U0147
Lost Communication With Serial Data Gateway Module B
Communication / gateway
Generic OBD-II
High
What it means
U0147 means a controller has lost communication with serial data gateway module B. The gateway relays messages between the vehicle's separate networks, so when it drops offline, modules on different buses can stop talking to each other. Expect multiple warning lights and inoperative features; how much is affected depends on what the gateway routes.
High
Can I keep driving? Often impaired — the gateway routes data between the vehicle's networks, so losing it can knock out many modules at once; check that key systems respond before driving.
Common symptoms
What you'll notice
- Several warning lights or messages across different systems
- Multiple modules unreachable by a scan tool
- Features that rely on cross-network data stop working
- Intermittent, widespread electrical glitches
Common causes
Most likely first
- Loss of power or ground to the gateway moduleLikely
- Damaged wiring or connector at the gatewayCommon
- Failed gateway moduleCommon
- CAN bus fault on one of the networks the gateway linksLess often
- Software or configuration issue after a module replacementLess often
How to diagnose & fix
Work through it in order
- Scan all modules and note the pattern of no-communication codes.
- Check the gateway module's power, ground, and connector first.
- Inspect the bus wiring feeding the gateway for shorts or opens.
- Verify the gateway software and configuration are correct, especially after recent work.
- Repair the wiring or replace and program the gateway as needed, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with U0147?+
It depends what the gateway routes on your vehicle. Because it can disable many systems at once, have it diagnosed before relying on the car.
Can I just clear U0147?+
It clears but returns while the gateway is offline. The underlying power, wiring, or module fault has to be fixed.
Related codes
Often seen with U0147
Read & clear U0147 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX