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P0566 OBD-II Trouble Code: Cruise Control Off Signal Malfunction

Check Engine Light

P0566 code definition

If the PCM detects a malfunction with the “Off” command in the cruise control system, the P0566 code is stored.

What the P0566 code means

The PCM is part of the cruise control system, which automatically controls the speed when commanded. If there appears to be an issue with the cruise control function, the PCM will run a self-diagnostic test of the entire cruise control system. If an abnormal voltage reading appears in the circuit related to the “off” signal of the cruise control system, the PCM will store the P0566 code.

What causes the P0566 code?

The most likely cause of this code is a failed cruise control switch, particularly caused by spilled liquids or debris build-up in the cruise control buttons.

Other causes may include:

What are the symptoms of the P0566 code?

When the P0566 code is stored, the cruise control will probably be inoperable, and the Check Engine Light will be illuminated. It may take up to three drive cycles before the Check Engine Light comes on.

How does a mechanic diagnose the P0566 code?

After an OBD-II scanner detects the P0566 code, a technician should begin with a visual inspection of all the electrical components of the cruise control system, like wiring and connectors. Any damaged elements should be replaced, reconnected, or repaired as necessary. After this step, and any other attempted repair, the technician should clear the code from the PCM and retest the system, checking that the cruise control works as it should, and that the code does not reappear

If the code reappears, a faulty cruise control switch is the most likely malfunction. After replacing the switch, the mechanic should again clear the code and retest the system, to be sure the issue is resolved.

Common mistakes when diagnosing the P0566 code

The most common misdiagnosis related to the P0566 code is not checking for blown fuses. Blown fuses can cause this code to be stored, and should be inspected before replacing any major parts.

How serious is the P0566 code?

If the P0566 code is being detected, a vehicle will still be drivable. The cruise control may not be usable, but this should not affect any other function of the vehicle. If a fuse is blown, there may be some other minor electrical issues, which may lead to larger repairs in the future. While this code is stored in the PCM, the vehicle may not be able to pass the OBD-II emissions test.

What repairs can fix the P0566 code?

There are many ways that a technician can address a P0566 code detection. They include:

  • Replacing the failed cruise control switch.
  • Repairing any short circuits or open circuits in the cruise control buttons.
  • Repairing shorted or open electrical wiring within the circuitry.
  • Repairing damaged cruise control system connectors.
  • Replacing blown fuses, and repairing the underlying issue that caused the blown fuse.

Need help with a P0566 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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