GM OBD Trouble Code 71

A/C Evaporator Temperature sensor circuit error (low temp indicated)

The ECM monitors the A/C Evaporator Temperature sensor circuit. If the evaporator temperature is to low the ECM will not allow the A/C compressor to operate.

Fault Code Description

• 71 - A/C Evaporator Temperature sensor circuit error (low temp indicated)

Symptoms

• Poor A/C performance
  

Common Problems

• Faulty A/C Evaporator pressure sensor
• Quick test - On A/C systems with multiple pressure sensors, on a cold engine with the key on and the engine off the scan tool readings for the A/C pressure sensors should all be the same.