U0149: Lost Communication With Gateway D

U0149 names Gateway D as the module whose messages no longer arrive. Vehicles with several gateways split the network into domains, and each gateway routes traffic between its own bus segments; losing D therefore cuts off the domain it serves. Following GM's generic U0100-U02FF logic, a receiving module stores the code when the expected periodic message with the sender's availability is missing while voltage is normal. No manufacturer documents U0149 publicly, and GM only lists U0146 for a single gateway. U0146 to U0148 cover gateways A to C, U0150 the fifth one. A history-only entry after a battery disconnect or flat battery is often harmless; an active one usually comes with many other U-codes. No MIL as a rule.

Medium severity. Can I keep driving?It depends on which control module has dropped out. If it affects the engine, brakes, or steering, do not continue your trip: call for roadside assistance.

Symptoms

Group of modules in one domain does not answer
Many U-codes stored at the same time
Functions of the cut-off domain inoperative

Most likely causes

Gateway D without power or ground
Open or shorted bus wiring, wet or corroded connector at gateway D
Low battery voltage or battery disconnect (history code only)
Gateway D internally faulty

What to check, in order

Start with the simplest. You can tick off each step.

Check the battery and terminals, and read the codes from all control modules with a multi-system scanner
Identify which control module is not responding and check its fuses, power supply, and grounds
Disconnect add-on accessories, such as alarms or trackers, and read the codes again
Inspect the network connectors for moisture or bent pins
Measure the network's resistance and signal using the manufacturer's wiring diagram

Good to know

Repair difficulty: hard
It can trigger limp mode.

What each character of U0149 means

U: Communication network
0: Generic code: same on every make
1: Subsystem depends on the code range
49: Specific fault in that system

Frequently asked questions

Can I keep driving with code U0149?

It depends on which control module has dropped out. If it affects the engine, brakes, or steering, do not continue your trip: call for roadside assistance.

What causes code U0149?

The most common causes are: gateway D without power or ground; open or shorted bus wiring, wet or corroded connector at gateway D; low battery voltage or battery disconnect (history code only).

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.