P0074
Ambient Air Temperature Sensor Circuit A Intermittent/Erratic
Fuel & air metering
Generic OBD-II
Low
What it means
P0074 means the signal from the ambient (outside) air temperature sensor is cutting out or jumping around rather than reading steadily. It's usually a loose connector or chafed wire. This sensor feeds the climate system and minor fuel trims, so the engine keeps running normally even though the code is set.
Low
Can I keep driving? Safe to keep driving — this mainly affects the outside-temperature reading used by the climate system and minor fuel adjustments, not how the engine runs.
Common symptoms
What you'll notice
- Check-engine light on
- Erratic or jumping outside-temperature reading
- Climate/AC system behaving oddly or displaying wrong temperature
- Slightly reduced fuel economy in some vehicles
Common causes
Most likely first
- Loose or corroded connector at the ambient air temperature sensorLikely
- Damaged, chafed, or intermittently shorting wiringCommon
- Failed ambient air temperature sensorCommon
- Faulty engine control module (ECM) — rareLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and view the live ambient temperature signal for dropouts.
- Inspect the sensor connector and wiring; do a wiggle test to catch the intermittent fault.
- Clean or repair corroded terminals and secure loose connections.
- Compare the sensor's resistance to a temperature chart and replace it if out of spec.
- If wiring and sensor are good, consider the ECM last. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0074?+
Yes. This sensor reads outside air temperature and has little effect on how the engine runs; it mostly affects the climate system and gauge.
Can I just clear P0074?+
You can, but because the fault is intermittent it will return until the loose connection, wiring, or sensor is repaired.
Related codes
Often seen with P0074
Read & clear P0074 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX