3 Lines Fault - Smart Fortwo Passion 84 BHP 451 2008 - An Update

In this video I give an update on this persistent fault with my 2008 Smart Fortwo Passion 84 BHP 451. The car actually broke down in use and is now too unreliable to drive.
The SAM unit (Signal Acquisition Module) was previously carefully dismantled and I discovered several failed solder joints on the circuit boards within the SAM unit which I re-soldered (re-flowed). Video here: • Smart Fortwo 451 - SAM...
I have also replaced the clutch actuator with a new Sachs component. Shorts video here: • Fortwo Clutch Actuator...
There is no water ingress to the vehicle which could harm/affect the TCM (Transmission Control Module and the carpet/area beneath is clean and dry.
I previously scanned the vehicle for trouble codes/fault codes and the below were found:
N15/6 Sprintshift control module (2 DTCs)
P1800 Implausible transmission data.
P2802 Signals from incremental sensor of component 'M17 (Gear motor)' are implausible.
N47-5 (ESP control unit) (1 DTC)
Fault in CAN communication with control module 'N15/6 (Sprint shift control module)'.
I will be checking the engine earth cable, battery, alternator output and wiring loom to clutch actuator and gear shifter motor. I may even need to drop the engine undertray to examine the ECU for ABS/ESP. Further updates to follow.
If you enjoy my videos and would like to help support Auto Knight in creating similar content, please click here: www.buymeacoff...
Disclaimer - Please be advised that my videos are not instructional and are merely footage of me, with many years of motor trade experience, carrying out vehicle repairs and maintenance. Please conduct your own research, ensure you have the correct tools/necessary expertise and undertake your own due diligence before carrying out vehicle repairs. If in doubt, entrust an automotive technician / car mechanic.

[@bertlzansinger]

The problem with the Smart system as a whole is that these bars can have several causes. There is a lot of knowledge (e.g. forums, evilution) that can provide additional information. Best of luck (and keep us posted)!

[@donandannie4u2]

I would love to buy one of these here in Buffalo, NY State. 61 year old widower who just wants a good, SMALL, first and only car to get back and forth to work. I love the idea and look of these little buggers but after watching these amazing and incredibly informative vids, like yours Auto Knight, I'm a tad hesitant to purchase a Smart Car now. I hear they do run well in snow but the exposed wiring under neath leading to the actuator scares me a bit as well

[@olebendtsen6117]

The Smartfortwo absolute does not run well in snow - for snow You need a car with frontwhell drive. I have driven VW-Beetle too - also absolute dangerous and terrible in snow!

[@MarkGib]

Watching with interest, I'm taking the SAM out for inspection / repair today and also looking at the tail light looms. Good luck 👍

[@juliangroves4446]

informative as always... great to see the actual reality of problems.keep it up.

[@CrustyRestorations]

I've had my smart brabus 6 years now, love it, parking is a dream. Not sure I could cope with some tank of an suv. But I've had all sorts of faults over the years, and only expensive Mercedes garages will investigate. Most garages won't touch them, but future classics.. hopefully you stick with it... 👍

[@min47pgl]

Hi - I had a really similar problem - I needed a new clutch as well as actuator. In tbis case I think it would be best to find a garage with MB STAR diagnostics. I know there is a smart specialist called Smart Sport who should be able to plug in and diagnose exactly what the issue is and also correctly teach in the clutch actuator. Thanks for all your content on the 451 and good luck

[@icecube2T8]

Don’t know if you see the comments, I’ve got one myself and after driving sometimes I get an eml light with code p0900 p0805 and car is like a jack in a box driving through the gears? Leave the car for an hour or so and she’s good as gold. Did pull the actuator and re grease but still can’t clear the codes as the eml light comes back on after ignition off/on You obviously the smart guru so hopefully you might be able to shed a bit of light 😁 Great videos by the way

[@autoknight747]

There are so many things that can cause such issues on these and it is incredibly hard to know without going through diagnostic processes. From clutch failure (they break up), to actuator failures, wiring faults/breaks/shorts, bad SAM joints - the list goes on.

[@jurgenberg5941]

Ich hatte ähnliche Probleme mit meinem Smart, bei mir war der Bremslichtschalter defekt. Funktionieren deine Bremslichter? Viel Erfolg bei der Fehlersuche! Gruß Jürgen

[@sussexexternalcleaning6276]

Good luck bud ! Hopefully it’s not too much of a long process

[@paultaienao3988]

Thank you Auto Knight for all your videos. I really appreciate all the information. On your last update, as far as the 3 lines transmission issue, you mentioned more than likely it was the ground strap. Now you mentioned in the previous video that you may have put up a secondary strap And I’m wondering if you did that or you just kept the original strap on and just cleaned it up. 👍👍👍

[@autoknight747]

I didn’t need the additional earth strap in the end. Cleaning up the original until it was shining bright was sufficient. 👍

[@dps1983]

That’s a shame the Sam unit didn’t cause this problem .It will be worth taking wiring loom completely out and check for continuity.You will need to remove the passenger seat otherwise you won’t be able to removed the plug from gearbox module .Maybe some contacts are corroded or the module is gone under the passenger seat under the carpet . All the best in fixing this car up .

