P0ADFHybrid/EV Battery Negative Contactor Control Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0ADF reports that the drive circuit of the negative main contactor is pulled too low, typically a short to ground in the coil line. GM documents the code in its 2016-19 hybrid tables: control voltage below 5.35 V while the contactor is commanded on, 13 of 16 samples at 12.5 ms (20 of 25 in one 2016 group), Type B with two trips, enabled above about 9 to 10 V on the 12 V system. CARB 1968.2 requires this kind of circuit monitoring for hybrid outputs. Counterparts are P0ADD (open), P0AE0 (high) and, on the positive side, P0ADB. As the contactor cannot close properly, the high-voltage system does not come up and the vehicle will not drive or charge.
- What you may notice
- Vehicle will not enter ready mode or start
- Hybrid or EV warning light and check engine light
- Charging not possible
- Likely causes
- LikelyCoil control wire shorted to ground
- PossibleNegative contactor coil internally shorted
- PossibleMoisture in the battery disconnect unit connector
- RareDriver in the battery controller defective
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.