Powertrain, generic · Vehicle speed, idle control and auxiliary inputs
P0592 Cruise Control Multi-Function Input B Circuit Low
Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo
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. P0592 means signal line B is too low: GM (engine variant LGW) at a ratio of 0–0.185 for over 2 s, a short to ground or open circuit; FCA treats signal 2 below 0.784 V as circuit low.
Likely causes
Line B shorted to ground (steering wheel, clockspring)
Button block faulty or damp
Corroded connector
Module
Symptoms
- Cruise control and distance or mode buttons inoperative
- Cruise control locked out
- No check engine light
Repair estimate
DifficultyMediumWorkshop job
Parts and labour€50–450
Time0.5–2 h
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
cruise control switchclockspringswitch wiringbody control module
Related codes
References: gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.