P0E1D: Hybrid/EV Battery Pack Coolant Pump B Control Performance

P0E1D says pump B accepts its command electrically but the effect the controller looks for does not appear, such as the expected flow, speed or temperature change in its loop. No manufacturer documents P0E1D publicly. The model is pump A on the 2011 Chevrolet Volt: once the pump has run for over 60 s, the pack inlet coolant temperature must have shifted by at least 5 °C, otherwise a Type B code is set. GM bulletin PI0798A traces that pump A code after a drain and refill to trapped air, cleared with a vacuum purge, which is also the first check for pump B after service work. CARB calls for a functional check of battery cooling where feasible. Worn bearings, a clogged inlet or a sensor reading wrongly are further causes. Pump B speed faults may also show as P2CF6 or P2CF7.

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

Check engine light on
Battery or electronics temperatures higher than normal
Gurgling noise from the coolant loop
Power or charging rate limited

Most likely causes

Air trapped in the loop after a coolant service
Worn pump B or debris blocking its impeller or inlet
Low coolant level or leak in the battery loop
Coolant temperature sensor giving an implausible value

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
Compare the reading with other engine data while varying the engine speed.
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 P0E1D means

P: Powertrain: engine and transmission
0: Generic code: same on every make
E: Subsystem depends on the code range
1D: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0E1D?

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 P0E1D?

The most common causes are: air trapped in the loop after a coolant service; worn pump B or debris blocking its impeller or inlet; low coolant level or leak in the battery loop.

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.