Electrical and sensors

P0070 — Ambient Air Temperature Sensor Circuit Malfunction

Severity: low Safe to drive

What P0070 means

The control module monitors the signal from the ambient (outside) air temperature sensor. The sensor is a thermistor whose resistance changes with temperature, which lets the module calculate the outside temperature. P0070 sets when the signal is out of range, such as an open circuit, a short to ground or voltage, or an implausible reading.

Symptoms

  • Check engine light on
  • Outside temperature display missing or clearly wrong
  • Climate control behaving oddly
  • Slightly unstable idle after a cold start (uncommon)
  • Slightly higher fuel consumption (uncommon)

Possible causes

  1. Failed ambient air temperature sensor
  2. Open or shorted wiring in the sensor circuit
  3. Corroded or loose connector
  4. Water intrusion in the connector or harness
  5. Harness damage from a front bumper repair or collision
  6. Control module input circuit fault (rare)

How to diagnose

  1. Scan for codes and view live data; compare the reported ambient temperature with the real one.
  2. Inspect the sensor (usually behind the bumper or grille) and connector for damage, moisture and corrosion.
  3. Unplug the connector and confirm the reading shifts to the extreme value, as expected for an open circuit.
  4. Measure sensor resistance with a multimeter and compare it to the spec table for your vehicle.
  5. Check for the reference voltage (typically about 5 V) and a good ground at the connector.
  6. Test the wiring to the module for opens and shorts to ground or voltage.
  7. If the sensor and wiring are good, test the module that reads the signal.

Common fixes

  • Replace the ambient air temperature sensor
  • Repair or replace damaged wiring
  • Clean and secure the connector, and protect the contacts
  • Repair or replace the control module (very rare)

P0070 on different brands

Ford · manuals
Ford documents a P0070:16 interpretation meaning the sensor circuit voltage is below the threshold (circuit low); it identifies the monitor condition detected, not a confirmed failed part.

Questions and answers

Can I drive with code P0070?

Yes, it normally does not affect safety or the engine. Still, fix it soon to restore correct climate control and temperature readings.

Why is my outside temperature not showing with P0070?

The module is not getting a valid signal because of an open, a short or a bad sensor. Start by inspecting the sensor and its connector.

How do I clear P0070?

Repair the cause first, then clear the code with a scan tool. If the fault remains, the code will return.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.