Powertrain, generic · Hybrid propulsion

P0CE9 Hybrid/EV Electronics Coolant Pump A Control Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

The hybrid controller checks the control line of the electric pump that moves coolant through the power electronics loop, which in GM's Volt and ELR serves the inverter module and the high-voltage charger. GM tables from 2011 to 2016 fail it when the output driver reports an open line or a short to ground or voltage in 16 of 20 samples at 250 ms. The 2019 HPC2 table measures line current instead: below 200 mA or above 3 A while the pump is commanded on, below 120 µA while it is off, for 4 s within a 5 s window. All variants are Type B, two trips. Audi logs P0CE900 on the e-tron and Q8 e-tron in thermal management unit 00C5. P0CEB and P0CEC split the fault into low and high, P0CEA covers pump function. With the pump idle, inverter and charger heat up and power is reduced.

Likely causes

Open or chafed control wire, or corroded connector at the electronics coolant pump
Failed electronics in the pump itself, drawing no current or far too much
Coolant loss from a damaged hose letting the pump run dry (Audi e-tron/Q8 e-tron bulletin)
Faulty output driver in the hybrid or thermal management control module

Symptoms

  • Malfunction indicator lamp or hybrid/drive system warning on
  • Reduced drive power because inverter and charger temperatures rise
  • Charging power reduced or charging interrupted
  • Pump not audible after switch-on when commanded via scan tool

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–700
Time0.5–3 h

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

Parts involved

hybrid electronics coolant pump awiring harnesshybrid control module

Related codes

P0CEAP0CEBP0CECP0CEDP2B2AP2E41

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.