Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there is a problem with the cruise control system in your car. It's like when a remote control button doesn't work right.
The engine control module (ECM) has detected a problem with the input signal from the cruise control multi-function switch, specifically in circuit B.
The P0591 code indicates that the ECM has received an input signal from the cruise control multi-function switch that is out of the expected range or performance parameters. This could be due to a malfunction in the switch, wiring issues, or a problem with the ECM itself.
• Cruise control not working
• Check engine light on
• Intermittent cruise control operation
• Faulty cruise control multi-function switch
• Damaged or corroded wiring or connectors
• Faulty ECM
ECM: Engine Control Module
OBD-II: On-Board Diagnostics II
• Check for any other trouble codes and address them first.
• Inspect the cruise control multi-function switch for proper operation.
• Examine the wiring and connectors for damage or corrosion.
• Replace the faulty cruise control multi-function switch.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Screwdriver set
$100 - $500
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly inspect and maintain cruise control components.
• Keep electrical connections clean and dry.
• Perform routine vehicle diagnostics.
Sensor Issue
• Avoid using cruise control until the issue is resolved.
• Consult a professional mechanic for diagnosis and repair.
Check with your vehicle manufacturer for warranty coverage on cruise control components.
This code has been associated with issues in vehicles with aging cruise control systems, especially in models over 10 years old.
Moderate – The vehicle can be driven, but cruise control functionality is impaired.
Driving with a malfunctioning cruise control system can be unsafe. Ensure repairs are made promptly.
• Vehicle at operating temperature
• Cruise control engaged
The cruise control multi-function switch is typically located on the steering wheel or steering column.
Q: What happens if I ignore this code?
A: Ignoring this code may result in the cruise control not working properly, which can affect driving comfort and safety.
Q: Can I fix this issue myself?
A: If you have automotive repair experience, you might be able to fix it by checking the switch and wiring. Otherwise, it's best to consult a professional.
Pro · Four-system diagnostics
A handheld scanner aimed at engine, transmission, ABS, and airbag diagnostic work.
Chassis and ABS faults usually need a scanner that can read brake-system data directly.
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Universal · Torque wrench
Useful when reassembly torque matters for wheel, suspension, and under-hood fasteners.
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Universal · Drive-on ramps
Helpful for safer access underneath the vehicle during exhaust, EVAP, and underbody inspection work.
Helpful for safer access during underbody inspection work.
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