Faulty ambient air temperature sensor; Damaged or corroded wiring or connector at the sensor; Open or short circuit in the signal or ground circuit; Ambient temperature sensor signal circuit shorted to voltage or ground; Failed powertrain control module (PCM) or body control module (BCM) in rare cases; Sensor exposed to extreme heat or physical damage from road debris

DTC codes / P00xx · Fuel and air metering and auxiliary emission controls / P0070

P0070Ambient Air Temperature Sensor Circuit

Q: What does code P0070 mean?

Ambient Air Temperature Sensor Circuit. P0070 indicates that the powertrain control module (PCM) has detected an abnormal condition in the ambient air temperature sensor circuit, which measures the outside air temperature. The computer monitors the sensor's signal voltage and sets this code when the reading falls outside the expected range or the circuit fails a rationality check.

P0070 indicates that the powertrain control module (PCM) has detected an abnormal condition in the ambient air temperature sensor circuit, which measures the outside air temperature. The computer monitors the sensor's signal voltage and sets this code when the reading falls outside the expected range or the circuit fails a rationality check.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaFuel and air metering and auxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Outside temperature display on the dashboard shows dashes or an incorrect value
Climate control system may not regulate cabin temperature as expected
Remote start feature may be disabled on vehicles that use ambient temperature for logic
Engine cooling fan may run continuously or not at all if the PCM substitutes a default value

Common causes, most likely first

Faulty ambient air temperature sensor
Damaged or corroded wiring or connector at the sensor
Open or short circuit in the signal or ground circuit
Ambient temperature sensor signal circuit shorted to voltage or ground
Failed powertrain control module (PCM) or body control module (BCM) in rare cases
Sensor exposed to extreme heat or physical damage from road debris

How to diagnose and fix it

Use an OBD-II scanner to confirm P0070 and check for related codes in other modules
Inspect the ambient temperature sensor and its connector for physical damage or corrosion
Measure sensor resistance and compare to the manufacturer's temperature-resistance chart
Check for continuity and voltage on the signal and ground circuits between the sensor and the PCM
Repair or replace damaged wiring or connector terminals as needed
Replace the ambient air temperature sensor if it fails electrical testing
Clear codes and verify the temperature reading on a scan tool matches actual ambient conditions

What the ambient sensor really controls

Many vehicles use the ambient air temperature sensor for climate control and remote start logic, so a failure can cause comfort or convenience issues beyond the check engine light.
A common misdiagnosis is replacing the sensor when the real problem is a corroded connector or a chafed wire in the harness near the front bumper.
The PCM may substitute a default ambient temperature value when the sensor fails, which can mask driveability symptoms but still trigger the code.
On some models, the ambient temperature sensor is shared with the outside temperature display, and a faulty sensor can cause the display to show erratic readings.
Always check for technical service bulletins (TSBs) for the specific vehicle, as some manufacturers have known issues with sensor placement or wiring routing.

Can I keep driving with P0070?

The vehicle is safe to drive with P0070 because the fault does not affect engine operation or safety systems. However, avoid relying on the outside temperature display or automatic climate control until the issue is repaired.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.