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

1.CHECK THE TRANSFER CASE POSITION SENSOR INPUT VOLTAGE

Is the voltage below 0.5 volts?

Yes

2.CHECK THE TRANSFER CASE POSITION SENSOR INPUT VOLTAGE WITH THE SENSOR DISCONNECTED

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).

3.CHECK THE (K77) TRANSFER CASE POSITION SENSOR INPUT CIRCUIT FOR A SHORT TO GROUND

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).

4.CHECK THE (K77) TRANSFER CASE POSITION SENSOR INPUT CIRCUIT FOR A SHORT TO THE (K300) SENSOR GROUND CIRCUIT

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).

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.

Were any problems found?

Yes