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

P0564 Cruise Control Multi-Function Input A Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Cruise control buttons are almost always a resistor ladder on one or two signal lines, each button giving its own voltage; the module reading it (GM and Saab from about 2010: the body module; FCA: steering column module or PCM) sends the button state to the engine module over CAN. CARB names cruise control as the example of an emission-neutral diagnosis – it is simply switched off – so GM lists all these codes as type C and Ford as non-MIL: no warning lamp, the engine runs normally. P0564 watches signal line A of the ladder: only voltage windows matching a button or no button are valid. GM sets it when the ratio sits in a gap between windows for over 0.5 s (2014: 2.5 s), the body module in the Saab 9-4X and 9-5 after an invalid voltage for 2 s. Cruise control is locked out for the ignition cycle.

Likely causes

Cruise or steering wheel switch faulty or dirty (moisture, worn contacts)
Clockspring or steering wheel connector with contact resistance
Supply or signal line to the body module open or shorted
Body module

Symptoms

  • Cruise control cannot be switched on or switches off
  • Cruise control locked out
  • No check engine light, engine runs normally

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–450
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

P0578P0579P0580P0581P0575P0585

References: gsi.ext.gm.com, saabwisonline.com, saabwisonline.com, gsi.ext.gm.com.