Pinpoint Test N: DTC U0140

Interior Lighting

Pinpoint Test N: DTC U0140

Normal Operation

- DTC U0140 (Lost Communication With Body Control Module (GEM)- sets when the Interior Lighting Control Module (ILCM) detects data messages are missing or not received from the Body Control Module (BCM) over the Medium Speed Controller Area Network (MS-CAN).

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- BCM (Body Control Module)

PINPOINT TEST N : DTC U0140

N1 VERIFY THE CUSTOMER CONCERN

- Ignition ON.

- Verify that there is an observable symptom present.

Is an observable symptom present?

Yes
GO to N2.
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.

N2 CHECK THE COMMUNICATION NETWORK

- Enter the following diagnostic mode on the scan tool: Network Test.

- Carry out the network test.

Does the BCM (Body Control Module) pass the network test?

Yes
GO to N3.
No
REFER to Information Bus, The BCM (Body Control Module) Does Not Respond To The Scan Tool. Pinpoint Test I: The Body Control Module (BCM) Does Not Respond To The Scan Tool

N3 RECHECK THE ILCM (Interior Lighting Control Module) DTCs

- Enter the following diagnostic mode on the scan tool: ILCM (Interior Lighting Control Module) Self-Test.

- Clear the DTCs, wait 10 seconds, and repeat the ILCM (Interior Lighting Control Module) self-test.

Is DTC U0140 still present?

Yes
GO to N4.
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.

N4 RETRIEVE THE RECORDED DTCs FROM THE BCM (Body Control Module) SELF-TEST

- Check for recorded BCM (Body Control Module) DTCs from the self-test.

Is DTC U3003:16 or DTC U3003:17 recorded?

Yes
REFER to Body Control Systems
No
GO to N5.

N5 CHECK FOR DTC U0140 OR DTC 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 or DTC U0140:00 set in any other module?

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