Description of the P0585 fault code.
OBD2 Error Codes

P0585 Cruise control multi-function input switch "A"/"B" correlation

26.05.2022 /

P0585 – OBD-II Trouble Code Technical Description

Trouble code P0585 indicates a voltage mismatch between the cruise control multi-function switch "A"/"B" correlating inputs.

What does the fault code mean P0585?

Trouble code P0585 indicates a voltage mismatch between the cruise control multifunction switch "A"/"B" correlating inputs. If the voltage at these inputs does not match, the control module (PCM) stores the P0585 code in memory and activates the indicator on the instrument panel. “A” / “B” can represent connectors, wires, or groups of circuits.

Fault code P0585.

Possible reasons

Possible reasons for DTC P0585:

  • Damaged or corroded wires and connectors associated with the multi-function cruise control switch.
  • The multi-function cruise control switch itself is defective or malfunctioning.
  • Problems with the engine control module (PCM), which may be unable to correctly interpret signals from the switch.
  • Electrical fault, including voltage or grounding problems.
  • Other electrical or electronic problems related to the cruise control system.

For an accurate diagnosis and troubleshooting, it is recommended that you contact a qualified technician or service center, especially if you do not have experience working with automotive electrical systems.

What are the symptoms of a fault code? P0585?

Symptoms associated with DTC P0585 may include the following:

  • Cruise control system malfunction: One of the most obvious symptoms can be a malfunctioning or unpredictable cruise control system. This may result in cruise control not engaging or being unable to set or maintain a set speed.
  • Activating the Check Engine Light: Code P0585 will cause the Check Engine Light (Check Engine Light) to be activated on the vehicle's dashboard. This is a warning that there is an error in the system that needs to be checked.
  • Engine instability: In rare cases, incorrect signals from the cruise control multi-function switch may affect engine stability. This may manifest itself as erratic engine operation, loss of power, or other operating anomalies.

How to diagnose a fault code P0585?

The following steps are recommended to diagnose DTC P0585:

  • Use a diagnostic scanner: First, connect the diagnostic scanner to your vehicle's OBD-II port and read the trouble codes. Verify that the P0585 code is indeed present in the system memory.
  • Test the cruise control system: Test the cruise control system to ensure it engages and sets and maintains the set speed. If the cruise control system is not working correctly, there may be a problem causing the P0585 code.
  • Inspect Wires and Connectors: Inspect the wires and connectors associated with the cruise control multifunction switch for damage, breaks, corrosion, or misalignment.
  • Check the status of the cruise control switch: Check the status of the multi-function cruise control switch itself. Make sure it is functioning correctly and has no visible damage.
  • Check Engine Control Module (PCM): Diagnose the Engine Control Module (PCM) to ensure it is functioning correctly and is able to correctly interpret signals from the cruise control switch.
  • Perform Additional Tests: If necessary, additional tests may need to be performed to rule out other possible causes, such as problems with electrical circuits or other system components.

If you are not confident in your vehicle diagnostic or repair skills, it is recommended that you contact an experienced auto mechanic or auto repair shop to diagnose and repair the problem.

Diagnostic errors

When diagnosing DTC P0585, the following errors may occur:

  • Need to Replace Components Without Testing: Sometimes mechanics may immediately suggest replacing the multi-function cruise control switch or other components associated with the system without performing a full diagnosis. This can result in costly replacement of functional components when in reality the problem may be in the wires, connectors, or even the engine control module (PCM).
  • Unchecked electrical problems: Sometimes mechanics may neglect to check the condition of the electrical circuits connecting the cruise control multi-function switch to the PCM. Damaged wires, connectors, or a poor connection may be causing the P0585 code.
  • Limited Diagnostics: Sometimes mechanics may only read fault codes and not perform a full diagnosis of the cruise control system. This may result in missing other issues that may be affecting the operation of that system.
  • Ignoring the Repair Manual: Some mechanics may not pay enough attention to the repair manual or technical bulletins, which may contain additional information about the causes of the P0585 code and diagnostic specifics.
  • Insufficient PCM Check: Sometimes mechanics may overlook the need to check the engine control module (PCM) for problems or software updates that may be related to the trouble code.

To successfully diagnose and resolve a P0585 code, it is important to take a systematic and careful approach and refer to documentation and repair manuals for complete information.

How serious is the fault code? P0585?

Trouble code P0585 is not necessarily serious, but it can cause problems with the vehicle's cruise control system. A fault in this system can render it unusable, which can be especially frustrating on long motorway trips or when you need to maintain a constant speed.

Additionally, the activation of the Check Engine Light can be alarming to the vehicle owner and indicate that there is a problem that needs to be checked and corrected. Since a malfunction may cause the cruise control system to behave unexpectedly or limit its functionality, it is recommended that the problem be corrected as soon as possible to restore normal vehicle operation.

Overall, although the P0585 code is not critical to safety or engine performance, it should be considered an important cruise control system malfunction that requires careful attention and repair.

What repair will help eliminate the code? P0585?


Troubleshooting trouble code P0585 may include the following steps:

  1. Checking and Replacing Wires and Connectors: The first step is to check the condition of the wires and connectors associated with the cruise control multifunction switch. If damage, corrosion or breaks are found, they must be replaced.
  2. Checking and Replacing the Multi-Function Cruise Control Switch: If the wires and connectors are in good condition, the next step is to check the switch itself. If it shows signs of malfunction, it must be replaced.
  3. Engine Control Module (PCM) Test: Diagnose the PCM to ensure it is operating correctly and can correctly interpret signals from the cruise control multi-function switch. In some cases, a PCM software update may be required.
  4. Checking Circuits: Check that the circuits connecting the cruise control switch to the PCM do not have voltage, ground or other electrical abnormalities. Carry out necessary repairs if necessary.
  5. Additional Tests and Diagnostics: If the above steps do not resolve the problem, additional tests and diagnostics may be required to identify other possible causes, such as problems with other cruise control system components or other electrical systems in the vehicle.

It is important to have it diagnosed by a qualified auto mechanic or service center to ensure the problem is properly and completely repaired.

What is P0585 Engine Code [Quick Guide]

P0585 – Brand-specific information

Trouble code P0585 may apply to different makes of vehicles. Here are some of them with transcripts:

In any case, to accurately determine the cause and resolve the P0585 trouble code, it is recommended that you consult an authorized repair manual or a qualified auto mechanic for diagnosis and repair.

Add a comment