A/C Refrigerant Temperature Sensor/Circuit Malfunction
Your car's A/C refrigerant temperature sensor isn't sending the right signal to the engine computer, like a broken thermometer that can't tell if your coolant is hot or cold. The ECU can't properly control the A/C compressor because it doesn't know the refrigerant temperature.
The ECU monitors voltage signals from the refrigerant temperature sensor to determine if the A/C system is operating safely. The sensor resistance changes with refrigerant temperature, and the ECU uses this data to prevent compressor damage from overheating or pressure issues. When voltage readings fall outside expected parameters, a fault is triggered.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Sensor Voltage | 0.5–4.5 volts (varies with temp) | Out-of-range voltage or no signal |
| Refrigerant Temp | 32–140°F (0–60°C) | Extreme readings or sensor disconnected |
Code P1471 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P1471 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.