P0074
Ambient Air Temperature Sensor Circuit A Intermittent/Erratic
Intermittent dropouts or noise on the ambient air temperature sensor A signal — typically a loose connector or chafed wiring.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: easy
Common causes
Ordered by how often each turns out to be the cause.
- Connector loose or corrodedCommon
- Connector with intermittent contact under vibrationLess likely
- Harness routed against vibrating componentLess likely
Parts involved
- Ambient Air Temp Sensor
- Sensor Wiring
P0074 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.