Powertrain, generic · Hybrid propulsion

P0C1C Electric/Auxiliary Transmission Fluid Pump Control Module Internal Temperature Sensor Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0C1C is the general circuit fault of the temperature sensor inside the auxiliary pump control module, used when the signal is invalid without fitting the low, high or range checks. No manufacturer documents it publicly. GM's 2016 ELR pump controller monitors its inverter sensor with own codes P1E34 to P1E36 instead, and the Honda CVT pump patent shows why the reading matters: it is the basis for switching the pump off before the board overheats. Without a valid value the controller cannot protect itself, so the pump usually runs restricted or stays off. CARB requires such sensors to be checked for circuit faults. Because the sensor is on the circuit board, the fix is normally the module or the pump assembly. P0C1D to P0C1F are the specific variants.

Likely causes

Temperature sensor or its measuring circuit on the module board faulty
Unstable supply or ground of the pump module distorting the sensor reading
Moisture or fluid inside the module housing

Symptoms

  • Warning lamp or transmission message
  • Start-stop function inactive

Repair estimate

DifficultyHardWorkshop job
Parts and labour€300–1,800
Time1–4 h

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

Parts involved

aux trans pump control module

Related codes

P0C1BP0C1DP0C1EP0C1FP0B0D

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