P0A99Hybrid/EV Battery Pack Cooling Fan 2 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
- P0A99 reports a short to ground on the control circuit of the second battery cooling fan. No manufacturer documents this exact code publicly; Ford's two-fan Escape/Mariner Hybrid packs show that a second fan exists (there with P0A96). CARB requires the outputs used for battery thermal management to be monitored for circuit faults. The fan 1 counterpart P0A84 shows the usual GM logic: with the fan commanded at low duty, an output voltage below about 0.26 V in 16 of 20 samples sets a Type B code. The same approach is to be expected for fan 2. With the output held low the fan may not respond, cooling capacity falls and power may be limited. Open and high faults are P0A96 and P0A9A.
- What you may notice
- Check engine or hybrid warning
- Fan 2 does not run when commanded
- Reduced hybrid power in hot conditions
- Likely causes
- LikelyFan 2 control wire shorted to ground
- PossibleInternal short in fan 2 control input
- RareMoisture or corrosion in the fan 2 connector
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.