P0072: Ambient Air Temperature Sensor Circuit A Low. Meaning, possible symptoms and checks before repair.
Meaning, symptoms, causes and checks
The controller detects an excessively low electrical input in ambient air temperature sensor A. Low refers to the electrical input, not necessarily cold weather. Sensor location and the module receiving its signal vary. The displayed temperature may also have a normal update delay.
Affected system: Powertrain
Symptoms
- Implausible or unavailable outside-temperature display.
- Engine warning light; climate control or other functions may use a substitute value.
Possible causes
- Loose or corroded connector, or damaged wiring.
- Failed sensor or supply/return circuit problem, depending on the circuit design.
What to check
- Read codes in the involved modules and identify sensor A in the vehicle information, including any mirror-mounted installation.
- Compare the reading with an independent thermometer after stabilization, observing the manufacturer’s display-update conditions.
- Inspect connector seating, terminal retention and wiring exposed to water or impact; consider recent body repairs.
- Check for a possible short to ground and observe the input with the sensor disconnected only as directed by the diagram.
- After repair, clear codes and recheck outside temperature under the original recorded conditions, following the manufacturer’s procedure.
Also written as: P0072-00, P007200, PO072 (some scan tools add the fault-type byte, e.g. -00).