Service Headlamp System Message

A Service Headlamp System message may be displayed on the Driver Information Center (DIC) on some 2020-2023 Corvette models equipped with the Front Lift System (RPO E60). (Fig. 8) The message may be displayed without any noticeable symptoms on the vehicle. All headlamps and exterior lighting functions may work correctly and no DTCs may be set.

 

Fig. 8

 

To address the Service Headlamp System message, closely inspect all areas of LIN bus 13 / circuit 2859 that runs from the headlamp capsules to the Body Control Module (BCM). (Fig. 9) The purpose of this circuit is to command the leveling portion of the headlamps up and down in response to the activation of the front suspension lift system.

 

Fig. 9

 

The front suspension position sensors provide the K218 Front Suspension Leveling/Lifting Hydraulic Power Pack Module with suspension position information, which sends this information through serial data to the BCM. The BCM responds by sending this information through serial data on LIN bus 13 to each headlamp assembly. The headlamp assemblies respond by adjusting the headlamp low/high beams to the appropriate position to compensate for the suspension position of the vehicle.

When the vehicle is started, the BCM sends out a test signal to each headlamp to confirm the LIN bus is working correctly. If the message is not received and responded to, the Service Headlamp System message is displayed in the DIC.

When checking the LIN bus, there is not a way to tell where an issue may exist in the circuit. It will be necessary to physically inspect the entire circuit, looking for any open or ground concerns, on both sides of the vehicle.

Refer to #PIC6512 for more information.

– Thanks to Matt Bierlein