U1524 on Cadillac
Lost Communication With Right Headlamp on LIN Bus
U1524 on Cadillac vehicles indicates lost communication with right headlamp on lin bus. Au7o has documented this code across 1 Cadillac model — most commonly on XTS. A General Motors-specific network code. The headlamp control module (or headlamp leveling control module) stopped receiving the expected periodic message from the right headlamp over the LIN (Local Interconnect Network) bus — a single-wire, low-speed serial link between a master module and its subsystem devices. In practice the right headlamp, its leveling function, or its adaptive/DRL features may stop responding to commands. The lamp itself may still illuminate on a basic circuit even though the module can no longer talk to it. Typical repair costs on Cadillac range from $200 to $900, depending on the specific model and root cause.
Common Causes of U1524
- •Failed LED headlamp assembly or its integrated driver/ballast module (the LIN node itself)
- •Open, shorted, or corroded LIN serial data wire between the headlamp and the control module
- •Poor connection, water intrusion, or pushed-out pins at the headlamp connector
- •Loss of ignition power or ground to the right headlamp assembly
- •Faulty headlamp control module / headlamp leveling control module
- •Aftermarket headlamp or HID/LED retrofit that does not support LIN communication
U1524 on Cadillac by Model
Cadillac XTS(1 issue)
- Parasitic Battery Drain / Modules Not Entering Sleep Mode2013-2019
XTS owners frequently report the 12V battery going dead overnight or after a few days of sitting, caused by a control module failing to enter sleep mode and continuing to draw current with the ignition off. Common culprits on this platform include the radio/CUE (infotainment) module and the BCM. Repeated deep discharges then prematurely kill the battery and can trigger low-state-of-charge warnings and start-stop faults. GM issued service information for low-battery-state-of-charge conditions on 2018-2019 XTS/ATS/CTS.
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View U1524 across all makes →Frequently Asked Questions
What does U1524 mean on Cadillac?▼
U1524 stands for "Lost Communication With Right Headlamp on LIN Bus." A General Motors-specific network code. The headlamp control module (or headlamp leveling control module) stopped receiving the expected periodic message from the right headlamp over the LIN (Local Interconnect Network) bus — a single-wire, low-speed serial link between a master module and its subsystem devices. In practice the right headlamp, its leveling function, or its adaptive/DRL features may stop responding to commands. The lamp itself may still illuminate on a basic circuit even though the module can no longer talk to it. On Cadillac specifically, this code is documented across 1 model.
What causes U1524 on Cadillac vehicles?▼
Common causes on Cadillac: Failed LED headlamp assembly or its integrated driver/ballast module (the LIN node itself), Open, shorted, or corroded LIN serial data wire between the headlamp and the control module, Poor connection, water intrusion, or pushed-out pins at the headlamp connector, Loss of ignition power or ground to the right headlamp assembly, Faulty headlamp control module / headlamp leveling control module. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix U1524 on a Cadillac?▼
Repair costs on Cadillac range from $200 to $900, depending on the specific model and root cause.
Which Cadillac models have U1524 documented?▼
Au7o has documented U1524 on 1 Cadillac model: XTS.