Cruise Control Multi-Function Input "B" Circuit High
The P0593 code means the vehicle's onboard diagnostic system has detected: Cruise Control Multi-Function Input "B" Circuit High. This is a low severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $50 - $400 (parts and labor)
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What Are the Symptoms of P0593?
- Check Engine Light on
- Cruise control will not engage or cancels on its own
- Vehicle otherwise drives normally
What Causes P0593? (Most Likely First)
- Open circuit in the switch wiring or clock spring High
- Failed cruise control switch High
- Short to voltage in the input wire Moderate
- Control module input fault Low
Can I Still Drive with P0593?
Yes, but fix soon. P0593 is rated low severity. It is not an immediate stop-driving fault, but it will not clear itself — book the repair rather than ignoring the light.
Frequently Asked Questions
What does P0593 mean?
P0593 means Cruise Control Multi-Function Input "B" Circuit High. The voltage on cruise control switch input "B" is above its normal range, often from an open circuit or a short to voltage.
Can I still drive with this cruise control code?
Yes. It affects the cruise control, not how the vehicle drives. Fix it when convenient, and keep an eye on the Check Engine Light so it does not hide a new code.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P0593?
-
Check which switch or input carries "B" on your vehicle in the service information.
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Watch the cruise switch inputs on a scan tool while pressing each button.
-
Inspect the steering wheel switch connector and, if fitted, the clock spring wiring.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
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