P0589

Universal

Cruise Control Multi-Function Input B Circuit

Definition source: General OBD-II reference catalog
Definition verification: Not independently verified for display.
Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium
Low Severity

The vehicle has detected an issue with the electrical circuit for a cruise-control multi-function input identified as B. That input helps the cruise-control system receive a command or status signal. The code does not identify a failed part by itself, and the exact meaning of input B depends on the vehicle. Cruise control may not work or may work intermittently; some vehicles may show no obvious symptom.

Report an error with this code

⚠️ Before You Begin (Safety First)

If cruise control responds unexpectedly or cannot be cancelled using the vehicle's normal controls, stop using it and pull over safely. Do not drive with cruise control engaged if its operation is unpredictable. Avoid probing wiring in or near the steering wheel; it may be close to airbag components.

Common Symptoms

  • Cruise control may not set or may become unavailable if the system cannot read a required input.
  • Cruise control may operate intermittently if a connection or signal is intermittent.
  • A cruise-control warning light or message may appear, depending on the vehicle.
  • There may be no noticeable symptom if the affected input is not needed during ordinary driving.

Common Causes

  • A damaged, loose, or corroded connector may interrupt the input signal.
  • Wiring in the input circuit may be open, shorted, or damaged.
  • The multi-function switch or another device providing input B may have an internal electrical fault.
  • A control-module input fault is possible, but should be considered only after the circuit and its connections have been checked.

Diagnostic Steps

  1. Note whether cruise control works consistently and whether any warning message or other diagnostic code is present; this helps describe the fault without assuming a part has failed.
  2. With the vehicle parked and switched off, visually check accessible cruise-control switch and wiring connectors for looseness or visible damage. Do not remove steering-wheel trim or probe wiring near airbag components.
  3. Check the owner's manual for any cruise-control fuse information applicable to the vehicle, and inspect only fuses identified there. Replace a fuse only with the specified type and rating; if it fails again, seek diagnosis.
  4. If you have a compatible scan tool, record related codes and any available cruise-control input data. The meaning of input B and the expected data depend on the vehicle.
  5. If the issue remains, have the circuit tested using vehicle-specific wiring information rather than replacing a switch or module based on the code alone.

When to Call a Professional

Use vehicle-specific service information to identify what input B represents and which circuit to test. A technician can check related codes, view cruise-control input data with a scan tool, inspect connectors and wiring, and test the circuit for opens, shorts, or poor connections. Confirm the fault before replacing a switch or control module.

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Commonly Asked Questions

Does P0589 prove the cruise-control switch has failed?

No. It identifies a detected condition in the multi-function input B circuit. Wiring, connectors, the input device, or a control-module circuit may be involved, so testing is needed before choosing a repair.

Can I keep driving with this code?

If the vehicle drives normally and cruise control is not being used, the code alone does not establish that ordinary driving is unsafe. Do not use cruise control if it is unavailable or behaves unpredictably.

What does input B mean?

The code identifies a multi-function input as B, but its specific purpose and circuit layout vary by vehicle. Vehicle-specific service information is needed to identify it.

Could the code appear even if I notice no problem?

Yes. The affected input may not be needed in every situation, or the fault may be intermittent. A scan and circuit checks can help determine whether the condition is current.

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