P0606 OBD-II Trouble Code: PCM Processor Fault

Check Engine Light

P0606 code definition

PCM Processor Fault

What the P0606 code means

The Powertrain Control Module is sometimes referred to as the Power Control Module, or the Engine Control Module (ECM); all of these names mean the same thing. The PCM is responsible for monitoring every aspect of the vehicle’s engine and electrical system.

When the vehicle is started up, the PCM will perform a self-check to make sure that all of the engine’s components are operating properly. If the result of this self-check indicates that there is a processor fault in the the PCM, it will store the P0606 diagnostic trouble code.

What causes the P0606 code?

  • PCM wires that are broken, corroded, and/or frayed
  • PCM connectors that are broken, corroded, and/or frayed
  • Faulty PCM ground circuits and/or output devices
  • Faulty Controller Area Network (CAN) bus communication

What are the symptoms of the P0606 code?

  • Check Engine Light is on
  • Anti-lock brake (ABS) light is on
  • Vehicle may stall or shift improperly
  • Vehicle may die when coming to a stop
  • Vehicle may experience misfiring symptoms
  • Increase in fuel consumption
  • Although rare, there may be no felt symptoms

How does a mechanic diagnose the P0606 code?

  • Retrieves freeze frame data using an OBD-II scanner. Doing this will provide information as to when the code was set by the PCM, as well as what likely caused the code to be stored.

  • Visually inspects the wiring and connectors that lead to the PCM for breaks, frayed wiring, and corroded connectors.

  • Retests the system after repairing or replacing damaged wires or connectors. Most likely, the PCM will need to be replaced and/or reprogrammed.

  • Checks with the dealer to see if there are any recalls or if the PCM can be replaced under an emissions warranty.

Common mistakes when diagnosing the P0606 code

The P0606 diagnostic trouble code is difficult to misdiagnose; it is fairly straightforward, and is usually an indication that the PCM needs to be replaced and/or reprogrammed.

However, some of the symptoms are the same as symptoms that would be present for mechanical problems. As a result, it is common that ignition system and/or fuel system components are repaired in error.

How serious is the P0606 code?

The PCM monitors and controls the vehicle’s engine and electrical system. The vehicle will not be able to function without a PCM that is operating properly. For this reason, this code may very well be considered one of the most serious codes.

What repairs can fix the P0606 code?

  • Repairing or replacing any wires that are broken and/or frayed
  • Repairing or replacing any broken and/or corroded connectors
  • Repairing or replacing PCM ground circuits that are faulty
  • Replacing or reprogramming the PCM

Additional comments for consideration regarding the P0606 code

It is important to remember that symptoms of a faulty PCM can be the same symptoms of a faulty mechanical system. The P0606 diagnostic trouble code is simple and straightforward. However, replacing or reprogramming the PCM may need to be done at the dealership.

Need help with a P0505 code?

YourMechanic offers certified 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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