Inspection and Verification

Smart Junction Box (SJB)

Inspection and Verification

1. Verify the customer concern.

2. Visually inspect for obvious signs of electrical damage.

Visual Inspection Chart






3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

4. NOTE: Make sure to use the latest scan tool software release.
If the cause is not visually evident, connect the scan tool to the Data Link Connector (DLC).


5. NOTE: The Vehicle Communication Module (VCM) LED prove-out confirms power and ground from the DLC (Data Link Connector) are provided to the VCM (Vehicle Communication Module).
If the scan tool does not communicate with the VCM (Vehicle Communication Module)

- check the VCM (Vehicle Communication Module) connection to the vehicle.

- check the scan tool connection to the VCM (Vehicle Communication Module).

- refer to - No Power To The Scan Tool, to diagnose no power to the scan tool.


6. If the scan tool does not communicate with the vehicle:
- verify the ignition is ON.
- The air bag warning indicator prove-out confirms ignition ON (other indicators may not prove ignition ON). If the ignition does not turn on, refer to Steering Column to diagnose no power in RUN.

- verify the scan tool operation with a known good vehicle.

- refer to Information Bus to diagnose no response from the PCM.


7. Carry out the network test.
- If the scan tool responds with no communication for one or more modules, refer to Information Bus.

- If the network test passes, retrieve and record the continuous memory DTCs.


8. Clear the continuous DTCs and carry out the self-test diagnostics for the SJB (Smart Junction Box).

9. If the DTCs retrieved are related to the concern, go to DTC Charts. For all other DTCs, refer to Diagnostic Trouble Code (DTC) Chart . Body Control Systems

10. If no DTCs related to the concern are retrieved, GO to Symptom Chart. Symptom Related Diagnostic Procedures