Lotus Evora - A;C Evaporator Temperature Sensor

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Lotus Service Notes Section EMR
A/C Evaporator temperature sensor
P0537 A/C Evaporator temperature sensor circuit low
P0538 A/C Evaporator temperature sensor circuit high
Description
The A/C system incorporates an evaporator temperature sensor for system control. This is a thermistor device
that changes resistance with temperature. As the evaporator temperature decreases the thermistor resistance
value increases, and conversely as the evaporator temperature increases so the thermistor resistance value
decreases.
Sensor connections
Sensor Connector Description ECU Pin ECU Connector
1 Sensor signal A3 48 Way (Right)
1 Sensor ground K3 48 Way (Right)
Monitor:
• Continuous
Enable Criteria:
• VehicleRunning
Disable Criteria:
• None
Malfunction Criteria:
• P0537–Signalvoltage<0.049Vfor1.5seconds
• P0538–Signalvoltage>4.399Vfor1.5seconds
Potential failure modes:
• Thermistorwiringopencircuitorshorted
• Thermistorfault
Diagnostic Mask:
• Theservicelightwillbeilluminatedfor30secondsafterenginestartifthefaulthasbeenpresentforthe
previous two trips.
2009/02