[@N11GAMES-vv9lu]

hello friend, under the left seat of your smart is the transmision ecu box. Most probably has got water on it or may be just wet somehow. dry it and you are good to go. 90% it will fix your problem. good luck

[@autoknight747]

No water leak. Bone dry.

[@TheEmporiums]

I had the 3 lines on a 2004 model. Still went through all the gears just didn't display what gear it was in. Plugged it into a diagnostic machine selected the gear box and told it to go into neutral. Could hear the gearbox click away and up popped the dashboard gear display.

[@dps1983]

I also come across very bad behaviour from other road users (tailgating, cutting away )and my smart is working .

[@michaelglynn2638]

Same here, it's as though small cars and their drivers deserve no respect! Bizarre.

[@jimmyadams628]

Best of luck 😊

[@MrMr123]

I'm frustrated too.... hahahah... Hope you find the problem

[@michaelglynn2638]

The small white cap on the gear motor. I read on a forum that putting lubricant down there cured a gear shifting problem. Obviously I'm not sure if there's any credibility to this but I did wonder what that cap is there for.

[@autoknight747]

The white cap is actually a cover for the gearbox vent. Once the cap is removed it leads straight into the transmission via the gear motor. Unfortunately any lubricant sprayed in there would ultimately reach the gearbox oil.

[@danielsun7214]

Nowadays when your smart breaks down it's like mine breaking down, I really hope I can solve the problem. Ps I also noticed a certain aggressiveness towards the little smart in traffic, poor idiots!

[@gigmaresh8772]

I certainly hope you get knighted for all your efforts

[@autoknight747]

Haha. I think I’ll have to do a bit more than push a few videos!

[@williamrae9954]

Just bought a wee convertible...dropping the engine out for either a BMW K1600 6 cylinder, or a Honda 1200 V4 DCT...whatever turns up at the right price

[@benleipe]

Hi, i'm Ben from Germany. I Love my 451 CDI. It has already run 325000 km since 17 years. Now i had the 3 lines of Doom on my display. After several trys i swaped the battery. It was still the original from delivery. Now, it drives like a new car, just as you described it after cleaning the contacts from your earth. I hope that was the cause of the trouble. Since 500 km it runs perfectly. Habe you tried it with a new battery?

[@autoknight747]

Hello - the battery is strong and withstood testing. I have recently replaced the gear shifter motor as the vehicle had completely failed. It is now good. Video will go live on Friday.

[@David-uu8vz]

Did u ever get to bottom of the p1800 code cheers lookn 4ward to next video

[@autoknight747]

It was the gear selector motor. All running great now. There’s a video !

[@user-pd2yk9vk6h]

Hi just had this happen to me everything was fine undid battery to replace few things 3bars when plugged back in trying everything but I knew nothing was broke or needed replace few things I noticed was the beep sound not happening this is linked to abs and track and the dash relay so I looked in to fuses in book said checked a few all good so I decided to check all and #18 was blown this control esp dash and few other things long story short change it and turned key and the beep noise started hearing that I pressed brake pedal 3 to 5 times and everything came back 😀

[@autoknight747]

That’s interesting to note. I wonder why that fuse blew? A lot depends on fuse 18!

[@unknownunknown8707]

What area do you live? I have a full Mercedes MB star system you could use. I bought it recently for actuator relearns etc. deep dive faults. Your 3 dash may be fixed with a relearn. Brake switch can also cause chaos.

[@autoknight747]

Thank you, that’s a very kind offer. I’m in South East England.

[@unknownunknown8707]

@@autoknight747 Anywhere near Watford?

[@autoknight747]

@@unknownunknown8707 sadly not, quite a distance.

[@user-pd2yk9vk6h]

I have same issue

[@autoknight747]

Check out my shorts videos on my findings. A good first thing is to also ensure the engine earth is good. I removed the earth strap at the engine and lightly sanded the surfaces before refitting. Held by a Torx bolt which is easiest to access from under rear right of engine.

[@victoradorno6047]

Have you checked the brake switch

[@autoknight747]

Replaced a while ago and made a video on that. Brake lights fully functional now!

[@victoradorno6047]

I asked you that because i saw a video where was a similar problem and was fixed with the brake swith. Hope it can help.