Ambient Temperature Sensor Fault Codes

The outside temperature function is supported by the ambient temperature sensor (ATS), a signal and ground circuit hardwired to the NGC or HVAC module, and the CMTC display.

If the CMTC display indicates 54°C (130°F) or the ATS sense circuit is shorted to ground, the temp display will be 54°C (130°F) to indicate a SHORT circuit condition.

If the CMTC display indicates -40°C (-40°F) or the ATS sense circuits is open, the temp display will be -40°C (-40°F) to indicate an OPEN circuit condition.

If there is an OPEN or SHORT circuit condition, it must be repaired before the CMTC VFD can be tested.

The ATS is supported by the NGC or HVAC module. Ambient Temperature Sensor DTCs will be recorded in the NGC or HVAC module. The ATS can be diagnosed using the following Sensor Test. Test the ATS circuits using the diagnostics in DIAGNOSTIC INFORMATION & PROCEDURES  . If the CMTC passes the self test, and the ATS, the circuits, and PCI bus communications are confirmed to be OK, but the CMTC temperature display is inoperative or incorrect, replace NGC or HVAC module.