Fault Code 13

Fault Code 13

Evaporator Temperature Sensor
- Sensor, harness or Air Conditioning Control Module (A/CCM) open circuit.
- Sensor, harness or A/CCM short circuit to ground.

This sensor monitors the temperature of the evaporator matrix, the output is used to trigger the compressor circuit via the A/CCM pin 34 (12-way connector).

If the signal on pin 34 (12-way connector) remains at less than 1 volt, suspect either a short circuit to ground on the signal wire or an open circuit on the 5 volt supply to the sensor If the signal on pin 34 rises to approximately 5 volts then suspect an open circuit on the sensor ground.

Check the voltage, against the graph below (Fig 1), measured between pin 34 (12-way connector) and pin 19 (22-way connector) A/CCM.

Characteristics Of Evaporator Temperature Sensor, Fig.1:

If the voltage is within the set limits, the system is operating correctly.

A resistance check can be carried out on the sensor and should conform with the figures below, measured between pin 34 (12-way connector) and pin 19 (22-way connector) A/CCM.

0 °C 4.6 - 5.1 K Ohm
15 °C 2.1 - 2.6 K Ohm

If the resistance is outside the set limits, renew the sensor.


NOTE: The resistance should continue to decrease as the temperature increases and vice versa.


Inspect sensor harness for open circuit or short circuit to ground. repair as necessary.

If the voltage is outside the set limits, renew the A/CCM.