- Engine Light ON (or Service Engine Soon Warning Light)
- A/C Inoperative
- A/C Blows Warm

- A/C evaporator temperature sensor circuit is open or short
- Poor electrical connection at the evaporator temperature sensor circuit
- Faulty Evaporator Temperature sensor

When the ACET signal is detected below the self-test minimum the PCM will triggered the P0535 code.

The PCM sources a low current 5 volts on the A/C Evaporator Temperature (ACET) sensor circuit. As the A/C evaporator air temperature changes, the ACET circuit resistance changes (which changes the voltage the PCM detects).