Powertrain, generic · Ignition system or misfire

P0384 Glow Plug Control Module 1 Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P0384 is the counterpart of P0383: the control line from the engine module to the glow plug control module is too high, i.e. shorted to positive. In GM's logic for the 2010/11 Saab 9-5 2.0 TiD the signal terminal should show 9.5–10.5 V; a higher voltage for more than 0.5 s, with ignition on and 9–16 V, sets the code, there without check engine light. Ford's 2023 diesels (6.7 and 3.0 litre) use P0384 differently from the J2012 name, for the supply voltage of the glow plug module: below 6.5 V, above 16.5 V or open, detected in about 1 s – today J2012 has P052F for that. So with Ford, check battery, alternator and the module's supply first. The consequence is missing or irregular preheating or a protective shutdown of the module, with a poor cold start.

Likely causes

Control line chafed against positive or bridged in the connector
Glow plug control module faulty internally (feeding back)
Ford: supply of the module outside 6.5–16.5 V or open (battery, alternator, fuse)
Engine module

Symptoms

  • No or irregular preheating, hard starting when cold
  • Smoke after a cold start
  • Warning lamp depending on the manufacturer

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–450
Time0.5–2 h

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

Parts involved

glow plug control module 1module wiringengine control moduleglow plug supply relay

Related codes

P0383P0670P052FP0683P064C

References: saabwisonline.com, fordservicecontent.com, law.cornell.edu.