Ambient Air Temperature Sensor Circuit A Range/Performance
What it means
P0071 means the ambient (outside) air temperature sensor is reporting a value the ECM judges to be implausible or slow to change. This sensor mainly drives the outside-temperature display and some climate-control and minor fuel calculations, so its real-world impact is small — the engine runs normally and the car will still start. The usual cause is a failing sensor, poor wiring, or a sensor location picking up stray heat.
Can I keep driving? Yes — this sensor mainly feeds the temperature display and minor calculations; the car drives normally, though the outside-temp reading may be wrong.
Common symptoms
What you'll notice
- Check-engine light on
- Inaccurate outside-temperature reading on the dash
- Climate control or defrost behaving oddly
- Minor effect on fuel trim on some vehicles
Common causes
Most likely first
- Failed or drifting ambient air temperature sensor (most common)Likely
- Sensor exposed to engine or road heat giving false readingsCommon
- Damaged wiring or corroded connector at the sensorCommon
- Failed ECM or HVAC module (rare)Less often
How to diagnose & fix
Work through it in order
- Compare the sensor's reported temperature to actual outside temperature with a scan tool.
- Inspect the sensor connector and wiring for damage or corrosion.
- Check the sensor's resistance against a temperature-resistance chart.
- Replace the ambient air temperature sensor if out of spec.
- Clear the code and confirm the reading is realistic.
FAQ
Quick answers
Is it safe to drive with P0071?+
Can I just clear P0071?+
Related codes
Often seen with P0071
Read & clear P0071 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.