Network, generic

U0695 Lost Communication With Hybrid/EV Battery Pack Coolant Pump B

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

Pump B is a second pump in the battery thermal circuit; what it serves, for instance a parallel branch or a heater or chiller loop, is up to the manufacturer. U0695 is set when that pump stops answering on its data link. No manufacturer documents this code publicly. The public GM tables show a single battery pump only: the 2016 Volt table 16OBDG01 checks its PWM control line at commands between 5 and 95 %, 40 bad readings within 50, sampled every 100 ms, Type B. Hyundai's campaign T4G shows how such pumps fail on the network, using maker-specific codes for the battery and the motor electronics pumps. Pumps like Bosch's PAD2 take PWM or LIN commands and offer diagnostics. Wired faults of pump B are P0E1A to P0E1E.

Likely causes

Wiring or connector of pump B damaged or wet

Pump B electronics or motor failed

Controlling module or software faulty

Symptoms

Battery temperature warning or power limit
Charging power reduced
Hybrid/EV system warning

Repair estimate

DifficultyHardWorkshop job

Parts and labour€100–900

Time1–4 h

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

Parts involved

hv battery coolant pump bvehicle bus wiring

References: gsi.ext.gm.com, static.nhtsa.gov, bosch-mobility.com.