Powertrain, generic · Hybrid propulsion

P0D21 Battery Charger A Output Voltage Too Low

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P0D21 is set when the high-voltage output of the on-board charger stays below what the controller expects. GM's Volt and ELR tables split the test in two: during normal charging the charger bus must not fall under 150 V, and when the charger only powers the battery heater, the bus must reach at least 75 % of an expected value calculated from charger current times 70 ohms. Eight failures in ten samples store it as Type B, lighting the MIL on the second trip. Stellantis stores P0D21-00 in the integrated dual charging module (IDCM) of the Jeep Wrangler 4xe from 2021, the Grand Cherokee 4xe from 2022 and the Pacifica Plug-in Hybrid from 2022, with MIL and no charging, and reflashes the IDCM. P0D20 covers a deviation in constant-voltage mode, P0D85 excess voltage.

Likely causes

Charger module software (Stellantis IDCM bulletins)
Failing power stage inside the charger
High resistance or fault in the charger's high-voltage output path or heater load

Symptoms

  • Vehicle does not charge
  • MIL, often after two charging trips
  • Battery not preheated while plugged in during cold weather

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€0–2,500
Time0.5–4 h

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

Parts involved

battery charger awiring harnesshybrid control module

Related codes

P0D20P0D85P0D4EP2E3B

References: gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov, law.cornell.edu.