Pinpoint Test P: DTC U0140 - Lost Communication With Smart Junction Box (SJB)

Interior Lighting

Pinpoint Tests

Pinpoint Test P: DTC U0140 - Lost Communication With Smart Junction Box (SJB)

Normal Operation
- DTC U0140 (Lost Communication With SJB) - set by the Interior Lighting Control Module (ILCM) if data messages received from the SJB over the Medium Speed Controller Area Network (MS-CAN) are missing. For a complete list of all network messages, refer to Information Bus.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- ILCM



PINPOINT TEST P: DTC U0140 - LOST COMMUNICATION WITH SJB

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P1 VERIFY CUSTOMER CONCERN


- Ignition ON.
- Verify that there is an observable symptom present.
- Is an observable symptom present?

Yes
GO to P2.

No
The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

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P2 CHECK THE COMMUNICATION NETWORK


- Enter the following diagnostic mode on the scan tool: Network Test .
- Carry out the network test.
- Does the SJB pass the network test?

Yes
GO to P3.

No
REFER to Information Bus.

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P3 RECHECK THE ILCM DTCs


- Clear the DTCs. Repeat the ILCM self-test.
- Is DTC U0140 still present?

Yes
GO to P4.

No
The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

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P4 CHECK FOR DTC U0140 or U0140:00 SET IN OTHER MODULES


- Clear all DTCs.
- Ignition OFF.
- Ignition ON.
- Wait 10 seconds.
- Enter the following diagnostic mode on the scan tool: Self-Test .
- Retrieve the continuous memory DTCs from all modules.
- Is DTC U0140 set in the Driver Seat Module (DSM) or the Driver Door Module (DDM)?

Yes
INSTALL a new SJB. REFER to Body Control Systems. CLEAR the DTCs. REPEAT the self-test.

No
INSTALL a new ILCM. REFER to Interior Lighting Control Module (ILCM) Interior Lighting Control Module (ILCM). TEST the system for normal operation.

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