Powertrain, generic · Hybrid propulsion

P0D20 Battery Charger A Output Voltage Performance

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P0D20 concerns the on-board charger in its constant-voltage phase, typically near the end of a charge, when it should hold its high-voltage output at a set value. The code means the measured output voltage strays too far from that target. GM's 2011 to 2013 Chevrolet Volt evaluates this in the HPC2/VICM: a deviation of 15 % or more in constant-voltage mode, counted at 100 ms with system voltage above 9 V (2011) or 10.2 V (2012), sets the code after 30 failures in 50 samples, One Trip Type A, so the MIL comes on at once. Later GM tables no longer list it. CARB requires charger faults that stop or slow charging to be detected. Causes lie mostly inside the charger or its voltage sensing. Charging stops or ends early; driving is unaffected. Too low a voltage is P0D21.

Likely causes

Fault in the charger's power stage or voltage control
Inaccurate output voltage measurement
Charge control software in the hybrid control module

Symptoms

  • Charging stops early or the battery does not reach its target level
  • MIL and charging system message

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

P0D21P0D85P0D22P2E3A

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