P0591Generic code

P0591 Code: Cruise Control Multi-Function Input B Circuit Range/Performance

The P0591 code means the computer sees a fault in the signal from the cruise control switches, with multi-function input B out of its expected range. Cruise control is disabled, and the rest of the vehicle works normally. The steering wheel clockspring is the first suspect.

Severity
Low
Can I keep driving?
Yes, no immediate risk
Estimated cost
$20 to $400
Difficulty
Medium
System
Idle and Speed Control
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

On this page

What the P0591 code means

The cruise control switches, on the steering wheel or on a stalk, send their commands to the computer over one or more wires. Many manufacturers use a single line with a different resistance for each button, and the computer works out which button is pressed from the voltage it measures.

The P0591 code means the computer sees a signal that does not correspond to any button, a signal that stays fixed as if a button were always pressed, or a signal that does not match the second control line. As a precaution, it disables cruise control.

The most frequent cause is the clockspring in the steering wheel, which connects the buttons to the vehicle through a ribbon that wears out as the wheel turns. Another common cause is buttons that are dirty or have had liquid spilled on them.

Always begin with the easy items: fuse, relay and connector. After that, check power, ground and signal with the component connected (using back-probe pins), and last the continuity of every wire to the computer. Replace the component only if all of that checks out.

P0591 code symptoms

  • Cruise control that does not work.
  • Check engine light or cruise control light on.
  • Sometimes the horn or the steering wheel buttons do not work either (clockspring).

Likely causes of the P0591 code

  1. Damaged steering wheel clockspring. The ribbon inside breaks with use.
  2. Steering wheel buttons that are dirty or damaged by spilled liquids.
  3. Control module connector with an intermittent contact.
  4. Brake switch, if it affects the cancel signal.

How to diagnose the P0591 code step by step

  1. Watch the status of each button on the scan tool as you press it. Only the pressed button should change.
  2. Measure the switch resistance in each position and compare it with the manufacturer table.
  3. Check the clockspring if the horn, the airbag light or the steering wheel buttons also fail.
  4. Check the brake switch.

How to fix the P0591 code

  • Replace the clockspring or the steering wheel controls.
  • Clean the contacts of the buttons.
  • Repair the wiring.
  • Clear the code and test cruise control.

Technical reference data

  • Resistor ladder controls: each button gives a different voltage on the same line.
  • Reference values only: check the manufacturer data for your vehicle.

Brand-specific notes

When working at the steering wheel, disconnect the battery and wait a few minutes first. The driver airbag may fire.

P0591 on Ford

The clockspring is a frequent fault on many Ford vehicles.

P0591 on GM

The clockspring is a frequent fault on many GM vehicles.

P0591 on Chrysler

The clockspring is a frequent fault on many Chrysler vehicles.

Frequently asked questions about P0591

Can I drive with the P0591 code?
Yes. It only affects cruise control. The engine, brakes and the rest of the vehicle work as usual, and it is not a safety risk on the road.
What is the clockspring?
It is a ribbon wound inside the steering column that connects the airbag and the buttons to the vehicle even when the steering wheel turns. Once it wears out, the buttons quit.
Is it dangerous to remove the steering wheel?
Yes, because of the airbag. Follow the manufacturer procedure, disconnect the battery and wait before you touch anything.
How much does it cost to fix P0591?
Between $20 and $400. Cleaning a contact or repairing a wire is cheap, while a clockspring or new steering wheel controls cost more.
What does the P0591 code mean?
The P0591 code is a generic OBD2 code for a range or performance fault in cruise control multi-function input B. The computer does not accept the switch signal and turns the system off.
What is the most common cause of P0591?
A worn clockspring in the steering wheel. Dirty buttons and a loose connector follow.

Related codes

Questions about the P0591 code

There are no questions about this code yet. Tell us about your case: vehicle, symptoms and what you have already checked.