C1400

C1400-TRANSFER CASE RANGE SELECT SWITCH PERFORMANCE





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the ignition on and no system undervoltage or overvoltage condition present.

- Set Condition:
The Transfer Case Selector Switch is not reporting a valid voltage for any switch position.





Diagnostic Test

1. DTC IS ACTIVE
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, read DTCs in the Final Drive Control Module.
Is the DTC status Active at this time?

Yes

- Go To 2

No

- Go To 8


2. (K504) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT VOLTAGE




Turn the ignition off to the lock position
Disconnect the Transfer Case Selector Switch harness connector.
Ignition on, engine not running.
Measure the voltage of the (K504) Drivetrain 5-volt Supply circuit.
Is the voltage between 4.7 and 5.2 volts?

Yes

- Go To 5

No

- Go To 3

3. (K504) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT OPEN




Turn the ignition off to the lock position
Disconnect the Final Drive Control Module C2 harness connector.
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. Transfer Case Verification Test

No

- Go To 4

4. (K504) DRIVETRAIN 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND




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. Transfer Case Verification Test

No

- Replace the Final Drive Control Module.
- Perform the TRANSFER CASE VERIFICATION TEST-VER 1. Transfer Case Verification Test

5. TRANSFER CASE SELECTOR SWITCH




Ignition on, engine not running.
With the scan tool, read the 4WD Range Switch Voltage with the Transfer Case Selector Switch harness connector disconnected.
The switch voltage should be approximately 0.0 volts.
Turn the ignition off to the lock position
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, 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. Transfer Case Verification Test

No

- Go To 6


6. (K977) MODE SELECT CIRCUIT OPEN




Turn the ignition off to the lock position
Disconnect the Final Drive Control Module C2 connector.
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. Transfer Case Verification Test

No

- Go To 7


7. (K977) MODE SELECT CIRCUIT SHORT TO GROUND




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. Transfer Case Verification Test

No

- Replace the Final Drive Control Module.
- Perform the TRANSFER CASE VERIFICATION TEST-VER 1. Transfer Case Verification Test

8. INTERMITTENT TRANSFER CASE RANGE SELECT SWITCH PERFORMANCE
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. Transfer Case Verification Test

No

- Test complete.