P0AFEHybrid/EV Battery System Voltage Too Low for Voltage Step Up Conversion
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Many hybrids raise the battery voltage with a step-up (boost) converter before it reaches the inverters; Toyota's second-generation Hybrid Synergy Drive, for example, boosts a pack of around 200 V to 500 V or more. The converter needs a minimum input voltage to reach its target without excessive current. P0AFE is set when the battery-side voltage is below that minimum, so the converter cannot boost properly. No manufacturer documents this exact code publicly; CARB requires hybrid components such as converters to be monitored for functional faults. A deeply discharged or weak pack, a high-resistance connection or a voltage measurement fault are the obvious suspects. Expect reduced electric assist; a low pack voltage is reported separately as P0AFA.
- What you may notice
- Hybrid system warning
- Reduced acceleration and electric assist
- Engine runs more often than usual
- Likely causes
- LikelyPack deeply discharged or weak under load
- PossibleHigh-resistance connection between battery and converter
- RareConverter input voltage measured too low
- 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 – €4,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.