Powertrain, generic · Computer and auxiliary outputs

P06F4 Stop-Start Mode Lamp Control Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

When the engine module switches a lamp through its own wire, it checks the output driver electrically like other lamp outputs: with the lamp off the line must carry supply voltage, with it on nearly 0 V – GM's MIL driver, for example, flags an open circuit at 200 kΩ or more. It cannot see whether the bulb lights, and on cars that send the lamp command over CAN such faults appear as U codes. P06F4 concerns the indicator showing that stop-start is active or disabled; the code reports a fault in its control circuit. No manufacturer document available to us uses it; the description follows CARB's output check and other lamp circuits. Only the display is affected – the stop-start function itself has its own codes (P06E9, P06EF).

Likely causes

Wire or connector to the indicator open or shorted
Indicator or instrument cluster faulty
Engine module driver stage

Symptoms

  • Stop-start indicator not working or permanently lit
  • Usually no check engine light

Repair estimate

DifficultyEasyDIY possible
Parts and labour€30–250
Time0.3–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

indicator lamp circuitinstrument clusterengine control module

Related codes

P06FFP0650P06EFP06E9

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