Case Study: Jetta headlights are dim - DTC: C103615

March 8, 2023
The owner’s concern was that the headlights seemed dim.

Vehicle: 2015 Volkswagen Jetta GLI (163), L4-2.0L Turbo (CPLA), automatic transmission/transaxle

Mileage: 196,779

Problem: The owner’s concern was that the headlights seemed dim.

Case details: The technician connected a scan tool and found diagnostic trouble code (DTC) C103615 - Left Rear Level Control System Sensor Open Circuit/Short Circuit to B+.

At this point, the technician called ALLDATA Tech-Assist for some diagnostic help. One of the consultants advised that, if the vehicle ride height was incorrect, the headlamps may be improperly aimed, which would make headlights appear dim. He recommended checking the automatic headlamp range control values. If they were good, then check the basic setting of the headlamps.

He also advised testing the left rear level control system sensor (G76) by checking for a 5V reference and ground signal at the sensor. If they were good, then check the resistance of the sensor as it is moved from low to high and back. The resistance should change as the sensor arm is moved.

The technician checked the vehicle ride height, automatic headlight range control values and basic headlight settings. All were in specifications. When he checked the G76, the resistance did not change as the sensor arm was moved through its sweep.

Confirmed repair: He replaced the G76 and rechecked the basic settings for the headlamps. After the repairs, the headlights were bright and no DTCs returned. Fixed!

Reprinted with permission from ALLDATA.

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