P0AD2: Hybrid/EV Battery Pack Cooling Fan 3 Control Circuit Low

P0AD2 reports that the control signal for battery fan 3 is pulled too low, typically a short to ground on the line between battery controller and blower. Such fans are mostly speed-controlled by a PWM duty cycle, as a Toyota patent on battery fan control explains. No manufacturer publicly documents P0AD2; GM sets the analogous fan 1 code P0A84 when the control voltage stays below 0.257 V with system voltage above 9.1 V, Type B with two trips. The open circuit is P0ACF, a short to voltage P0AD3. CARB requires these electrical checks for battery thermal components. Fan 3 then cannot be driven, and the battery may run warm with limited power.

High severity. Can I keep driving?If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.

Symptoms

Hybrid or EV system warning light, often with check engine light
Electric drive power reduced when the battery gets warm
No fan noise from the battery area when cooling is expected

Most likely causes

Control wire chafed through to body ground
Internal short in fan 3 motor or its electronics
Moisture or spilled liquid in the fan connector
Output stage in the battery controller defective

What to check, in order

Start with the simplest. You can tick off each step.

Read the codes with a hybrid-compatible scanner and write down the freeze frame data
With the connector unplugged, check whether the signal wire is making contact with ground.
Make sure the battery cooling air intake is clean
Check the 12 V auxiliary battery, which can also trigger warnings
Leave any high-voltage measurements to a specialized repair shop

Good to know

Repair difficulty: medium
It can trigger limp mode.
It affects emissions.

What each character of P0AD2 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
A: Hybrid or air and fuel
D2: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0AD2?

If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.

What causes code P0AD2?

The most common causes are: control wire chafed through to body ground; internal short in fan 3 motor or its electronics; moisture or spilled liquid in the fan connector.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.