Powertrain, generic · Hybrid propulsion

P0A03 Motor Electronics Coolant Temperature Sensor A Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

The sensor signal voltage is above its valid window, which for an NTC thermistor reads as an impossibly cold coolant temperature. Typical reasons are an open circuit in the sensor or its wiring, or a short to a voltage source. GM monitors this on the 2013 Two-Mode hybrid Tahoe, Yukon, Escalade, Silverado and Sierra with a limit of -59.1 °C, counted as 30 failures in 50 samples at 100 ms intervals once propulsion has been active for over 10 s and the intake air sensor codes P0112 and P0113 are clear; Type B, MIL after two trips. P0A02 covers the reverse case. Because the system cannot see real heat any more, it often reduces electric power as a precaution.

Likely causes

Connector unplugged, loose or with a pushed-back terminal
Broken signal or ground wire of the sensor
Thermistor element open internally
Signal wire shorted to a voltage supply

Symptoms

  • Check engine or hybrid warning light
  • Electronics temperature shown far below ambient
  • Reduced electric drive power as a safeguard

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–900
Time0.5–3 h

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

Parts involved

motor electronics coolant temperature sensorhybrid inverterwiring harness

Related codes

P0A00P0A01P0A02P0A04P2BD8

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