HomeTrouble CodesU0481

U0481 — Invalid Data Received From Automatic Lighting Control Module

Generic OBD-II · all makesNetwork / communication

This code indicates that a module on the vehicle's network, typically the Powertrain Control Module (PCM), has received an illogical or corrupted data signal from the Automatic Lighting Control Module. It points to a communication issue where the lighting module is transmitting information that fails logical checks or is unreadable.

Symptoms

What causes it — most likely first

1. Automatic Lighting Control Module failure

The lighting module itself has an internal hardware or software fault, preventing it from formatting or transmitting valid data.

2. CAN bus wiring or connector issue

An open, short, or high resistance in the network wiring or connectors disrupts the data signal between the lighting module and the rest of the network.

3. Low system voltage

A weak battery or faulty charging system can cause the lighting module to drop offline or transmit corrupted data packets due to insufficient power.

4. Software incompatibility

A previously replaced module may have incompatible software or require programming to communicate properly on the specific vehicle network.

5. PCM/ECM failure

The receiving computer has an internal fault misinterpreting valid data, though this is an extremely rare cause for this code.

How it's diagnosed

  1. Scan all vehicle modules for additional U-codes to identify broader network communication failures.
  2. Inspect the wiring harness and connectors at the Automatic Lighting Control Module for damage, corrosion, or loose pins.
  3. Verify network termination resistance at the data link connector to rule out generic CAN bus failures.
  4. Check system voltage and battery health to ensure the lighting module is receiving adequate power and ground.
  5. Monitor the lighting module's data stream with a diagnostic tool to see if it transmits any valid parameters or is completely offline.

Code facts & related codes

SystemNetwork / communication
StandardizationSAE generic — identical on every make

Frequently asked

Can a bad battery cause a U0481 code?

Yes, low system voltage can cause electronic modules to malfunction and transmit corrupted or invalid data over the network.

Do I need to replace the PCM if this code is present?

No, replacing the PCM is almost never the correct fix. The fault lies with the lighting module, wiring, or power supply, and replacing the computer will not resolve the underlying issue.

Is it safe to drive with a U0481 code?

It may be unsafe if it affects the operation of your headlights, particularly at night or in poor weather. The vehicle should be inspected promptly to ensure proper lighting functionality.

Could water intrusion cause this issue?

Yes, water intrusion into the lighting module or its connectors can cause internal short circuits that corrupt the data signals, resulting in this code.