P0EF3: Drive Motor C Temperature Sensor Circuit Low

P0EF3 is stored when the signal voltage of the drive motor C temperature sensor drops below its valid range. With the usual NTC thermistor on a pull-up resistor, a low voltage stands for an extremely hot winding, so electrically the suspects are a short to ground, a pinched harness or a sensor with an internal short. No manufacturer documents P0EF3 publicly. GM's motor B table for the 2016 Cadillac ELR shows the analogous limit: P0A32 trips once the reading corresponds to more than 184 °C, close to 0 V, after a 90 s warm-up, Type A. Ford's 2019 hybrids fail the motor coil sensor below 0.1 V held for 32 ms. Because the controller cannot tell such a short from real overheating, it derates motor C. P0EF4 covers the high-voltage side.

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

Drive power of motor C reduced immediately
Implausibly high motor temperature in the live data
Warning lamp on

Most likely causes

Signal wire shorted to ground or motor housing
Thermistor shorted internally
Water or coolant in the connector bridging the pins

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: hard
It can trigger limp mode.
It affects emissions.

What each character of P0EF3 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
E: Subsystem depends on the code range
F3: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0EF3?

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 P0EF3?

The most common causes are: signal wire shorted to ground or motor housing; thermistor shorted internally; water or coolant in the connector bridging the pins.

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.