Powertrain, generic (extended)

P2DC6 Starter/Generator Phase Z Current Sensor Circuit Range/Performance

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P2DC6 is the plausibility code for the starter/generator's phase Z current sensor. The reading stays within its electrical window but does not match what the controller expects from commanded current and machine state. Care is needed to separate this from a real winding problem: GM's eAssist logic, for example, watches the peak current of each phase as the rotor turns and stores a separate open-phase code when it stays under 9 A although at least 25 A are commanded. A low Z value can thus mean a weak sensor or a phase that truly carries little current. CARB demands rationality faults in their own code, apart from circuit faults. No manufacturer documents P2DC6 publicly. Circuit: P2DC5; Z high and low: P2D94, P2D97; phase correlation: P2DCB.

Likely causes

Phase Z sensor has lost sensitivity or drifted

Real current deviation from a poor phase Z connection or winding fault

Controller software or calibration judging the signal wrongly

Symptoms

Warning lamp, usually after two trips
Reduced starter/generator output or rough automatic restarts

Repair estimate

DifficultyHardWorkshop job

Parts and labour€150–2,000

Time0.5–4 h

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

Parts involved

starter generator phase z current sensorwiring harnessstarter generator control module

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