Powertrain, generic (extended)

P2D9F High Voltage System Voltage High

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P2D9F is the over-voltage case: the DC voltage on the high-voltage network rises above the permitted maximum. Too much voltage stresses capacitors, power semiconductors and cells, so controllers react within milliseconds by cutting regeneration or charging. No manufacturer documents P2D9F publicly. GM's eAssist table of 2013 gives a comparable check under its own code P1AEE: the motor control processor flags system voltage high when its HV sensor reads more than 150 V or a hardware over-voltage flag is set, two trips, Type B. Typical triggers are strong regenerative braking with a full battery, a contactor opening while the motor still generates, or a drifting voltage measurement. Expect reduced regeneration, limited power and a warning light.

Likely causes

Regenerative braking or charging while the battery is already full or cold

Contactor or HV connection opening while the motor generates

Voltage measurement in the inverter or controller reads too high

Voltage limits in control software too tight, update available

Symptoms

Hybrid or EV system warning and check engine light
Little or no regenerative braking, more wear on the friction brakes
Power limited or HV system shut down

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€150–4,000

Time1–6 h

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

Parts involved

hv batterybmshv bus

Related codes

P2D9E P2DA0 P0AFB P0C79 P0AF8

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