P0589 — Cruise Control Multi-Function Input “B” Circuit #

Note: The wording for this code may vary depending on the vehicle manufacturer.

• P0589 — Cruise Control Multi-Function Input “B” Circuit (Generic OBD-II)
• P0589 — Cruise Control Input B Circuit Malfunction (Ford, GM)
• P0589 — Cruise Control Switch B Circuit (Subaru)
• P0589 — Cruise Control Multi-Function Switch Input B (Honda, Toyota)

Summary of Diagnostic Trouble Code P0589 #

Diagnostic Trouble Code (DTC) P0589 indicates a fault detected in the Cruise Control Multi-Function Input “B” Circuit. The cruise control system, sometimes called speed control, allows the driver to maintain a set vehicle speed without pressing the accelerator. Within this system, the multi-function switch (typically found on the steering wheel or column) sends various signals, including “Input B,” to the vehicle’s Engine Control Module (ECM) or Powertrain Control Module (PCM). If the ECM/PCM detects that the signal from Input “B” is missing, shorted, or outside of expected range, it will set code P0589. This code does not refer to a specific switch but to a particular electrical pathway, which may include wiring, connectors, or the switch itself.

Common Symptoms for DTC P0589 #

When code P0589 is present, you might notice one or more of the following issues. These symptoms are generally tied to the cruise control function and may not impact other vehicle operations, but they can be inconvenient and sometimes mask deeper electrical concerns:

• Cruise control will not engage or operate
• Cruise control disengages unexpectedly
• Cruise control indicator light flashes or remains off
• Warning light or check engine light (MIL) illuminated
• Some vehicles may store additional cruise control related codes

Most Likely Causes of Code P0589 #

The causes for P0589 generally revolve around faults in the electrical circuit associated with the cruise control multi-function switch. Some causes are more common than others; here’s a breakdown in typical order of frequency:

1. Faulty cruise control multi-function switch (worn contacts or internal failure)
2. Open, shorted, or corroded wiring/connectors in the Input “B” circuit
3. Defective clock spring (spiral cable in the steering wheel)
4. Faulty cruise control module or relay (if equipped)
5. ECM/PCM malfunction (rare, but possible)

Step-by-Step Diagnostic for P0589 #

Proper diagnosis of code P0589 requires a methodical approach to avoid unnecessary parts replacement and wasted time. Follow these steps to pinpoint the cause:

• Verify the code: Use a professional scan tool to confirm P0589 is active. Check for related codes.
• Inspect cruise control operation: Does the system work at all? Any partial functions?
• Check fuse(s) related to the cruise control and multi-function switch circuits.
• Visually inspect wiring and connectors from the multi-function switch to the control module. Look for damage, corrosion, or loose pins.
• Test the switch: Using a wiring diagram, check Input “B” for continuity and correct voltage with a multimeter as you operate the switch.
• Check clock spring function if the vehicle uses a steering wheel-mounted switch.
• Test control module inputs (if accessible): Ensure the module receives the correct signal from the switch.
• Clear codes and retest after any repair or replacement.

Possible Repairs for P0589 #

Once the root cause is identified, the following repairs are commonly performed to resolve code P0589. The solution should always match the specific fault found during diagnosis:

• Replace faulty cruise control multi-function switch
• Repair or replace damaged wiring/connectors in the Input “B” circuit
• Replace defective clock spring (if necessary)
• Repair or replace faulty cruise control module or relay (if equipped and found defective)
• In rare cases, reprogram or replace the ECM/PCM

Is It Safe to Drive with Code P0589? #

Yes, it is generally safe to drive with code P0589 as this fault affects only the cruise control system and does not impact core engine or braking functions. However, cruise control will be unavailable or unreliable until the issue is fixed. For long highway trips or for drivers who rely on cruise control for comfort, it’s best to address the problem promptly. If other codes or symptoms are present, further investigation is advised.

Vehicles Most Commonly Affected by P0589 #

Code P0589 can affect any modern vehicle equipped with electronic cruise control and OBD-II diagnostics. However, it appears more frequently on certain makes and models, typically where steering wheel or stalk-mounted multi-function switches are common:

• Chevrolet, GMC, and other GM vehicles (2000s–present, especially trucks and SUVs)
• Ford F-Series, Explorer, and related platforms
• Honda Accord, Civic, CR-V (mid-2000s–present)
• Toyota Camry, Corolla, RAV4 (2000s–present)
• Subaru Outback, Forester, Legacy (2005+)

Typical Mistakes and Best Practices with P0589 #

Even experienced technicians can make errors when diagnosing electrical circuit codes like P0589. Here are frequent mistakes and some best practices to avoid costly missteps:

• Replacing the switch without checking wiring: Always verify circuit integrity before replacing parts.
• Overlooking clock spring issues: Remember, steering wheel wiring passes through a clock spring, which is a common failure point.
• Not using the correct wiring diagram for your specific vehicle (always consult OEM documentation).
• Ignoring related codes that could point to a shared wiring problem.
• Best practice: After any repair, clear codes and test the cruise control thoroughly before returning the vehicle to service.

Express FAQ — P0589 #

Here are quick answers to common questions about code P0589:

• Q: Will my car pass inspection with P0589?
  A: In most regions, P0589 alone does not cause an emissions failure, but a check engine light (MIL) can be a reason for rejection in some states. Fix the code if inspection is due.
• Q: Can I reset this code by disconnecting the battery?
  A: Disconnecting the battery may temporarily clear the code, but if the fault is still present, P0589 will return as soon as the vehicle is driven and the cruise control is tested.