OBD-II Code P0585 – Cruise Control Multi-Function Input A/B Correlation: Understanding the Problem and How to Fix It
OBD-II codes are diagnostic trouble codes that are used to identify problems with a vehicle’s systems. They are generated by the onboard diagnostic system when it detects a fault in any of the components or systems of the vehicle, and the code is used to diagnose and repair the problem. One of the most common OBD-II codes is P0585, which is related to the cruise control system.
Cruise control is a feature that allows a driver to set and maintain a constant speed without having to keep their foot on the accelerator pedal. It is an important convenience feature that can help reduce driver fatigue, improve fuel economy, and even enhance the safety of the vehicle. However, when cruise control malfunctions, it can cause serious problems that need to be addressed immediately.
In this article, we will explain what the OBD-II code P0585 means, how to diagnose the problem, and how to fix it.
Understanding OBD-II Code P0585 – What Does It Mean?
OBD-II code P0585 refers to a problem with the cruise control multi-function input A/B correlation. This code indicates that there is a correlation problem between two circuit inputs in the cruise control system. Specifically, it refers to the relationship between the cruise control switch signals and the signals from the brake light switch.
When the cruise control system is engaged, it automatically turns off when the brake pedal is pressed. This is a safety feature that prevents the vehicle from accelerating when the driver is trying to stop. When the brake light switch is engaged, it sends a signal to the vehicle’s computer to turn off the cruise control system. The cruise control multi-function input A/B correlation is a comparison between these two inputs.
If the OBD-II system detects a discrepancy between these two signals, it will trigger the P0585 code. This means that there may be a problem with the cruise control system that needs to be addressed.
Diagnosing the Problem
The first step in diagnosing the problem is to use an OBD-II scanner to check for any codes that are stored in the vehicle’s computer. If the P0585 code is listed, this indicates that there is a problem with the cruise control system.
The next step is to check the condition of the cruise control switch, the brake light switch, and their related wiring. This can be accomplished by removing the switch, testing it with a multimeter, and inspecting the wiring for any signs of damage or corrosion. If either switch is damaged or worn, it should be replaced.
Another potential cause of the issue is a problem with the vehicle’s brake system. This can be caused by a faulty brake master cylinder, a leak in the brake system, or a malfunctioning brake booster. These issues can also cause the brake pedal to feel soft or spongy, and can even cause the brake warning light to turn on.
There are several other potential causes of the P0585 code, including problems with the cruise control servo, the clockspring, the vehicle speed sensor, or the throttle actuator. These components should be inspected and tested as part of the diagnostic process.
Fixing the Problem
The first step in fixing the problem is to diagnose the root cause of the issue. Once the issue has been identified, the faulty component can be replaced or repaired. If the cruise control switch or the brake light switch is the issue, these parts can usually be easily replaced with little effort. However, if the issue is related to the brake system or another more complex component, it may require a professional mechanic to diagnose and fix the problem.
During the repair process, it may be necessary to clear the OBD-II fault codes from the vehicle’s computer memory. This can be accomplished by disconnecting the battery or using a professional OBD-II scanner.
Frequently Asked Questions:
1. Can I still drive my vehicle with the P0585 code?
While the vehicle may still be drivable, it is not recommended to continue driving with a P0585 code as it can impact the safety and performance of your vehicle. The cause of the code should be diagnosed and repaired as soon as possible.
2. Will replacing the cruise control switch fix the problem?
Replacing the cruise control switch is one possible solution to fixing the P0585 code, but it’s not always the root cause of the issue. A comprehensive diagnostic approach is required to identify and fix the problem before repair is attempted.
3. Can I reset the code without repairing the issue?
Resetting the code without solving the underlying issue will only mask the problem, and the code is likely to reappear. The OBD-II system is designed to trigger fault codes when a problem is detected, and resetting the code does not fix the issue.
4. Can I inspect the cruise control system on my own?
While some basic inspections might be possible for an average person, inspecting and diagnosing the cruise control system can be complicated due to the complexity of modern engines and electronic systems. It is recommended to consult a professional mechanic to ensure a comprehensive diagnosis and repair on your vehicle to fix the issue.
5. Can I still pass an emissions test with a P0585 code?
Since OBD-II codes indicate a malfunction in the vehicle’s emission control systems, passing an emissions test with a P0585 code may be challenging. You must fix the underlying issue before clearing the fault codes with a professional OBD-II scanner and attempting an emissions test again.
Conclusion:
In conclusion, the OBD-II code P0585 is related to the cruise control system’s multi-function input A/B correlation. When triggered, this code indicates that there is a problem with the system that needs to be diagnosed and repaired. The best approach to tackling a P0585 code is a comprehensive diagnosis and repair to identify the underlying issue’s root cause, whether replacing a faulty switch or addressing a problem with the braking system, making sure to fix the problem with the assistance of a professional mechanic when necessary.
Additional resources:
– https://www.obd-codes.com/p0585
– https://www.yourmechanic.com/article/p0585-obd-ii-trouble-code-cruise-control-multi-function-input-a-b-correlation-by-jay-safford
– https://www.autoblog.com/2020/07/01/cruise-control-in-modern-cars/
– https://axleaddict.com/auto-repair/How-do-car-cruise-control-systems-work#:%7E:text=Cruise%20control%20is%20an%20important,they%20get%20distracted%20or%20fatigued.