U0483

Code

Generic U — Network/User

Invalid Data Received From Lighting Control Module - Front

Brand: Generic

Type: U — Network/User

Views: UK: 27 EN: 48 RU: 26

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Page language: EN

Faulty front Lighting Control Module (LCM)
Poor connector or pin contact at the LCM or nearby junctions (corrosion, bent pins)
Damaged wiring (open, short to ground, short to battery) on CAN or module power/ground circuits
Low battery voltage or poor battery/charging system performance
CAN bus termination or wiring fault (high resistance, short between CAN_H and CAN_L)
Software mismatch or corrupted module programming

Illumination faults of front lights (headlamps, DRL, turn lamps) or inconsistent operation
Warnings or message on dash related to lighting or communication
Other modules reporting related U-codes or loss of functions that depend on front LCM
Intermittent or permanent failure of some front lighting functions
Possible MIL or stored multiple network-related DTCs

Use a capable scan tool to read all U- and B- codes and check freeze frame/ignition status.
Verify battery voltage is within normal range (12.4–14.5 V with engine running) before diagnosing.
Visually inspect the front LCM connector(s), harness for damage, corrosion, or signs of water ingress.
Check module power and ground pins for proper voltage and low resistance to chassis ground.
Verify CAN bus communication using a scan tool – confirm the front LCM appears on the network and note any other modules with communication faults.
Measure CAN bus termination resistance (typical ≈ 60 ohms between CAN_H and CAN_L with ignition on).

Battery/supply voltage to LCM: ~12 V (ignition off) and ~12.4–14.5 V running
Module ground continuity: near 0 ohms to chassis ground
CAN_H idle voltage (typical): ≈ 2.5 V
CAN_L idle voltage (typical): ≈ 2.5 V
CAN dominant state: CAN_H rises and CAN_L falls (typical dominant differential ≈ 2 V; CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V)
Termination resistance between CAN_H and CAN_L: ~60 ohms (two 120 ohm terminators in parallel)

Record the exact DTC, any freeze frame data and note vehicle conditions when the code set (ignition state, lights on/off).
Check battery and charging system voltages. Low voltage can corrupt communication — correct if out of range.
Scan the vehicle network to see if the front LCM is present and whether other modules show communication faults or related U-codes.
Visually inspect the LCM connector and harness for water, corrosion, damaged insulation, or bent pins. Repair any physical damage.
With ignition on, measure supply voltage and ground at the LCM connector. Repair poor power/ground before further testing.
Check CAN bus voltages at the LCM connector: verify CAN_H and CAN_L idle and dominant voltages and check termination resistance (~60 Ω).
If CAN voltages are abnormal, trace wiring for opens/shorts to power or ground, damaged insulation, or shared splices. Disconnect suspect modules to isolate the fault.
If wiring and vehicle power/ground are good but communication is still invalid, perform a bench or module replacement test per manufacturer procedures (reprogram or swap with a known-good unit if available).
Reprogram or update module software if an update is available and the manufacturer bulletin indicates a software fix.
After repairs, clear codes and operate the vehicle through conditions that caused the code to confirm the fault is resolved. Re-scan for related codes.