B108E

B108E-INFRARED TEMPERATURE SENSOR INTERNAL (ATC)

B108E - Infrared Temperature Sensor Internal (ATC):

Theory of Operation
The CMTC receives data from the IR Sensor by means of a dedicated circuit. In turn, the CMTC busses the IR Sensor data to the A/C Heater Control by means of the Controller Area Network (CAN) B Bus. This DTC has a maturing time of 10 seconds and a de-maturing time of 10 seconds. If the DTC's status changes from active to stored it will stay in memory for 100 ignition cycles.

WHEN MONITORED
With the ignition in run.

SET CONDITION
This DTC will set if any of the following occur:
- If the total combined Infrared (IR) Sensor signal on and off time is ≤ 88.79 ms or ≥ 116.01 ms.
- If the IR Sensor duty cycle is ≤ or equal to 9.5%.
- If the IR Sensor duty cycle is in the range of 65.5% up to and including 65.8%.
- If the IR Sensor duty cycle is in the range of 71.8% up to and including 72%.
- If the IR Sensor duty cycle is in the range of 78% up to and including 78.3%.
- If the IR Sensor duty cycle is in the range of 78.3% up to and including 84.3% (this indicates and IR EEPROM fatal error).
- If the IR Sensor duty cycle is in the range of 84.3% up to and including 100%.

POSSIBLE CAUSES
- IR sensor circuit(s)
- IR sensor
- Compass mini-trip computer (CMTC)

NOTE: DTC B108E must be active for the results of this test to be valid. Do not perform this test if DTC B108E is stored. Refer to HVAC System Test (ATC) for stored DTC test procedures. HVAC System Test (ATC)

Diagnostic Test

1. CHECK THE CMTC FOR DTCs
Turn the ignition on.
With the scan tool, check the Compass Temperature Module (EOM) for DTCs.

Q: Are any DTCs present?

YES: Refer to Overhead Console for the related symptom(s).
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Replace the IR Sensor.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test