Powertrain, generic

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

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

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.

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

Symptoms

Check engine light on
Battery or electronics temperatures rise faster under load
Reduced power or charging rate

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€80–700

Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

hv battery pack coolant pump bwiring harnessbms

References: gsi.ext.gm.com, law.cornell.edu.