P0590 Cruise control multi-function input "B" circuit stuck

P0590 – OBD-II Trouble Code Technical Description

Cruise control multi-function input "B" circuit stuck

What does the fault code mean P0590?

Code P0590 is a generic OBD-II trouble code indicating a problem in the cruise control system multi-function input "B" circuit. This code indicates an anomaly in the "B" area of ​​the circuit, which is part of the overall circuit that communicates with the powertrain control module (PCM). The cruise control module cooperates with the PCM to automatically control and regulate vehicle speed when cruise control is activated. If the PCM detects an inability to maintain vehicle speed and abnormal voltage or resistance levels in the "B" circuit, a P0590 code will set.

Possible reasons

Code P0590 indicates a malfunction in the speed control switch 2 as detected by the steering column control module (SCCM). Possible causes for this code include:

• Malfunction of the multifunction switch/cruise control switch such as stuck, broken or missing.
• Mechanical problems such as worn or damaged steering column or dashboard parts, water ingress, corrosion and other similar factors.
• Faulty connectors, including corroded contacts, broken plastic parts, or damaged connector housing.
• There is fluid, dirt or contaminants in the cruise control button/switch that may cause incorrect mechanical behavior.
• Problems with the engine control module (ECM), such as water in the computer case, internal shorts, overheating, and other similar problems.

Most often, the P0590 code is associated with defects in the operation of the cruise control switch. This can happen due to a missing electrical circuit, which sometimes occurs if liquid is spilled on the cruise control buttons. This code can also be caused by faulty electrical components, such as damaged or loose wires or corroded connectors.

What are the symptoms of a fault code? P0590?

Code P0590 is usually accompanied by the Check Engine light on your dashboard immediately turning on, although this may not occur in all vehicles. When this code is detected, the cruise control system will likely stop working and problems with blown fuses will often occur.

Symptoms of a P0590 code may include:

• Abnormal vehicle speed with active cruise control
• Cruise control not working
• The cruise control light is on, regardless of the switch position
• Inability to set the desired speed when activating cruise control.

How to diagnose a fault code P0590?

Step №1: Careful inspection of the vehicle's multifunction/cruise control switch is necessary. Dirt and dust can cause plastic buttons and switches to malfunction, preventing them from working properly. Also make sure that the mechanical part of the switch moves smoothly. If you have access to real-time data through an OBD scanner, monitor the electronic operation of the switch.

TIP: Avoid applying cleaning solutions directly to the button. Instead, lightly dampen a clean rag with water, soap and water, or dashboard cleaner and gently clean debris from the switch crevices. Sometimes an air gun can be used to remove debris to avoid damaging components.

Step №2: To access the connectors and wires in the cruise control/multi-function switch circuit, you may need to remove some of the dashboard plastic or covers. When doing this, be careful not to damage the plastic. Working at a comfortable room temperature will make it easier to disassemble and reassemble interior components.

If you can easily reach the connector, you can proceed with the specific troubleshooting steps suggested in the service manual. Testing the switch will likely require a multimeter to record the electrical values. This may include using a switch during recording and/or performing static tests. Detailed instructions can be found in the service manual for your specific vehicle make and model.

Step №3: Problems with the engine control module (ECM) are usually considered the last option in diagnosis. Please note that repairing car electronics can be expensive, so it is recommended to leave the job to a professional.

A standard OBD-II trouble code scanner is used to diagnose the P0590 code. An experienced technician will analyze the image data and evaluate the P0590 code. It will also check for other trouble codes, if any. Then it will reset the codes and restart the car. If the code does not return after a restart, it may have been caused by mistake or a serious malfunction.

If the P0590 code persists, a mechanic will carefully inspect all electrical components in the cruise control circuit. Any blown fuses, short wires or loose connectors should be replaced and damaged components repaired. Carefulness when searching for blown fuses is very important.

Diagnostic errors

The most common error when diagnosing a P0590 code is due to improper adherence to OBD-II trouble code protocol. It is important to carefully follow this protocol, step by step, to ensure efficient and accurate fault detection and avoid unnecessary component replacement. Sometimes complex components are replaced when in fact the root of the problem is blown fuses. An experienced technician always follows a protocol to ensure an accurate diagnosis and avoid unnecessary costs.

How serious is the fault code? P0590?

Trouble code P0590 is serious in the sense that it disables the cruise control system and can make driving difficult. Although this is not a critical problem, it still requires attention and repair to restore the functionality of the cruise control system and ensure a comfortable driving experience.

What repair will help eliminate the code? P0590?

The following repairs may be required to resolve DTC P0590:

1. Replacing a faulty cruise control switch.
2. Replacement of damaged or worn cables in the system.
3. Replacement of corroded or damaged connectors in the system.
4. Replacement of blown fuses in the system.

Additionally, it is important to carefully check the electrical components and wiring to rule out other potential sources of the problem.

What is P0590 Engine Code [Quick Guide]

P0590 – Brand-specific information

Trouble code P0590 may apply to different makes of vehicles. It is associated with problems in the cruise control system and can have different meanings depending on the manufacturer. Here are some of them:

1. Ford – Code P0590 in the Ford engine management system may indicate “Transmission Control Module (TCM) Communication Error.”
2. Chevrolet – In Chevrolet, this code can be deciphered as “Speed ​​control signal A out of range.”
3. Toyota – For Toyota, this may indicate “Speed ​​Control Circuit B Malfunction.”
4. Honda – On Honda, P0590 may mean “Communication Error with Engine Control Module and Transmission Control Module.”
5. Volkswagen – Possible decoding of this code in Volkswagen is “Engine cooling fan circuit interruption.”
6. Nissan – In Nissan, this code may mean “Fan Speed ​​Control Loop Voltage Low.”

Please note that specific transcripts may vary slightly depending on the model and year of the vehicle. It's always best to check with the official repair manual for your specific make and model.