T-CASE SWITCH LOW (BCM)
For a complete wiring diagram Refer to Section 8W.
- When Monitored:
With the ignition on.
- Set Condition:
The Body Control Module (BCM) will set this DTC if voltage drops below 0.155 volts for more than 5 seconds on the (K77) Transfer Case Position Sensor Input circuit.
| Possible Causes |
| (K77) TRANSFER CASE POSITION SENSOR INPUT CIRCUIT SHORTED TO GROUND |
| (K77) TRANSFER CASE POSITION SENSOR INPUT CIRCUIT SHORTED TO THE (K300) SENSOR GROUND CIRCUIT |
| TRANSFER CASE POSITION SENSOR |
| BCM |
Diagnostic Test
1. CHECK THE TRANSFER CASE POSITION SENSOR INPUT VOLTAGETurn the ignition on.
With the scan tool, read the Transfer Case Position Sensor Input voltage.
Is the voltage below 0.5 volts?
Yes
- Go To 2
No
- Go To 5
2. CHECK THE TRANSFER CASE POSITION SENSOR INPUT VOLTAGE WITH THE SENSOR DISCONNECTED
Turn the ignition off.
Disconnect the Transfer Case Position Sensor harness connector.
Turn the ignition on.
With the scan tool, read the Transfer Case Position Sensor voltage.
Is the voltage above 4.6 volts?
Yes
- Replace the Transfer Case Position Sensor in accordance with the Service Information.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To 3
3. CHECK THE (K77) TRANSFER CASE POSITION SENSOR INPUT CIRCUIT FOR A SHORT TO GROUND
Turn the ignition off.
Disconnect the BCM C2 harness connector.
Measure the resistance between ground and the (K77) Transfer Case Position Sensor Input circuit at the Transfer Case Position Sensor harness connector.
Is the resistance below 10k ohms?
Yes
- Repair the (K77) Transfer Case Position Sensor Input circuit for a short to ground.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To 4
4. CHECK THE (K77) TRANSFER CASE POSITION SENSOR INPUT CIRCUIT FOR A SHORT TO THE (K300) SENSOR GROUND CIRCUIT
Measure the resistance between the (K77) Transfer Case Position Sensor Input circuit and the (K300) Sensor Ground circuit at the Transfer Case Position Sensor harness connector.
Is the resistance below 10k ohms?
Yes
- Repair the (K77) Transfer Case Position Sensor Input circuit for a short to the (K300) Sensor Ground circuit.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Replace and program the BCM in accordance with the Service Information.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
5. TEST FOR INTERMITTENT CONDITION
NOTE: The condition that set this DTC is not present at this time. The following may help in identifying the cause of the intermittent condition.
Check the Technical Service Bulletins (TSBs) for related concerns.
Turn the ignition on.
Using the scan tool, erase BCM DTCs.
Turn the ignition off, wait 10 seconds, then turn the ignition on.
Monitor the scan tool for DTCs while wiggling the related wiring harness.
Turn the ignition off.
Using the wiring diagram/schematic as a guide, inspect the related wiring and connectors for chaffed, pierced, pinched, and partially broken wires, and for broken, bent, pushed out, corroded, and contaminated terminals. Repair as necessary.
Perform a voltage drop test on the related circuits between the component and the BCM.
If numerous DTCs were set, use the wiring diagram/schematic to check for common ground and supply circuits.
Were any problems found?
Yes
- Repair as necessary.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Test Complete.