Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Test
- READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN
- With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
- With the scan tool, run a Vehicle Scan Report or record the Environmental Data.
- With the scan tool, erase DTCs.
- Turn the ignition off for at least 10.0 seconds.
- Turn the ignition on.
- Using the recorded Environmental Data and the When Monitored Conditions, operate the vehicle in the conditions that set the DTC.
- With the scan tool, read DTCs.
Did the DTC return?
Yes
- Go To Next Step
No
- Perform the TESTING FOR AN INTERMITTENT CONDITION procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
- ISOLATE AND CHECK THE (T310) POSITION SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
- The ignition must be off when checking the continuity of a circuit.
- Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and the component harness connectors containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit. Check the disconnected connectors and related harnesses for damage, corrosion, and loose fitting terminals.
- Before testing a circuit, measure the resistance between the two leads of the Digital Volt-Ohm Meter (DVOM). Note: Resistance in the meter leads can cause an error in the test results.
- Connect one lead of the DVOM to the circuit being tested at the component harness connector.
- Connect the other lead to the circuit being tested at the ECU harness connector and measure the resistance of the circuit.NOTE:
When back-probing a circuit at a harness connector, always use an appropriate back probing tool to prevent damage to the connector terminals.
Is the resistance below 3.0 Ohms?
Yes
- Go To Next Step
No
- Repair the circuit for an open or high resistance.
- Perform the DTCM VERIFICATION TEST. Refer to DTCM VERIFICATION TEST .
- ISOLATE AND CHECK THE (T304) SENSOR RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE
- The ignition must be off when checking the continuity of a circuit.
- Isolate the circuit by disconnecting the ECU and the component harness connectors containing the circuit being tested. Note: Use the wiring diagram as a guide to follow the path of the circuit. Check the disconnected connectors and related harnesses for damage, corrosion, and loose fitting terminals.
- Before testing a circuit, measure the resistance between the two leads of the DVOM. Note: Resistance in the meter leads can cause an error in the test results.
- Connect one lead of the DVOM to the circuit being tested at the component harness connector.
- Connect the other lead to the circuit being tested at the ECU harness connector and measure the resistance of the circuit.NOTE:
When back-probing a circuit at a harness connector, always use an appropriate back probing tool to prevent damage to the connector terminals.
Is the resistance below 3.0 Ohms?
Yes
- Go To Next Step
No
- Repair the circuit for an open or high resistance.
- Perform the DTCM VERIFICATION TEST. Refer to DTCM VERIFICATION TEST .
- REPLACE THE TRANSFER CASE RANGE POSITION SENSOR AND CHECK FOR THE DTC TO RETURN
- Replace the Transfer Case Range Position Sensor in accordance with the Service Information. .
- Connect the component and ECU harness connectors.
- Turn the ignition on.
- With the scan tool, erase DTCs.
- Using the Environmental Data or When Monitored information above, operate the vehicle within the conditions that set the DTC.
- With the scan tool, read DTCs.
Did the DTC return?
Yes
- Go To Next Step
No
- Replacing the Transfer Case Range Position Sensor corrected the condition.
- Perform the DTCM VERIFICATION TEST. Refer to DTCM VERIFICATION TEST .
- CHECK RELATED HARNESS CONNECTIONS
- Disconnect all Drivetrain Control Module (DTCM) harness connectors.
- Disconnect all related in-line harness connections (if equipped).
- Disconnect the related component harness connectors.
- Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
- Proper connector installation.
- Damaged connector locks.
- Corrosion.
- Other signs of water intrusion.
- Weather seal damage (if equipped).
- Bent terminals.
- Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
- Terminals that have been pushed back into the connector cavity.
- Perform a terminal drag test on each connector terminal to verify proper terminal tension.
Repair any conditions that are found.
- Reconnect all DTCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
- Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
- Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
- With the scan tool, erase DTCs.
- Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
- With the scan tool, read DTCM DTCs.
Did the DTC return?
Yes
- Replace the DTCM in accordance with the Service information. Refer to MODULE, DRIVETRAIN CONTROL (DTCM), REMOVAL AND INSTALLATION .
- Perform the DTCM VERIFICATION TEST. Refer to DTCM VERIFICATION TEST .
No
- The wiring or poor connection problem has been repaired.
- Perform the DTCM VERIFICATION TEST. Refer to DTCM VERIFICATION TEST .
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.