Discharge Temperature Sensor Check
refrigeration
Description
The Ambient Air Temperature Sensor is out of range, and the unit uses 122°F (50°C) for calculations in Engine and Shore Power Operation.
Activation Conditions
Ambient Air Temperature Sensor (AAT) is not within range of -53 to +158°F (- 47° to +70° C).
Unit Behavior
Engine and Shore Power Operation: A value of 122°F (50°C) will be used for any calculations.
Reset Conditions
Auto reset when sensor is in range or alarm may be manually reset using the AI or by turning the unit off, then back on again.
Corrective Actions
1. Check Sensor a. Inspect sensor, harness and connector for damage, moisture, or corrosion. b. Check sensor resistance. 10,000 Ohms @ 77°F (25°C). Refer to Table 8–3 for chart of resistances for different sensors. 2. Check Sensor Wiring a. Inspect connector pins & terminals at J8. Verify there is no physical damage to harness, and no damage, moisture, or corrosion in the connector. b. Set unit to Run Mode HVAC OFF. Refer to Note Disconnect harness from CCM. Check for 3.0 ± 0.1 VDC between J8-1 and J8-2 connector pins. Voltage should be 3.0 ± 0.1 VDC volts at harness plug between pins. This verifies microprocessor.