Powertrain, generic · Computer and auxiliary outputs

P06F9 Glow Plug Control Module 2 System Voltage

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P06F9 means the supply voltage of glow plug control module 2 is out of range – the counterpart of P052F for module 1. For module 1, Ford's 2023 Power Stroke flags below 6.5 V, above 16.5 V or an open supply after about 1 s; GM's L5P checks the same under P163C (below 6.0 V with ignition above 9 V, or implausible against ignition voltage, 4 s). An FCA bulletin shows P052F together with the glow plug open codes, because without supply no current flows. 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 (P052F). Check main feed, fuses and ground first.

Likely causes

Main feed to glow module 2 open or high-resistance (fuse, fusible link, B+ wire)
Weak battery or discharged auxiliary battery
Module ground corroded
Charging voltage too high

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

DifficultyMediumDIY possible
Parts and labour€30–500
Time0.5–2.5 h

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

Parts involved

glow plug control module 2module power supplymodule ground

Related codes

P052FP06F5P06FAP0562P0563

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