P0070: Ambient Air Temperature Sensor Circuit A

What it means

The control module detects an electrical fault in the ambient air temperature sensor circuit.

At a glance

• Usually lights the check-engine light

How it works

Ambient air temperature sensor A measures outside air temperature for the control module and may also supply the dashboard display or climate system. P0070 sets when the module detects an electrical fault in that sensor's circuit, such as an open wire, loose connector, or failed sensor element.

Common causes

Most likely first.

1. Sensor element failed
2. Wiring open or connector loose

Symptoms

• Check-engine light on
• Outside-temperature display may be incorrect
• Automatic climate control may behave unexpectedly

How to diagnose it

1. Check the stored code and live ambient temperature reading, noting whether it is fixed, missing, or clearly implausible.
2. Inspect sensor A's location and connector for looseness, corrosion, water intrusion, or physical damage.
3. Follow the sensor A wiring back toward the harness and look for a break, chafe, or disconnected plug.
4. Check circuit continuity and the sensor signal using the manufacturer's wiring information and specifications.
5. If wiring and connections pass, test or replace ambient temperature sensor A based on the manufacturer's checks.

Common fixes

• Reconnect a loose ambient temperature sensor A plug.
• Clean corroded terminals or repair a damaged connector.
• Repair an open or damaged section of sensor wiring.
• Replace ambient temperature sensor A if it fails testing.

Can I keep driving?

This fault usually does not affect basic engine operation, so normal driving is generally possible. Expect the outside temperature display or automatic climate control to behave incorrectly until the circuit is repaired.