Code Definition

U1504 — Lighting Control Sensor LIN Timeout (Vehicles with Auto Light Function)

System: Network Communication  |  Type: Manufacturer-Specific  |  Make: Mitsubishi

About U1504

U1504 is a manufacturer-specific network communication diagnostic trouble code recorded for Mitsubishi vehicles. It belongs to the U-prefix family of codes, which covers inter-module network communication (CAN, LIN, FlexRay, or similar) faults.

When U1504 is stored, the module has detected a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: Network (U) codes report communication faults between modules. When diagnosing U-codes, checking the vehicle's CAN bus integrity, supply/ground at each module, and reading all modules for related faults is usually the first step.

U1504 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

On Mitsubishi vehicles fitted with the automatic light function, the lighting control sensor sits in the base of the windscreen, usually behind the rear view mirror, and reports ambient light level to the ETACS ECU over a LIN bus rather than over CAN. LIN is a single wire, low speed serial link, so the sensor needs only a power feed, a ground and one communication wire. U1504 is set when the ETACS ECU receives no message at all from the lighting control sensor within the expected time window, which is a complete loss of communication rather than a corrupted message. The customer notices the au...

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