Powertrain, generic · Hybrid propulsion

P0C4A Hybrid/EV Battery Pack Coolant Pump A Control Performance

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modePossible

P0C4A says pump A runs electrically but does not achieve its cooling effect. The 2011 Chevrolet Volt fails the test when the pump has been on for over 60 s and the pack inlet coolant temperature has moved by less than 5 °C, rated Type B. GM's bulletin PI0798A (Volt 2011–2015, Ampera 2012, ELR 2014–2016) traces the code after draining and refilling to trapped air, cured by a vacuum purge. Porsche explains for the 2018 Panamera 4 E-Hybrid that the pump reports dry running when its speed rises while current drops, a condition that can need a long stretch of driving before it is logged. Audi (Q4 e-tron 2022) and Bentley (Bentayga and Flying Spur Hybrid, EV speed capped near 48 km/h) also bleed first, Ford reflashes the battery module. FCA's Pacifica Hybrid uses P0C4A for inverter overtemperature instead.

Likely causes

Air trapped in the battery coolant loop, often after a coolant service

Low coolant level or a leak in the low-temperature loop

Worn or failing coolant pump

Battery control module software (Ford/Lincoln 2020 hybrids)

Symptoms

MIL shortly after cooling system work
Electric drive warning, reduced power or capped EV speed
Gurgling noise from the coolant loop

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€80–900

Time0.5–3 h

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

Parts involved

hv battery pack coolant pump awiring harnessbms

References: gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.