Powertrain, generic (extended)

P2D2A Hybrid/EV Electronics Coolant Temperature Sensor A/B Correlation

Check engine lightOn
EmissionsNot relevant
Drive cycleRequired
Limp modePossible

Some drives measure the coolant of the inverter and power electronics loop at two points. After a long rest both should read nearly the same, so P2D2A records that sensors A and B disagree by more than the allowed margin; the code does not say which one is wrong. No manufacturer documents P2D2A publicly. GM's 2019 hybrid tables run the idea with one sensor and other references under P0CEF: after at least 3,600 s with compressor, pump and propulsion off, the electronics coolant reading must stay within 27 °C of outside air or transmission fluid, or 28 °C of a refrigerant-based value (Type B). CARB requires inputs of inverter thermal management to be monitored.

Likely causes

One of the two sensors has drifted
Added resistance in a connector or wire shifting one reading
Air pocket at one sensor after coolant service
Replacement sensor with a different characteristic

Symptoms

  • Hybrid or EV system warning
  • Electronics coolant pump runs more often or at full speed
  • Possible power reduction to protect the inverter

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–450
Time0.5–2.5 h

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

Parts involved

hybrid electronics coolant temp sensor ahybrid electronics coolant temp sensor bhybrid control module

Related codes

P0CEFP2B21P0CEEP2B20P2D2B

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