Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P0589 Cruise Control Multi-Function Input B Circuit

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. P0589 is the general fault of the second button input B. GM uses it only for one engine variant (LGW): the ratio lies in a gap between valid button windows for over 0.5 s. It is the counterpart of P0564 for input A.

Likely causes

Increased contact resistance shifting button voltages
Button block aged or damp
Clockspring faulty
Module input

Symptoms

  • Cruise or distance control unavailable
  • 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

P0564P0590P0591P0592P0593P0585

References: gsi.ext.gm.com, gsi.ext.gm.com, law.cornell.edu.