C1401
C1401-TRANSFER CASE RANGE SELECT SWITCH CIRCUIT LOWWiring Diagram:
- When Monitored:
With the ignition on and no system undervoltage or overvoltage or supply voltage low conditions present.
- Set Condition:
The 4WD Range Switch Voltage is below a specified value for a calibrated amount of time.
Possible Causes
INTERMITTENT TRANSFER CASE RANGE SELECT SWITCH CIRCUIT LOW
(K504) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND
(K504) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT SHORTED OPEN
(K977) MODE SELECT CIRCUIT SHORTED TO GROUND (K977)
MODE SELECT CIRCUIT SHORT OPEN
TRANSFER CASE SELECTOR SWITCH
FINAL DRIVE CONTROL MODULE
Diagnostic Test
1. 4WD RANGE SWITCH VOLTAGE LESS THAN 0.2 VOLTS
Ignition on, engine not running.
NOTE: Repair any system undervoltage or overvoltage DTCs that are set in this module before proceeding.
With the scan tool under Data Display, read the 4WD Range Switch Voltage.
Is the voltage less than 0.2 volts?
Yes >> Go To 2
No >> Go To 9
2. TRANSFER CASE SELECTOR SWITCH
Turn the ignition off. Disconnect the Transfer Case Selector Switch harness connector. Connect a jumper wire between the (K504) Drivetrain 5 Volt Supply circuit and the (K977) Mode Select circuit in the Transfer Case Selector Switch harness connector. Ignition on, engine not running.
With the scan tool under Data Display, read the 4WD Range Switch Voltage.
The switch voltage should be approximately 5.0 volts.
Does the voltage display as described?
Yes >> Replace the Transfer Case Selector Switch. Perform the TRANSFER CASE VERIFICATION TEST-VER 1. Verification Tests
No >> Go To 3
3. (K504) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT VOLTAGE
Turn the ignition on. Measure the voltage between ground and the (K504) Drivetrain 5 Volt Supply circuit. The voltage should be approximately 5.0 volts.
Does the voltage display as described?
Yes >> Go To 6
No >> Go To 4
4. (K504) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND
Turn the ignition off. Disconnect the Final Drive Control Module C2 harness connector. Measure the resistance between ground and the (K504) Drivetrain 5 Volt Supply circuit.
Is the resistance less than 5.0 ohms?
Yes >> Repair the (K504) Drivetrain 5 Volt Supply circuit for a short to ground. Perform the TRANSFER CASE VERIFICATION TEST-VER 1. Verification Tests
No >> Go To 5
5. (K504) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT OPEN
Measure the resistance of the (K504) Drivetrain 5 Volt Supply circuit between the Transfer Case Selector Switch harness connector and the Final Drive Control Module C2 harness connector.
Is the resistance greater than 5.0 ohms?
Yes >> Repair the (K504) Drivetrain 5 Volt Supply circuit for an open. Perform the TRANSFER CASE VERIFICATION TEST-VER 1.Verification Tests
No >> Go To 8
6. (K977) MODE SELECT CIRCUIT SHORT TO GROUND
Turn the ignition off.
Disconnect the Final Drive Control Module C2 harness connector.
Measure the resistance between ground and the (K977) Mode Select circuit.
Is the resistance less than 5.0 ohms?
Yes >> Repair the (K977) Mode Select circuit for a short to ground. Perform the TRANSFER CASE VERIFICATION TEST-VER 1. Verification Tests
No >> Go To 7
7. (K977) MODE SELECT CIRCUIT OPEN
Measure the resistance of the (K977) Mode Select circuit between the Transfer Case Selector Switch harness connector and the Final Drive Control Module C2 harness connector.
Is the resistance above 5.0 ohms?
Yes >> Repair the (K977) Mode Select circuit for an open. Perform the TRANSFER CASE VERIFICATION TEST-VER 1.Verification Tests
No >> Go To 8
8. FINAL DRIVE CONTROL MODULE
View repair.
Repair - Replace the Final Drive Control Module. Perform the TRANSFER CASE VERIFICATION TEST-VER 1.Verification Tests
9. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. While monitoring the scan tool data relative to this circuit, wiggle test the wiring and connectors. Look for the data to change or for the DTC to reset during the wiggle test. While monitoring the scan tool data relative to this circuit, move the selector switch to each position several times. Look for the data to change other than as expected or for the DTC to reset.
Were any problems found?
Yes >> Repair as necessary. Perform the TRANSFER CASE VERIFICATION TEST-VER 1. Verification Tests
No >> Test complete.