Fault code P056B – cruise control “decrease distance” signal malfunction

Fault code P056B is called “Cruise Control “Decrease Distance” Signal Malfunction” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.

Technical description and explained code P056B

This diagnostic trouble code (DTC) is a generic code. Error P056B is considered a generic code because it applies to all makes and models of vehicles. Although the specific repair steps may vary slightly depending on the model.

Fault code P056B – cruise control

Cruise control was designed for comfort, the sole purpose of which is to maintain the vehicle speed set manually by the driver. The driver does not need to control the accelerator pedal. If the car is equipped with an automatic transmission, he can control and adjust the shifts according to the driving conditions in real time.

This code refers to a specific input circuit in the cruise control system. Refer to your service manual to determine which wire or circuit to focus on. Since the circuit with the activation signal may differ from manufacturer to manufacturer.

If the cruise control “reduced distance” signal malfunctions, the control module (PCM) will write code P056B into memory and turn on the warning light on the instrument panel. It is likely that after this, the use of this function will be disabled or will not work properly.

Symptoms of vehicle malfunctions

The main signal that an error P056B has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.

It can also be warning signs such as:

  1. Cruise control lamp on the dashboard is off or on all the time.
  2. Cruise control does not work completely.
  3. Unstable operation of the cruise control.
  4. Some functions do not work as they should (e.g. setting, resuming, accelerating, etc.).
  5. Cruise control turns on but does not work.
  6. Unable to set the cruise control to the desired speed.

The fault code P056B has a low degree of severity, since it does not affect the safety and main assemblies of the car. But, like any electrical problem, it is better to eliminate it, so that the malfunction does not aggravate in the future.

Factors that can cause this error code

The error code P056B can mean that one or more of the following problems have occurred:

  • Cruise control switch is defective.
  • Wiring problem (breakage, chafing, etc.).
  • Faulty connector (e.g. corroded contacts).
  • Debris and dirt are mechanically interfering with the cruise control switch.
  • Cruise control module is defective.
  • Sometimes the cause is a defective PCM module.

How to fix or reset OBD-2 code P056B

Some suggested steps for troubleshooting and fix the error code P056B:

  1. Usually you just need to repair or replace the damaged wires to fix this error.
  2. It is also necessary to check the connection connectors.
  3. You should check for debris that is interfering with the cruise control switch.
  4. If no problems are found, the cruise control module or PCM may be defective.

Diagnose and repair of problems

The first step in the P056B troubleshooting process is to review the Technical Service Bulletins (TSB). For known problems with a particular vehicle.

Next, locate the vehicle’s multi-function cruise control switch and visually inspect it for contamination. The plastic buttons get dirty very easily, causing them to not function properly.

Make sure that the mechanical operation of the switch is smooth and uninterrupted. Any problem should be corrected.

To access the connectors and harnesses of the cruise control switch input circuit, you may need to remove the protective plastic. After that, check the continuity of the wires and connections.

A problem with the PCM module is, in most cases, a last resort to diagnose the P056B error. Given the fact that this can be one of the most expensive repairs, it’s best to trust it to professionals.

On which vehicles does this problem occur most frequently

Fault code P056B can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

  • Audi
  • Chevrolet
  • Citroen
  • Ford
  • Hyundai
  • Nissan
  • Peugeot
  • Volkswagen

Fault code P056B can sometimes be found with other errors. The most common are the following: P0564, P0565, P0566, P0567, P0568, P0569, P056A, P056C, P0570.

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