U0149 code meaning
Lost Communication With Gateway D
What U0149 means
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.
U0149 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0149
- Group of modules in one domain does not answer
- Many U-codes stored at the same time
- Functions of the cut-off domain inoperative
Common causes of U0149
- Most likelyGateway D without power or ground
- PossibleOpen or shorted bus wiring, wet or corroded connector at gateway D
- PossibleLow battery voltage or battery disconnect (history code only)
- Less likelyGateway D internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Gateway moduleCAN bus wiring
What each part of U0149 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 49 | The exact fault in that area. |
What to do next
- Note U0149 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0149
What does U0149 mean?
U0149 means "Lost Communication With Gateway D". U0149 names Gateway D as the module whose messages no longer arrive. It is a generic code, so it means the same on every make.
Is it safe to drive with U0149?
Drive gently and only to a workshop. With U0149 the car can go into limp mode (reduced power) to protect itself.
Will U0149 fail an emissions test?
U0149 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U0149 to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will U0149 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.