Powertrain, generic · Hybrid propulsion

P0D64 Hybrid/EV Battery Pack Cooling Fan Enable Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Besides its speed command, a battery cooling fan can have a separate enable line that switches the fan electronics on. P0D64 means the controller has found this enable output open. GM documents it in its hybrid OBD tables 16OBDG02 to 19OBDG02 under the battery system module, there named fan 1 enable: with the enable commanded off and system voltage above 10.2 V, an output voltage stuck between 1.14 and 2.81 V counts as an open circuit, and 16 failures in 20 samples at 250 ms set it as Type B, MIL after two trips. The fan speed diagnostic P0BC8 is suspended while P0D64 to P0D66 are active. Typical causes are a broken wire or an unplugged fan connector. Without enable the fan stays off, so the battery heats faster and power may be reduced. Short to ground is P0D65, short to voltage P0D66.

Likely causes

Broken enable wire between battery controller and fan
Fan connector unplugged or not latched, often after battery or trim work
Open enable input inside the fan electronics
Enable driver in the battery system module defective

Symptoms

  • Check engine light or hybrid warning after two trips
  • Battery cooling fan does not run
  • Reduced electric assist when the battery gets hot

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–500
Time0.5–2.5 h

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

Parts involved

hv battery cooling fan enablewiring harnessbms

Related codes

P0D65P0D66P0A81P0BC8

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