Technical Description of OBD-II Trouble Code
The circuit for Cruise Control/Brake Switch A is experiencing a high electrical condition.
What does that mean?
This is a generic diagnostic trouble code (DTC) that applies to OBD-II vehicles, including Chevrolet, GMC, VW, Audi, Dodge, Jeep, Volkswagen, Volvo, Peugeot, Ram, Chrysler, Kia, Mazda, Harley, Cadillac, etc.
The engine control module (ECM) and other modules not only monitor various sensors and switches related to the engine’s proper functionality, but they also ensure that our creature comforts, such as cruise control, are functioning correctly.
While driving, there are many factors that can affect the speed of your vehicle. Some adaptive cruise control (ACC) systems adjust vehicle speeds based on the surrounding conditions, such as passing, slowing for traffic, lane departure, emergency maneuvers, etc.
However, in this case, the fault refers to a malfunction in the cruise control/brake switch “A” circuit. The brake switch is crucial for the operation of the cruise control system. If you use cruise control regularly, it is important to address this issue, as depressing the brake pedal is one way to disable or turn off cruise control. To determine the specific wire, connector, or harness associated with this code, consult the appropriate manufacturer-specific service manual. If you are having trouble finding the necessary information, it is recommended to look for a wiring diagram for the cruise control system, as these diagrams often provide valuable details such as location, specifications, and wire colors.
The P0573 Cruise Control/Brake Switch A Circuit High and related codes (P0571 and P0572) are set when the ECM detects a malfunction within the cruise control/brake switch “A” circuit. In this case, it indicates a high electrical condition within the circuit.
Example of a brake switch and its location:
What is the severity of this DTC?
Typically, the severity of cruise control system issues is considered low. However, in this case, it is moderately severe due to the potential for the brake switch or cruise control to malfunction. The brake switch also plays a crucial role in activating the rear brake lights, which is important for overall driver safety.
What are some of the symptoms of the code?
Symptoms of a P0573 diagnostic code may include:
What are some of the common causes of the code?
Possible causes for this P0573 cruise control code may include:
What are some P0573 diagnostic and troubleshooting steps?
The first step in troubleshooting any malfunction is to consult the Technical Service Bulletins (TSB) for known issues with the specific vehicle.
Advanced diagnostic steps are highly vehicle-specific and may require specialized equipment and knowledge. The following are basic steps, but refer to a vehicle-specific repair guide for detailed instructions.
Basic Step #1
Inspect the brake switch located under the dash, mounted to the brake pedal arm. If the switch is not properly mounted or is completely broken, it should be replaced. Follow the manufacturer’s specific procedures for installing and adjusting the brake switch to avoid damaging the sensor or causing further issues.
Basic Step #2
Verify the circuit involved by referring to a wiring diagram in the service manual. Disconnect one end of the circuit from the brake switch and the other end from the ECM to rule out any faults in the harness. Use a multimeter to perform tests, such as a continuity test, to check for opens, high resistance, etc. Compare the actual values to the manufacturer’s specifications. Inspect the pins in the connectors, switch, and ECM for corrosion or moisture, and clean them if necessary before reconnecting everything.
Basic Step #3
Inspect the ECM (or BCM, if applicable) for any signs of water intrusion, as it may be responsible for monitoring and adjusting the cruise control system. If any issues are suspected, it is recommended to bring the vehicle to a reputable shop or dealer for further inspection.
