P0A99 code meaning
Hybrid/EV Battery Pack Cooling Fan 2 Control Circuit Low
Powertrain system Generic code P0Axx codes Check engine light
What P0A99 means
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.
P0A99 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0A99
- Check engine or hybrid warning
- Fan 2 does not run when commanded
- Reduced hybrid power in hot conditions
Common causes of P0A99
- Most likelyFan 2 control wire shorted to ground
- PossibleInternal short in fan 2 control input
- Less likelyMoisture or corrosion in the fan 2 connector
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hybrid battery cooling fan 2Wiring harnessBms
What each part of P0A99 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| A | Area: hybrid propulsion. |
| 99 | The exact fault in that area. |
What to do next
- Note P0A99 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0A99
What does P0A99 mean?
P0A99 means "Hybrid/EV Battery Pack Cooling Fan 2 Control Circuit Low". P0A99 reports a short to ground on the control circuit of the second battery cooling fan. It is a generic code, so it means the same on every make.
Is it safe to drive with P0A99?
Drive gently and only to a workshop. With P0A99 the car can go into limp mode (reduced power) to protect itself.
Will P0A99 fail an emissions test?
Yes, it can. P0A99 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0A99 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P0A99 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.