P0A03Motor Electronics Coolant Temperature Sensor A Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- 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.
- What you may notice
- Check engine or hybrid warning light
- Electronics temperature shown far below ambient
- Reduced electric drive power as a safeguard
- Likely causes
- LikelyConnector unplugged, loose or with a pushed-back terminal
- PossibleBroken signal or ground wire of the sensor
- PossibleThermistor element open internally
- RareSignal wire shorted to a voltage supply
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.