P0E4F: Motor Electronics Coolant Pump A Control Circuit Intermittent/Erratic

P0E4F covers coolant pump A of the motor electronics loop, which cools the inverter and drive motor, and sets when the signal exchanged with the pump becomes unstable rather than permanently open or shorted. Ford uses exactly this code in the OBD summaries for its hybrid and plug-in hybrid models of 2015 to 2019: the pump reports back to the module, and P0E4F is stored when that feedback is outside the expected frequency or duty cycle for more than 1 s. The check runs continuously from 500 ms after power-up with 6 to 19 V on the 12 V network, next to P0A05 (no response for over 9.25 s), P0A06 and P0A07 (driver faults) and P0C73 (pump reports an internal fault). Loose pins or moisture in the pump connector are typical; overheat protection may cut power.

Symptoms

• MIL or hybrid system warning
• Power reduction when inverter or motor temperature rises
• Fault may clear itself and return later

Most likely causes

• Loose, corroded or wet pins in the pump A connector
• Chafed command or feedback wire that loses contact intermittently
• Failing electronics inside the pump sending an unstable feedback signal
• Unstable 12 V supply or poor ground at the pump

What to check, in order

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

1. With the engine cold, check the coolant level; never do this when the system is hot
2. Gently move the wiring with the engine running and watch whether the reading changes.
3. Check the actual temperature in live data
4. Make sure the fan comes on when it should
5. Check the thermostat and connector
6. Measure the sensor and replace it if its readings do not make sense

Good to know

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

What each character of P0E4F means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• E: Subsystem depends on the code range
• 4F: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0E4F?

Watch the temperature gauge. If it climbs or a warning appears, stop the car in a safe place and turn off the engine: overheating can cause serious damage.

What causes code P0E4F?

The most common causes are: loose, corroded or wet pins in the pump A connector; chafed command or feedback wire that loses contact intermittently; failing electronics inside the pump sending an unstable feedback signal.

Related codes

• P0A05Motor Electronics Coolant Pump A Control Circuit/Open
• P0A06Motor Electronics Coolant Pump A Control Circuit Low
• P0A07Motor Electronics Coolant Pump A Control Circuit High
• P0C73Motor Electronics Coolant Pump A Control Performance
• P0E50Motor Electronics Coolant Pump B Control Circuit Intermittent/Erratic

Sources

• fordservicecontent.com: OBDSM1901 HEV
• fordservicecontent.com: OBDSM1503 HEV
• law.cornell.edu: 13 CCR 1968.2

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.