P0EF5: Drive Motor C Temperature Sensor Circuit Intermittent/Erratic

P0EF5 covers a drive motor C temperature signal that jumps or drops out for short moments instead of staying wrong. Because of the thermal mass of a traction motor, the winding temperature can only change slowly; a step of many degrees within milliseconds therefore points to the wiring and not to the motor. Loose or corroded pins at the motor connector, leads chafing near moving parts or a cracked sensor lead are typical. No manufacturer documents P0EF5 publicly, and its drive motor A and B siblings P0A2E and P0A34 are not listed in the published Ford and GM tables either; Ford only runs open and short checks on its coil sensors with a 200 ms monitoring window. CARB requires hybrid systems to watch electric motor performance. Warnings that appear and vanish, sometimes with brief power cuts, are typical.

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

Warning lamp that comes and goes
Short power interruptions of motor C, often on rough roads
Jumping motor temperature in the live data

Most likely causes

Loose or corroded pins in the motor connector
Harness chafing at brackets or moving parts
Cracked sensor lead inside the motor that opens with vibration or heat

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
Gently move the wiring with the engine running and watch whether the reading changes.
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 P0EF5 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
E: Subsystem depends on the code range
F5: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0EF5?

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 P0EF5?

The most common causes are: loose or corroded pins in the motor connector; harness chafing at brackets or moving parts; cracked sensor lead inside the motor that opens with vibration or heat.

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.