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Evaporator Low Ambient Protection (L61/L66): Notes

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The refrigerant temperature at the temperature sensor in the thermal expansion valve (TXV) controls cycling of the compressor clutch to prevent freezing of the evaporator core. The compressor is disabled when the temperature goes below 3°C (37°F) and vehicle speed is greater than 8 km/h (5 mph). The compressor is enabled when the temperature exceeds 4°C (40°F). The minimum cycling time off is 4 seconds. For purposes of converting a voltage to a temperature value in the diagnosis of the temperature sensor located within the TXV at the inlet outlet of the Evaporator the following conversion chart has been inputted.

Air Temperature Description and Operation

TEMP (°C / °F) MIN / MAX BCM Voltage
-2 / 28 2.80 / 2.90
-1 / 30 2.73 / 2.83
0 / 32 2.66 / 2.76
1 / 34 2.59 / 2.69
2 / 36 2.52 / 2.62
3 / 38 2.45 / 2.55
4 / 40 2.38 / 2.48
6 / 42 2.31 / 2.41
7 / 44 2.25 / 2.35
24 / 75 1.34 / 1.37
SET POINT
-40 / -40 OPEN (4.85)
81 / 178 GROUND (0.122)