P0AF8Hybrid/EV Battery System Voltage
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0AF8 compares the battery pack voltage reported by the battery controller with an independent measurement on the high-voltage bus. GM calls it system voltage correlation: with the contactors closed, the 2019 tables fail it when the pack reading differs from the inverter bus voltage by more than 13.95 V, or from the charger bus voltage by more than 14.95 V, 400 of 500 samples at 25 ms, Type A. The 2011 Volt table uses 12 V and Type A, the 2013 eAssist table 5.77 V against the motor controller, Type B. GM's Saturn Vue Hybrid PIP4005A links P0AF8 with P0AFB to a loose negative battery cable, and Volt PIC6089B mentions it with low 12 V system faults. P0AFA and P0AFB judge the voltage level itself.
- What you may notice
- MIL and hybrid or EV warning on
- Battery saver or low battery message
- Intermittent no crank or reduced hybrid power
- Likely causes
- LikelyLoose or arcing high-voltage battery cable connection
- PossiblePack or bus voltage sensing circuit inaccurate
- PossibleLow 12 V supply or loose 12 V power fuse affecting the measuring modules
- RareHigh resistance in a pack fuse or main contactor
- 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 – €3,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.