P2D74Battery Charging System Negative Contactor D Control Circuit Range/Performance
- Generic OBD-II code · Powertrain
- How the car detects it
- P2D74 says the coil circuit of minus charging contactor D answers commands in an unexpected way, although it is neither open nor shorted. No manufacturer documents P2D74 publicly, and no published GM table has a range test for charge contactor coils. One measure a GM patent proposes is timing: how quickly the coil current climbs to a set level after the driver switches on. A slow rise suggests extra resistance in the circuit or a changed coil. That patent runs its test at key-on or remotely by telematics. CARB asks for a functional check of monitored outputs where feasible. Typical are aged plugs, a degraded coil and a weak driver. P2D73 is the open, P2D75/P2D76 low and high, P2D6D the plus side.
- What you may notice
- Charging via contactor D stops intermittently
- Delayed contactor click when charging starts
- Code reappears after clearing
- Likely causes
- LikelyAged connector adding resistance to the coil circuit
- PossibleCoil of minus contactor D with changed resistance or inductance
- RareOutput stage no longer delivering full current
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.