What are the common causes of U0149?

Faulty wiring between the PCM and Gateway Module D. A failed Gateway Module D. Corrosion or water damage at the Gateway D connector. Software in Gateway D that has dropped off the bus. Physical damage to the harness at Gateway D.

Inspect the wiring between the PCM and Gateway Module D. Monitor the network on a scan tool for Gateway D traffic. Check the Gateway D connector for water or corrosion. Update or reflash Gateway Module D. Replace Gateway Module D if it stays offline. Clear the code and retest.

U0149

Lost Communication With Serial Data Gateway Module D

System: Network communication (U code)
Lamp: Check Engine Light
Category: Network Communications

What it means

U0149 means Lost Communication With Serial Data Gateway Module D.

Where it lives

For U0149, the description names the module as the part involved.

Check these first

Faulty wiring between the PCM and Gateway Module D
A failed Gateway Module D
Corrosion or water damage at the Gateway D connector
Software in Gateway D that has dropped off the bus
Physical damage to the harness at Gateway D

What to do next

Inspect the wiring between the PCM and Gateway Module D
Monitor the network on a scan tool for Gateway D traffic
Check the Gateway D connector for water or corrosion
Update or reflash Gateway Module D
Replace Gateway Module D if it stays offline
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.