Technical Description of OBD-II Trouble Code
Malfunction in Cruise Control Off Signal
What does that signify?
This is a generic diagnostic trouble code (DTC) related to the powertrain and is commonly found in OBD-II vehicles equipped with cruise control. This includes vehicles from various manufacturers such as Peugeot, Ford, Nissan, Chevrolet, Hyundai, VW, Audi, Citroen, and others. While the code is generic, the specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
Cruise control offers several functions within the vehicle. It allows the operator to set a specific vehicle speed, which can be automatically maintained using various sensors, switches, modules, and other components. Additionally, the speed can be electronically modified (e.g., “set -” and “resume +”), temporarily adjusted for passing vehicles or unexpected slowing, and more.
Most of the functions mentioned in the description of code P0566, as well as related codes (P0565, P0567, P0568, P0569, P0570, etc.), are contained within a single switch or component. Therefore, locating the mechanical inputs (e.g., buttons, switches, talks) involved should be relatively straightforward. Some common names for this component(s) include Multi-function switch, Steering wheel controls, Cruise control switch, Cruise control module, and Accessory switch.
In the case of this code, the Engine Control Module (ECM) has detected a malfunction within the signal circuit. In simple terms, something has gone wrong with the function mentioned in the description.
When the ECM detects a signal malfunction in one or more of the cruise control functions, it illuminates the Check Engine Light (CEL) with code P0566 or related codes. The use of the affected function(s) will most likely be disabled or behave abnormally.
Code P0566 is triggered when the ECM detects a signal malfunction in the OFF signal of the “On/Off” circuit.
Here is an example of cruise control buttons on a steering wheel:
What is the severity of this DTC?
The severity of this DTC is considered moderately low. Even if the entire functionality of the cruise control system is lost, it is still possible to safely drive the vehicle. However, neglecting any electrical issue for an extended period may lead to further damage, although this is a rare case.
What are some of the symptoms of the code?
Symptoms of a P0566 trouble code may include:
What are some of the common causes of the code?
The causes of this P0566 code may include:
What are some P0566 troubleshooting steps?
Basic Step #1
Start by visually inspecting the cruise control switch/module. Check for missing buttons, buttons stuck due to cola or other substances, loose buttons that do not make proper electrical connections, and any contamination that could potentially damage the buttons. Also, make a note of all malfunctions or abnormalities in the cruise control functions.
Basic Step #2
Verify if the cruise control light comes on in the instrument cluster when the cruise control is manually activated. If not, check if there is a fuse for the circuit and replace any blown fuses with new ones approved by the manufacturer. Refer to the vehicle’s service manual for fuse information.
Basic Step #3
To access the harness to the cruise control switch/module, you will likely need to remove certain dash parts such as the steering column shroud and airbag module in the steering wheel. To pinpoint the specific wire involved in the fault, use a proper wiring harness for your vehicle. These harnesses can vary significantly, so always consult the appropriate service information before performing invasive actions.
Basic Step #4
Ensure that your Anti-lock Braking System (ABS) is in good working order and that no ABS light is illuminated on the dashboard. The ABS system uses various sensors, including speed sensors, which, if malfunctioning, could cause the vehicle’s computers to incorrectly perceive the speed.
