P0A03 code meaning
Motor Electronics Coolant Temperature Sensor A Circuit High
Powertrain system Generic code P0Axx codes Check engine light
What P0A03 means
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.
P0A03 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P0A03
- Check engine or hybrid warning light
- Electronics temperature shown far below ambient
- Reduced electric drive power as a safeguard
Common causes of P0A03
- Most likelyConnector unplugged, loose or with a pushed-back terminal
- PossibleBroken signal or ground wire of the sensor
- PossibleThermistor element open internally
- Less likelySignal wire shorted to a voltage supply
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Motor electronics coolant temperature sensorHybrid inverterWiring harness
What each part of P0A03 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| A | Area: hybrid propulsion. |
| 03 | The exact fault in that area. |
What to do next
- Note P0A03 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0A03
What does P0A03 mean?
P0A03 means "Motor Electronics Coolant Temperature Sensor A Circuit High". The sensor signal voltage is above its valid window, which for an NTC thermistor reads as an impossibly cold coolant temperature. It is a generic code, so it means the same on every make.
Is it safe to drive with P0A03?
Drive gently and only to a workshop. With P0A03 the car can go into limp mode (reduced power) to protect itself.
Will P0A03 fail an emissions test?
Yes, it can. P0A03 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0A03 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P0A03 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.