Pinpoint Test N: DTC U0140

Interior Lighting

Pinpoint Tests

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

PINPOINT TEST N: DTC U0140

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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.

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N2 CHECK THE COMMUNICATION NETWORK

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

Yes
GO to N3.

No
REFER to Module Communications Network Testing and Inspection, The BCM Does Not Respond To The Scan Tool.

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N3 RECHECK THE ILCM DTCs

- Enter the following diagnostic mode on the scan tool: ILCM Self-Test.
- Clear the DTCs, wait 10 seconds, and repeat the ILCM 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.

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N4 RETRIEVE THE RECORDED DTCs FROM THE BCM SELF-TEST

- Check for recorded BCM DTCs from the self-test.
- Is DTC U3003:16 or DTC U3003:17 recorded?

Yes
REFER to Multifunction Electronic Modules Multifunction Electronic Modules.

No
GO to N5.

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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. REFER to Multifunction Electronic Modules Service and Repair. TEST the system for normal operation.

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

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