Mercedes Front left Malfunction or U100887 LIN BUS 1 is faulty - solved

In this video I am showing process how I dealt with error stating FRONT LEFT MAULFUNCTION CONSULT WORKSHOP or showing on diagnostic as LIN BUS 1 is Faulty.
In this scenario it was just ground cable that was loose/disconnected at some point. However I am showing electrical schematic for front passenger weight module with colour coding and also where the cables lead to.
First step is always check if the fuse is OK.
Then check if the connector is not loose.
Check for connector or cable damage as when the seat moves up & down this is quite common fault.
Check for 12V+ voltage on the connector and proper ground
Check LIN BUS 1 wire for continuity
Leave the weight module replacement as last option to save £££

[@baileycocks]

I got this error on my A45. Mercedes dealership quoted me $1900 AUD. Definitely going to check all these cables now.

[@sabastianrobar1269]

Many thanks. Been trying to solve this for about a year now but there aren't many in depth videos like yours!

[@yus2713]

Thank you solved my left airbag issue, was fuse wrong way round.

[@Andy2x4]

Thank you so much. You’ve just saved me £900 after the garage were going to charge me for a new seat pad. If it weren’t for this video I’d never have thought to check the fuse (which was loose from hardwiring a dash cam). Dash cam removed and fuse in - works perfectly after light reset. Thanks so much. Very grateful.

[@maximlake9280]

I am glad you have been able to work it out. It would be interesting to know if the garage would found the same and if they still would charge that ammount for cost of €0.20 fuse

[@Ice1371]

Andrew R And thanks to you too as i also had a dash cam hard wired and it was the cause of the fault. Saved me a fortune 👍🏼

[@Andy2x4]

@@Ice1371 oh wow, that’s great news, glad my comment could help you. Together, we have saved a fortune!

[@techqueries3881]

I am worried now, as mine has the same thing! I have c180 coupe here in the UK and it had a factory recall on the airbag, so i thought it was related. After the dealer did the work, they said there is an alert with the passenger recognition seat pad, and the manufacturer doesnt make them any more? and they are trying to get hold of the manufacturer to find out. £900 is immense!

[@pattiwysocki6378]

Nicely explained. Thank you.

[@GainKnowledge-rw9nw]

Thank you for you video

[@proauto5716]

Thanks for video

[@minamousa]

where do I get the wiring diagram? I have the same fault on my 2013 C250 (no fuse box in the passenger or the driver sides!)

[@vanessap4380]

I had this indicator come on after some water leaked onto the seat. Any advice? Thank you

[@silvergold08]

Hey I changed the steering wheel on my 2020 g wagon this error popped up im sure it’s because I didn’t disconnect the battery while installing. If I disconnect the battery do you think it will reset?

[@canoaslan1011]

Thanks, helped alot

[@maximlake9280]

Great. It's interesting to see how many people have the same problem. Mercedes should rethink this particular design to make it more resilient against damage or such simply failures with this seat weight device.

[@automotivenene3482]

Nice vid. What software you use for your schematics? Cheers.

[@dayshajolliff2]

Hello what number fuse is the front left malfunction I seen which one is the right just haven’t for left

[@danielfriday9204]

Nice info

[@andreializeu93]

Mine is cutting the servo and also sends a handbrake error as well.

[@Stratulatii]

Hello, I had some issues with the cable under the console. I managed to put it back together, but now I have 2 front left and right malfunctions without any DTC found. I already checked the fuses, and double-checked the wires, but I see nothing wrong there, what should I do? Thank you!

[@tiptopmechanic1155]

You have disconnected or damaged some of the wires. Check connectors of all properly plugged in. Otherwise you have short circuit with some wires.

[@toeknee5703]

Right?!? I am a fleet manager for a DSP which has 19 Mercedes Sprinter diesels and 11 gas Mercedes Sprinters. We have this FLM multiple times a week. So far it’s been the seatbelt and now a safety feature inside the driver door. I refuse to put my drivers in a van with an SRS issue or even a check engine light on! These vans were not made for deliveries 7 days a week 10 hr days and 25 to 35 stops an hour!

[@FinancePro203]

Hello - quick question. I have a 2013 C300. I removed driver side airbag in steering wheel to change out a trim piece, I now have a code. Is this something that I can reset myself? Dash showing front left malfunction. Thank you!

[@AliJohnAfandi]

Did you fix it? I changed some buttons on my 07 s550 and put back the airbag in steering wheel but now is showing “malfunction on left side” with airbag symbol

[@FinancePro203]

@@AliJohnAfandiYes - I had to buy a diagnostic tool that had the capability of resetting the SRS system. Cheap tools will not include this functionality.

