P0339 code?

The P0339 code is actually very serious, even if you are not experiencing any drivability problems. In the case that the problem is caused by damage to the wiring harness or loose connections, the situation will only increase in severity, potentially leaving you stranded during a no start situation. Have the problem diagnosed immediately.

What repairs can fix the P0339 code?

Repairs needed to fix the P0339 code vary depending on the underlying cause, but can include the following:

  • Repairing or replacing damaged wiring
  • Repairing loose connections
  • Repairing oil leaks responsible for degradation of wiring
  • Replacing a failed crankshaft position sensor
  • Replacing broken reluctor rings

Additional comments for consideration regarding the P0339 code

Because there are multiple causes, and a failed sensor is not always the underlying problem, it is crucial for mechanics to perform an in-depth inspection and diagnosis of the problem. This will reduce the chance of performing an expensive repair only to find that it did not address the actual cause of the situation.

Need help with a P0339 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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