Powertrain, generic (extended)

P2BDC Motor Electronics Coolant Temperature Sensor C Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2BDC reports a general fault in the circuit of coolant temperature sensor C, a third measuring point that some drives use in the loop cooling the inverter, converter and motor. The code stands for a signal the module cannot use without assigning it to the low, high or plausibility codes P2BDE, P2BDF and P2BDD. No manufacturer documents P2BDC, or a third sensor of this kind, publicly. As a guide to what such a module accepts as a valid signal, GM's 2011 Volt tables keep their single electronics coolant sensor between 2 % and 98 % of the 5 V reference and treat an exit from that window in 16 out of 20 readings, one every 250 ms, as a Type B fault. CARB requires circuit checks on these inputs. Without the value, cooling falls back to safe defaults.

Likely causes

Poor contact at the sensor C connector
Chafed or broken wiring between sensor C and the module
Defective sensor C
Fault on a 5 V reference or sensor ground shared with other sensors

Symptoms

  • Warning lamp for the hybrid or drive system
  • Fan and electronics pump running at high output as a precaution
  • Possibly reduced electric power

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–500
Time0.5–2.5 h

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

Parts involved

motor electronics coolant temp sensor cwiring harnesshybrid control module

Related codes

P2BDDP2BDEP2BDFP2BD8P0CF0P0CF1

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