P0A84 code meaning
Hybrid/EV Battery Pack Cooling Fan 1 Control Circuit Low
Powertrain system Generic code P0Axx codes Check engine light
What P0A84 means
The controller detects a short to ground on the control output of battery cooling fan 1. GM tests it while the fan is commanded at low duty: a circuit voltage below about 0.26 V counts as a failure, and 16 fails in 20 samples at 250 ms set a Type B code (MIL after two trips). Another GM hybrid program detects it through the output stage status flag (20 of 25 samples). Mitsubishi lists P0A84 in the BMU and PHEV ECU of the 2018–20 Outlander PHEV among codes caused by a frozen battery heater relay, so meaning can differ by maker. Open and high faults are P0A81 and P0A85. With the output pulled low the fan may not respond, the pack warms up and power can be reduced.
P0A84 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 P0A84
- Check engine or hybrid warning after two trips
- Battery cooling fan does not follow commands
- Reduced hybrid power when the pack gets warm
Common causes of P0A84
- Most likelyFan control wire chafed and shorted to ground
- PossibleInternal short in the fan's control input
- Less likelyMoisture or corrosion in the fan connector
- Less likelyDefective output stage in the controller
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Battery cooling fanWiring harnessBms
What each part of P0A84 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. |
| 84 | The exact fault in that area. |
What to do next
- Note P0A84 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 P0A84
What does P0A84 mean?
P0A84 means "Hybrid/EV Battery Pack Cooling Fan 1 Control Circuit Low". The controller detects a short to ground on the control output of battery cooling fan 1. It is a generic code, so it means the same on every make.
Is it safe to drive with P0A84?
Drive gently and only to a workshop. With P0A84 the car can go into limp mode (reduced power) to protect itself.
Will P0A84 fail an emissions test?
Yes, it can. P0A84 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 P0A84 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P0A84 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.