P0590
UniversalCruise Control Multi-Function Input B Circuit Stuck
The cruise-control multi-function input lets the vehicle detect a command from a cruise-control control, such as a button or switch. This code means the vehicle detected that input B's circuit remained in a stuck state instead of changing as expected. Cruise control may not work normally, though a stored code may cause no noticeable symptoms if the system is not used.
⚠️ Before You Begin (Safety First)
Do not rely on cruise control until the fault is diagnosed. If cruise control behaves unexpectedly or will not cancel using the normal controls, brake as needed, pull over safely, and have the vehicle inspected. Avoid removing steering-wheel components or probing wiring near airbag parts; those tasks require model-specific procedures.
Common Symptoms
- Cruise control may not engage if the vehicle cannot recognize a required control input.
- One or more cruise-control buttons may not respond as expected if input B is stuck.
- Cruise control may be difficult to operate or cancel normally, depending on how the vehicle uses input B.
- There may be no obvious symptom if cruise control is not being used.
Common Causes
- A cruise-control button or switch may be physically stuck, contaminated, or internally faulty.
- Wiring in the input circuit may be damaged or may have an unintended electrical connection that keeps the signal in one state.
- A loose, corroded, or damaged connector may interfere with the input signal.
- The vehicle's control module or its input circuit may not interpret the signal correctly; diagnosis is needed before considering module replacement.
Diagnostic Steps
- Note whether cruise-control controls work normally and whether the warning or code returns; do not test questionable cruise operation in traffic.
- With the vehicle parked, check that cruise-control buttons move freely and are not held down by dirt or an obstruction.
- Consult the owner's manual for any cruise-related fuse checks, and inspect only accessible fuses using the specified rating; do not substitute a higher-rated fuse.
- Visually inspect accessible wiring and connectors for obvious damage or looseness without removing steering-wheel or airbag components.
- Have the code and live input data checked with equipment and service information appropriate to the vehicle if the fault persists.
When to Call a Professional
Use model-specific service information to identify input B and its expected signal. A technician can compare scan-tool data while operating the cruise controls, inspect the switch and connectors, and test the circuit and controller input with the correct wiring diagram. A fault code alone does not prove the switch needs replacement.
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Commonly Asked Questions
Does P0590 prove the cruise-control switch is faulty?
No. The code identifies a stuck input-circuit condition, which can result from the switch, wiring, connectors, or the vehicle's input electronics. Testing is needed to distinguish them.
Can I drive with P0590?
Cruise control may be unavailable or may not respond normally. Avoid using it until the issue is diagnosed, and stop safely if it behaves unexpectedly or will not cancel normally.
Could the vehicle have this code without noticeable symptoms?
Yes. The code may be stored even if cruise control is not being used or the driver has not noticed a change.
What helps distinguish a stuck switch from a wiring problem?
A technician can compare scan-tool input data while operating the controls, then inspect and test the switch and circuit using vehicle-specific service information.
Browse Available Code Guides
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