Powertrain, generic · Hybrid propulsion

P0BCA Hybrid/EV Battery Pack Cooling Fan 1 Sense Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0BCA means the speed feedback of battery cooling fan 1 is implausibly high. GM's 2016 and 2018 hybrid tables count a failure when the feedback frequency exceeds 290 Hz with the fan enabled at 11 to 89 % duty for more than 8 s and system voltage above 10.2 V; 16 failures in 20 samples at 250 ms set it as Type B, two trips. No real fan reaches that frequency, so the cause is electrical: noise coupled into the feedback line, a line shorted to another signal or to voltage, or fan electronics sending garbage. Check wire routing and grounds before replacing the fan. The low case is P0BC9, speed errors within range P0BC8, an open line P0BC7. While the feedback is untrusted the controller may limit power.

Likely causes

Electrical noise on the feedback line from poor routing or a bad ground
Feedback wire shorted to voltage or another signal
Fan electronics sending an invalid speed signal

Symptoms

  • MIL on after two trips
  • Implausible fan speed reading on the scan tool
  • Possible power reduction

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€40–500
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

P0BC9P0BC8P0BC7P0BCBP0A85P0D62

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