U0146Lost Communication With Serial Data Gateway Module A
- Generic OBD-II code · Network
- Turns on the check-engine light
- How the car detects it
- 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.
- What you may notice
- 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)
- Likely causes
- 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
- RareGateway module hardware faulty
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.