P0A04Motor Electronics Coolant Temperature Sensor A Circuit Intermittent
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- The temperature signal from the drive electronics coolant loop jumps or drops out for short moments, then returns to normal. Coolant temperature changes slowly, so a sudden step that the physics cannot explain points to a loose contact rather than a real temperature change. No manufacturer documents P0A04 publicly. GM's Two-Mode hybrids check the same sensor only for steady faults (P0A01 to P0A03), and a Nissan patent shows how an inverter coolant sensor is compared with the power element temperature to catch implausible readings. CARB requires such inverter cooling inputs to be monitored. The driver may see a warning light that comes and goes, with occasional power reduction.
- What you may notice
- Warning light that appears and disappears
- Short, unexplained drops in electric drive power
- Stored code with no steady fault on re-test
- Likely causes
- LikelyLoose or fretting terminal at the sensor or module connector
- PossiblePartly broken wire that opens under vibration or heat
- RareSensor with an internal intermittent contact
- 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 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.