Powertrain, generic (extended)

P2D72 Battery Charging System Negative Contactor D Stuck Open

Check engine lightUsually off

EmissionsNot relevant

Drive cycleNot required

Limp modeNo

P2D72 appears when negative charging contactor D will not close, leaving its path without a return lead; even with plus contactor D pulled in, nothing can be charged. No manufacturer documents P2D72 publicly. Detection can work like GM's Volt test P0D09 for plus contactor A, which expects the charger-side voltage to rise once the contactors are commanded on and fails below 10 V. A missing minus pole and a missing plus pole look the same from that voltage, so the module must use the coil drive states to tell P2D72 from P2D6B. CARB does not require faults to be flagged that cannot be told apart from a failing station. Burnt contacts and a weak coil supply are typical. P2D71 is the welded case.

Likely causes

Minus contactor D does not close mechanically

Weak coil supply or poor ground at contactor D

Module software misattributing a station fault

Symptoms

Charging in the affected mode never begins
Station aborts right after plugging in
Driving unaffected

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€150–4,000

Time1–10 h

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

Parts involved

bcs neg contactor dwiring harnessbms

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