Special Tools
EL-49742 - Battery Voltage B+ and Ground Source Harness
Circuit/System Verification
1. Verify that the TREC fuse, and the Miscellaneous IGN fuse, underhood fuse block, are not open.
锟斤拷If the TREC fuse is open, test the battery positive voltage circuit, TCCM harness X3 pin C, for a short to ground.
锟斤拷If the Miscellaneous IGN fuse is open, test the Ignition 1 voltage circuit, TCCM harness X2 pin 6, for a short to ground.
2. Ignition ON, engine OFF.
3. Using the Freeze Frame feature of the scan tool, review the Battery Voltage parameter when the DTC sets. The voltage should be above 12.0
V.
锟斤拷If the voltage is above 18.5 V, this is likely a vehicle issue such as an alternator problem, or the vehicle has been hooked up improperly
during a jump start. Refer to Symptoms - Engine Electrical (See: Starting and Charging/Testing and Inspection/Symptom Related
Diagnostic Procedures/Symptoms - Engine Electrical).
4. Using the Transfer Case Data Display feature of the scan tool, monitor the Battery Voltage parameter. The voltage should be above 12.0 V.
锟斤拷If the voltage is below 12.0 V, ensure that the battery is fully charged and working properly. Refer to Battery Inspection/Test (See:
Starting and Charging/Testing and Inspection/Component Tests and General Diagnostics/Battery Inspection/Test), Battery Common
Causes of Malfunction (See: Starting and Charging/Testing and Inspection/Component Tests and General Diagnostics/Battery Common
Causes of Malfunction) and Battery Electrical Drain/Parasitic Load Test (See: Starting and Charging/Testing and Inspection/Component
Tests and General Diagnostics/Battery Electrical Drain/Parasitic Load Test).
5. While monitoring the Battery Voltage parameter, start the engine. Rev the engine to greater than 3000 RPM. The voltage should remain
stable and below 18.5 V.
锟斤拷If the voltage is unstable or is greater than 18.5 V, ensure that the charging system is working properly. Refer to Charging System Test (
See: Starting and Charging/Testing and Inspection/Component Tests and General Diagnostics/Charging System Test).
Circuit/System Testing
Note: When test probing harness terminals, it is imperative to use the proper test probe from the most current version of the J 35616 - Kit.
Use of an improper test probe may deform the terminal, resulting in intermittent open conditions.
1. Key OFF. Disconnect the X3 harness connector at the TCCM.
2. Measure the voltage at the battery. The voltage should be above 12.0 V.
锟斤拷If the voltage is below 12.0 V, ensure that the battery is fully charged and working properly. Refer to Battery Inspection/Test (See:
Starting and Charging/Testing and Inspection/Component Tests and General Diagnostics/Battery Inspection/Test), Battery Common
Causes of Malfunction (See: Starting and Charging/Testing and Inspection/Component Tests and General Diagnostics/Battery Common
Causes of Malfunction) and Battery Electrical Drain/Parasitic Load Test (See: Starting and Charging/Testing and Inspection/Component
Tests and General Diagnostics/Battery Electrical Drain/Parasitic Load Test).
3. Install EL-49742 - harness. Test for B+ (+0.0/-0.5 V) between the 12 volt terminal (red) and the ground terminal (black) of EL-49742 -
harness.
锟斤拷If the voltage is less than the specified value, a vehicle wide issue is indicated. Inspect the battery positive circuit wire routing for chafed
wires or damaged inline harness connectors that could cause unexpected voltage drops.
4. Using the purple probe J 35616-4A, test for B+ (+0.0/-0.5 V) between the battery positive voltage circuit, TCCM X3 pin C, and the ground
terminal of EL-49742 - harness, black terminal.
锟斤拷If the voltage is less than the specified range, test the battery positive voltage circuit for an open/high resistance or short to ground.
5. Using the purple probes J 35616-4A, test for B+ (+0.0/-0.5 V) between the battery positive voltage circuit, TCCM X3 pin C, and the ground
circuit TCCM X3 pin D.
锟斤拷If the voltage is less than the specified range, test the ground circuit for an open/high resistance, short to ground or short together
condition.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Transfer Case High/Low Clutch Reset (See: Transmission and Drivetrain/Transfer Case/Testing and Inspection/Symptom Related
Diagnostic Procedures/MP 3023/3024-NQH - Transfer Case/Transfer Case High/Low Clutch Reset)
