U0146 code meaning
Lost Communication With Serial Data Gateway Module A
Network system Generic code U01xx codes Check engine light
What U0146 means
U0146 means the first gateway, the node that routes messages between bus segments, is silent; GM calls it serial data gateway module, Ford, Audi and GM's tables just Gateway A. GM's 2019 ECM expects message $3CF at least every 10 s with the battery above 11 V and treats a gap as Type B, so the MIL lights if it recurs on a second trip. Field case: on 2017 Silverado, Sierra, Tahoe, Yukon and Escalade the gateway's processor could stay powered yet fall silent on every CAN channel, leaving dead gauges, no crank or stalling plus U0146 and many other codes; pulling its fuse for a minute helps until new software, bent or backed-out terminals are the other cause (PIT5586G). On the 2022-24 Audi Q4 e-tron the engine unit logs U014600 when the application server inside the gateway has a hardware or software fault. U0447 is invalid gateway data.
U0146 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0146
- Instrument cluster gauges dead or fluctuating
- No crank, no start or stalling
- Many U-codes in several modules and multiple warning messages
- MIL on (GM Type B)
Common causes of U0146
- Most likelyGateway software hangs and stops routing although powered (GM PIT5586G, Audi ICAS)
- PossibleBent, backed-out or loose terminals at the gateway connectors
- PossibleGateway fuse, power or ground missing
- Less likelyGateway module hardware 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 U0146 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 46 | The exact fault in that area. |
What to do next
- Note U0146 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 U0146
What does U0146 mean?
U0146 means "Lost Communication With Serial Data Gateway Module A". U0146 means the first gateway, the node that routes messages between bus segments, is silent; GM calls it serial data gateway module, Ford, Audi and GM's tables just Gateway A. It is a generic code, so it means the same on every make.
Is it safe to drive with U0146?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will U0146 fail an emissions test?
U0146 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 U0146 to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will U0146 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.