Powertrain, generic · Computer and auxiliary outputs

P06F8 Glow Plug Control Module 2 Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P06F8 means the command line from the engine module to glow plug control module 2 is too high, typically shorted to positive – the counterpart of P0384 for module 1. Note that Ford's 2023 diesels use P0384 differently, for the supply voltage of the glow module (below 6.5 V or above 16.5 V); in J2012 that is P052F, and for module 2 P06F9. No manufacturer document available to us uses a second glow module – Ford's and GM's V8 diesels drive all eight plugs from one; the code suits systems with one module per cylinder bank. The description follows module 1 (P0384). An open line is P06F6, a short to ground P06F7. The plugs of module 2 then heat poorly or not at all, typically on one bank.

Likely causes

Command line shorted to positive or supply
Corrosion in the connector bridging to a B+ pin
Engine module driver shorted

Symptoms

  • Check engine light, possibly glow plug/wait-to-start lamp
  • Hard cold start, long cranking in frost
  • Rough cold idle and white smoke, often one cylinder bank only
  • Usually no symptoms when warm

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–600
Time0.5–3 h

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

Parts involved

glow plug control module 2module wiringengine control module

Related codes

P0384P06F6P06F7P06F9P06F5

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