P0590
UniversalCruise Control Multi-Function Input B Circuit Stuck
Medium SeverityThis code indicates that the vehicle's engine control module (ECM) has detected that the cruise control multi-function input B circuit is stuck in an abnormal position or state. This typically means the cruise control system may not engage, disengage, or function correctly due to an electrical signal issue from the control switch.
⚠️ Before You Begin (Safety First)
Always disconnect the battery before working on electrical components. Ensure the vehicle is safely parked and turned off before attempting any repairs. Never attempt to diagnose or repair electrical systems while driving.
Common Symptoms
- Cruise control system will not engage
- Cruise control system disengages unexpectedly
- Cruise control system stuck 'on' (less common but possible)
- Check Engine Light illuminated
Common Causes
- Faulty cruise control multi-function switch
- Wiring issues or damaged connectors in the cruise control circuit
- Short circuit or open circuit in the input B circuit
- Faulty clock spring (if controls are on the steering wheel)
- Defective Powertrain Control Module (PCM) (less common)
Frequently reported on: All Makes
Diagnostic Steps
- Verify the code: Use an OBD-II scanner to confirm P0590 is the active code and check for any other related codes.
- Inspect wiring and connectors: Visually check the wiring harness and connectors leading to the cruise control switch for any signs of damage, corrosion, or loose connections.
- Test the cruise control switch: If accessible, test the functionality of the cruise control switch using a multimeter to check for proper resistance changes or continuity across different switch positions (refer to vehicle-specific repair manual).
- Replace the cruise control switch: If the switch is found to be faulty and is a serviceable part, replace it according to the vehicle's service manual instructions. This may involve removing the airbag module from the steering wheel.
- Clear the code and retest: After any repairs, clear the code with an OBD-II scanner and test the cruise control system to ensure proper operation.
👨🔧 When to Call a Professional
If basic diagnostics and component checks do not resolve the issue, or if you are uncomfortable working with airbag systems (which are often near steering wheel controls), it is best to consult a professional technician for further electrical diagnosis.
Commonly Asked Questions
What does 'Multi-Function Input B Circuit Stuck' mean for my cruise control?
It means the vehicle's computer sees a continuous or abnormal signal from a specific part of the cruise control switch circuit, preventing it from recognizing proper input commands.
Can I still drive my car with a P0590 code?
Yes, you can typically drive your car. The code primarily affects the cruise control system, which is a convenience feature. It does not usually impact the core drivability of the vehicle.
Is replacing the cruise control switch a difficult DIY repair?
It can range from medium to advanced difficulty depending on your vehicle. Many cruise control switches are located on the steering wheel, which often requires careful removal of the airbag module.
Could a bad clock spring cause a P0590 code?
Yes, if the cruise control buttons are on the steering wheel, a faulty clock spring could disrupt the electrical connection for the cruise control circuit, leading to this code.
What is the first thing I should check when I get a P0590 code?
Start by visually inspecting the wiring and connectors around your cruise control switch for any obvious damage, corrosion, or looseness.