The MAT sensor is supplied with a 5 V reference voltage at Pin 2 from ECM Pin X2–14. The sensor is grounded at Pin 1 through the signal ground at ECM Pin X1–6. As the air temperature increases or decreases, the sensor changes resistance and provides the air temperature signal voltage at the ECM. The signal voltage is monitored by the ECM to
determine the temperature of the air.
Fault Detection / Management
The ECM continuously monitors the signal of the MAT sensor to determine if the signal is within an expected range. If the ECM detects the signal voltage is greater or less than expected, the ECM will set a DTC.
MAT Diagnostic Trouble Codes (DTCs)
DTCs are read using the EST or by counting the flashes from the amber and red ENGINE lamp.
DTC 161
MAT signal out-of-range low
• DTC 161 is set by the ECM when the signal voltage is less than 0.098 V for more than 0.35 second.
• DTC 161 can be set due to a short to ground in the signal circuit or a failed MAT sensor.
• When DTC 161 is active the amber ENGINE lamp is illuminated.
DTC 162
MAT signal out-of-range high
• DTC 162 is set by ECM when the signal voltage is greater than 4.58 V for more than 0.35 second.
• DTC 162 can be set due to an open signal or ground circuit , short to a voltage source, or a failed MAT sensor.
• When DTC 162 is active the amber ENGINE lamp is illuminated.
Tools
• EST with MasterDiagnostics® software
• EZ-Tech® interface cable
• Digital Multimeter (DMM)
• 3-Banana Plug Harness
• 500 Ohm Resistor Harness
• Breakout Box
• Breakout Harness
• Terminal Test Adapter Kit
