Powertrain, generic · Hybrid propulsion

P0BC8 Hybrid/EV Battery Pack Cooling Fan 1 Sense Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0BC8 compares the speed fed back by battery cooling fan 1 with what the controller commanded. GM's 2016 and 2018 hybrid tables run two checks. With the fan enabled at 11 to 89 % duty for more than 11 s, the filtered difference between commanded and reported speed must stay inside calibrated limits; large errors fail within seconds, small ones after up to 43 s. With the fan off for more than 20 s, a reported speed above 120 rpm fails in 24 of 32 samples at 250 ms. It is Type B, two trips, and waits while drive or sense circuit codes are active. A dusty or worn fan that cannot reach its speed is the usual cause; a fan turning while commanded off points to a stuck drive. The circuit cases are P0BC7, P0BC9 and P0BCA.

Likely causes

Dust-clogged impeller, blocked intake or worn fan bearing
Fan keeps running while commanded off (stuck drive or relay)
Fan electronics reporting a wrong speed

Symptoms

  • MIL on after two trips
  • Weak airflow or unusual fan noise from the battery intake
  • Reduced electric assist when the pack warms up

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–500
Time0.5–2.5 h

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

Parts involved

battery cooling fanwiring harnessbms

Related codes

P0BC7P0BC9P0BCAP0A82P0A83P0D60

References: gsi.ext.gm.com, gsi.ext.gm.com, patents.google.com.