Headlamp

Adaptive Headlighting

Pinpoint Test K: DTC U0140

Normal Operation

- DTC U0140 (Lost Communication With Body Control Module (GEM))- an on-demand DTC that sets when the Headlamp Control Module (HCM) does not receive ignition state or headlamps on/off messages from the Body Control Module (BCM) for longer than 5 seconds.

This pinpoint test is intended to diagnose the following:

- Communication network concern

- BCM (Body Control Module)

- Left headlamp assembly

PINPOINT TEST K : DTC U0140

K1 VERIFY THE CUSTOMER CONCERN

- Ignition ON.

- Verify there is an observable symptom present.

Is an observable symptom present?

Yes
GO to K2.

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

K2 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 K3.

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.

K3 CHECK FOR DTCs U3003:16 AND U3003:17 FROM THE BCM (Body Control Module) SELF-TEST

- Retrieve the continuous memory DTCs from the BCM (Body Control Module).

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

Yes
REFER to Body Control Systems.

No
GO to K4.

K4 RECHECK THE HCM (Headlamp Control Module) DTCs

NOTE: If new modules were installed prior to the DTC being set, the module configuration may be incorrectly set during Programmable Module Installation (PMI) or the PMI (Programmable Module Installation) may not have been carried out.

- Enter the following diagnostic mode on the scan tool: HCM (Headlamp Control Module) Self-Test.

- Clear the DTCs and repeat the HCM (Headlamp Control Module) self-test.

Is DTC U0140 still present?

Yes
GO to K5.

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.

K5 CHECK FOR DTC U0140:87 OR DTC U0140 SET IN OTHER MODULES

- Clear the 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 U0140:87 or DTC U0140 set in any other module?

Yes
INSTALL a new BCM (Body Control Module). CLEAR the DTCs. REPEAT the HCM (Headlamp Control Module) self-test.

No
INSTALL a new left headlamp assembly. REFER to Headlamp Assembly . TEST the system for normal operation