P0E1A: Hybrid/EV Battery Pack Coolant Pump B Control Circuit/Open

P0E1A reports an open or otherwise faulty command circuit for battery coolant pump B, a second electric pump found where the battery loop is split or a separate circuit feeds a chiller or heater. No manufacturer documents P0E1A publicly. For pump A, GM's 2019 tables show how the controller judges such a line by current: while running, below 200 mA or above 3 A is a fault, while off, below 120 µA; failing for 4 s within a 5 s window gives a Type B code. A second pump would usually be monitored the same way. CARB requires every electronic output of battery thermal management to be checked for circuit faults. Usually a wire has parted, a connector has backed out or the pump itself is dead. The low and high cases are P0E1B and P0E1C; supply and speed faults of pump B have their own codes, P2CF4 to 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 rise faster under load
Reduced power or charging rate

Most likely causes

Broken wire in the pump B command circuit
Loose or corroded connector at pump B
Failed electronics inside pump B
Failed pump output in the controlling module

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
Check the continuity of the wire between the component and the control module.
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 P0E1A means

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

Frequently asked questions

Can I keep driving with code P0E1A?

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 P0E1A?

The most common causes are: broken wire in the pump B command circuit; loose or corroded connector at pump B; failed electronics inside pump B.

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.