P1535

Circuit Description

The A/C high side temperature sensor uses a thermistor to control the signal voltage to the PCM. The PCM applies 5 volts on CKT 732 to the sensor. When the sensor is cold, its resistance is high; therefore, the PCM will see a high signal voltage. As the sensor warms, its resistance becomes less and the signal voltage is pulled low through the ground, CKT 1704. This diagnostic detects a shorted to ground or open A/C high side temperature sensor circuit by setting the DTC if the PCM monitors a signal voltage, temperature, that is too high or low.


Conditions for Setting the DTC

Test Conditions

^ Ambient Air Temperature between 40°F and 210°F

^ Ambient Air Temperature sensor failure not indicated by the HVAC controller.

Failure Condition

A/C high temperature sensor reads less than 12°C (10°F) or more than 210°C (410°F).

Action Taken When the DTC Sets

^ Enable cooling fans to high if A/C clutch engagement is possible.

^ The Malfunction Indicator Lamp (MIL) will not illuminate.

^ No message will be displayed.


Conditions for Clearing the DTC

^ A History DTC will clear after forty consecutive warm-up cycles with no failures of any nonemission related diagnostic test.

^ A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.

^ PCM battery voltage is interrupted.

^ Using a Scan tool.