P1533

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The A/C low side temperature sensor uses a thermister to control the signal voltage to the PCM. The PCM applies 5 volts on CKT 731 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, 01cr 470. This diagnostic detects a shorted to ground or open A/C low side temperature sensor circuit by setting the DTC if the PCM monitors a signal voltage, temperature, that is too high or low.

CONDITIONS FOR RUNNING THE DTC

^ Ambient Air Temperature between 4°C (39°F) and 99°C (210°F).

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

CONDITIONS FOR SETTING THE DTC

A/C low side temperature sensor reads less than -37°C (-35°F) or more than 99°C (210°F).

ACTION TAKEN WHEN THE DTC SETS

^ Disable the A/C compressor clutch.

^ 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 non-emission 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.

DIAGNOSTIC AIDS

With the vehicle engine not running and at ambient temperature the A/C temperature sensor should also be near ambient temperature. If the A/C temperature sensor is not near ambient temperature check for a sensor or circuit with resistance that is too high or too low. A sensor temperature reading that is too high would indicate a shorted or low resistance sensor or circuit. A sensor temperature reading that is too low would indicate an open or high resistance sensor or circuit.