[@Bawwwstinnn1997]

@tiptopmechanic My drivers seat (bottom seat) had a rip in it so I had to disconnect the seat to replace with new one. After completion I got the error message “front left malfunction service required” came up. I did purchase reader with SRS and got “no trouble codes” Any suggestions? Would your video get rid of “front left malfunction service required “ message? Thank you in advance!

[@tiptopmechanic1155]

Standard diagnostic tool won't hava capability to do this. Check all the wires and connectors. If it was 100% working before and all you did some replacement that means you must done something to the wires.

[@Bawwwstinnn1997]

@@tiptopmechanic1155 Ahh thank you so much I appreciate your reply back. And yes I do agree something must of happened with the wires during the removal of the seat. Thank you again !

[@ry2054]

@@Bawwwstinnn1997 did you ever find out what happened ? Same exact issue that happened with you happened with me today i drop my car off to get a rip fixed and the malfunction thing popped up

[@Bawwwstinnn1997]

@@ry2054 Oh no do you mean the malfunction message popped up after you the rippped seat fixed? Because if you took it to a place to have it fixed they need to get rid of that malfunction message for you. And yes I did find out why it happened, supposedly when my husband replaced the ripped sear he was to disconnect the battery beforehand. I have to bring it to the dealer to have them reset it. You should bring it back to who fixed it.

[@sandraaakua]

Mines says this , but my horn also doesn’t work after this showed up . Is that another problem or is this the reason ?

[@tiptopmechanic1155]

Check fusea

[@preciousharvey4692]

What about 2019 gla

[@dashtyATG]

That's a great video I was working on a Benz 2018 s560 wiv code error B1F7D54 and saying front left malfunction consult workshop on the dash any idea please? Do you think it's the same issue ?

[@tiptopmechanic1155]

Either sensor or no power to the sensor

[@dashtyATG]

@@tiptopmechanic1155 thank you

[@daviderhahon]

C-class 2016 model

[@siaweixiong707]

Sir, Mercedes c class w205 coupe climate control fault , it shown U100800 LIN bus 1 has malfunction . What’s the possible fault it occur ?

[@tiptopmechanic1155]

Is your climate control working ? Is there power ? Check for 12V+ cable and ground first. If all OK look for the schematics and find LIN cable and check for damage.

[@glasser2819]

@@tiptopmechanic1155 great pro-grade advice 👏 👍

[@ionutpreda1150]

@@tiptopmechanic1155 hi , I changed the steering wheel from a 2011 w218 and put on the facelift, my orders don't work , on the tester when I wanted to clear the airbag error I came across the u1008-lin bus error ..

[@tiptopmechanic1155]

@@ionutpreda1150 Different connector pinout

[@patriciocardoso2083]

Código de erro mercedes v220 U100800 sabe me dizer. Ar condicionado não funciona

[@Trey_Luis]

I cannot even move right now and I’m in Manhattan. Help

[@darrenjohnson1129]

Literally plugged my seats out of the yellow sockets yesterday, now both seats give malfunction message 🤦‍♂️🤷‍♂️

[@sidihumzah8940]

Is there a way to contact you or hire you for your services?

[@tiptopmechanic1155]

[e-mail]

[@andyhookigs4586]

Hello friend. Is the same in the w204?? I have the same code. Thanks 👍

[@tiptopmechanic1155]

Try to unplig cinnector unde passenger seat. If the error stays then you havd identified the issue as no communication is going to weight sensor.

[@andyhookigs4586]

@@tiptopmechanic1155 thanks for your quick response and help. The sensor was changed because the error was the seat mat sensor ( I've got the diagnostic machine ) but now with the new sensor appears that fault of line can bus 1. Thanks my friend 🤝🤝👍

[@tiptopmechanic1155]

@@andyhookigs4586 then the wire is damaged somewhere. Its going all the way to Airbag module. I would unplug Airbag module and try to check for continuity on that wire between connector at Air bag module and connector at the sensor. It's 1x wire that is going all the way up there. Also check for ground maybe try give ground from elsewhere to the weight sensor module. Also check if it has 12V coming once ignition is ON.

[@andyhookigs4586]

@@tiptopmechanic1155 i will check and let you know. thanks 🙏🙏🙏🙏

[@andyhookigs4586]

@@tiptopmechanic1155 hello. Sorry for delay in answering, but I lost the link and I couldn't find it so easy 😅. Apologies. I changed the sensor mat because it was one of the codes and that code disappeared, but now i keep with the u100887 about can bus line 1. I have a look the wires but I hadn't too much time. Thank you