P0593Cruise Control Multi-Function Input B Circuit High
- Generic OBD-II code · Powertrain
- How the car detects it
- Cruise control buttons form a resistor ladder on one or two signal lines, each button giving its own voltage window. FCA uses two lines with offset windows – signal 1 is input A, signal 2 input B – and both must report the same button; GM evaluates the ratio to the reference. Any fault locks out cruise control; CARB treats this as emission-neutral, and GM and Ford set these codes without warning lamp. P0593 means signal line B is too high: GM at a ratio of 1.005–1.035 for over 2 s (short to power), FCA above 4.706 V with about 4.54 V at rest. In FCA's Jeep Wrangler JK recalls it is a typical sign of a dusty clockspring.
- What you may notice
- Cruise control inoperative, possibly airbag warning (Jeep JK)
- Cruise control locked out
- No check engine light
- Likely causes
- LikelyClockspring dirty or faulty
- PossibleLine B shorted to positive or ground open
- PossibleButton block or connector
- RareModule
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.