Powertrain, generic · Ignition system or misfire

P031F Ignition D Control Signal Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Ignition D is one of the control signal lines from the engine module to an ignition module, ignition output stage or group of coils; which cylinders it serves is defined by the manufacturer, not by the code standard. The code concerns the logic-level control signal, not the coil's primary current (that has its own codes, P0351 ff and P2300 ff). P031F means the control line reads high – typically shorted to voltage. No manufacturer using these codes was found; GM reports coil control faults as P0351 ff (open above 30 kΩ, first trip), so the description follows CARB and that analogy. The affected coils fire wrongly or not at all, causing misfire; many modules then shut off injection to those cylinders to protect the catalyst.

Likely causes

Control line shorted to a supply wire
Ignition module or coil faulty
Moisture or corrosion in the connector
Driver stage in the engine module

Symptoms

  • Check engine light on
  • Misfire, jerking, rough idle
  • Loss of power, possibly cylinders shut off
  • Additional misfire codes P0300 ff

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–500
Time0.5–2.5 h

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

Parts involved

ignition control dignition moduleignition wiring

Related codes

P031DP031EP0300P0351P2300

References: law.cornell.edu, gsi.ext.gm.com, newtonnet.co.uk.