P0071 low

Ambient Air Temperature Sensor Range/Performance

The P0071 code means the vehicle's onboard diagnostic system has detected: Ambient Air Temperature Sensor Range/Performance. This is a low severity code.

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Keep driving?
Yes, but fix soon
DIY difficulty
easy
Estimated cost
$30 - $180 (parts and labor)
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Common Symptoms

  • Check Engine Light on
  • Incorrect ambient temperature reading on dashboard
  • Minor fuel trim adjustments
  • Automatic climate control may behave erratically

Probable Causes (Ranked by Likelihood)

  • Ambient air temperature sensor reading out of range Very High
  • Sensor contaminated with road debris or oil High
  • Poor sensor ground connection Moderate
  • PCM software calibration issue Low

Step-by-Step Diagnostic Procedure

  1. Read ambient air temp PID with scan tool and compare to a known accurate thermometer reading.

  2. Inspect sensor for physical contamination, road debris, or oil film that could insulate the sensing element.

  3. Check sensor ground circuit for resistance. Should be less than 0.5 ohms to ground.

  4. If sensor reads correctly at room temp, monitor the value during a drive to check for intermittent range faults.

Frequently Asked Questions

Is P0071 a serious code?

No, P0071 is a low-severity code. It indicates the ambient air temperature sensor is reading outside the expected range but does not significantly affect driveability.

What causes the ambient air temp sensor to read incorrectly?

The most common cause is a contaminated or failing sensor. Road salt, debris, and age can degrade the sensor element over time.

Will this code affect my emissions test?

Yes, any illuminated Check Engine Light will cause an emissions inspection failure, even for a low-severity code like P0071.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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