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Smart_guy

Nasty Electrical Problems

43 posts in this topic

Hello everyone, Im stumped. I have a 2006 Grandstyle at the shop right now that has issues when wet. To make it better, its intermittent, but only when wet. Took me 20km of driving today to get the fault. Here we go:The customer has been getting 3 bars and check engine light for input speed sensor, gear position sensor, rail pressure, EGR codes, shift drum codes, and when the rail pressure code comes it stalls and is a no start. Clear the code and all is good. First visit I saw gear position and input speed sensor codes so replaced them with OEM sensors. Customer drove for a couple weeks then bam!So I drove the car for 2 days back and forth to work no issues, wet the car by washing etc, no issues. Customer took the car, gone 10 minutes, calls me back.Checked for damage in th harness, couldn't find a problem, battery test is ok, no consistant problems, replaced both sensors with known good sensors. Drove for several weeks and 5 codes again, Input speed, gear position, gear drum, EGR, and rail pressure. I drove the car a ton with my scanner and found voltage spikes up to 16 volts for split seconds here and there, had to graph the data logger to see it. So I drop the engine down, pulled the entire engine harness. The alternator windings were corroded and green in several spots and its an aftermarket alternator. Right on, found a problem. So replace the alternator with OEM, took the whole harness out and removed all harness coverings and checked every wire for chaffing and corrosion. Not so much as a bad kink in a wire. Load tested every wire too. Actually used a test light and probe kit to test each wire. (I was extremely careful to not spread terminals) So I put the harness back in, new alternator in, start the hanging engine, no codes. Washed the hanging engine, retested, no codes. Drove the car for 30 kms, 3 bars! on take off it seems to be slipping out of gear. Checked the clutch actuator for adjustment, there is still room to adjust it, suggesting the clutch is still good. So clear codes and drive more since it is intermittent. Engine light comes on, rail pressure sensor, EGR, Input speed, and gear position.....WTF!!!! At this point Im really leaning on the EDG from the voltage spikes but really don't want to pull that trigger without being 100% on this. Please tell me Im a retard and have missed something obvious. Otherwise ANY helpful advice would be greatly appreciated. Oh did I mention that I am currently working on this for free. Thanks in advanceTroy

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If I plug one in and try swapping it with a known good one, do I just need the key that matches the SAM or do I need the EDG too? I have never attempted module swaps in a smart. If you are right theres a red lobster gift card coming your way :)

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I don't think you can swap a SAM....without recoding it to the VIN, but you could inspect it for water / terminal damage.

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If you remove the SAM you can inpect the connectors for burn marks. You can also open it up and inspect the pins integral relays and PCBs.

Also look for water trails in the area of the SAM. I don't think it's rare to find moisture damage and burnt leads/connectors. Maybe not actually common, but a number of reports here.

Happy hunting, cousin!

Bil :sun:

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Troy,Have you checked the main engine ground for corrosion?How about the ground above the intercooler?It wasn't clear, did you disconnect the 2 big connectors on the ECU? (Any corrosion)How about removing the ECU and cleaning its case and contact area on the subframe.As mentioned above check the SAM for damaged connectors, there is a posting by 2seatragtop about drilling drain holes in the SAM.Check the windshield seal for leaks.Hope this helps.Canman

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St. Patty's day SAM. Corroded internally. Once I got to the shop I looked near the vin on the dash and see a water trail through the dust! Pictures are coming soonTHANK YOU AGAIN CLUB SMART CAR, Bill, Mike and CANMAN

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I hope it's minor damage and can be repaired? Other wise I would like to know if you can order a replacement and what that might cost... maybe a couple hundred $$ ?Bil :sun:

Edited by bilgladstone

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I work at an auto wreckers and i know a few yards with smarts i can check a price if you like. Your profile doesn't say where you live (shipping?) :rolleyes:

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Wow it doesnt say where I am? Thats gotta be helpful for business :) Im in Winchester Ontario, 30 minutes south of Ottawa. I don't think you can put a used one in because they are married to each other with vin and whatnot. Correct me if Im wrong. Im trying to clean out the corrosion, doesn't appear to have rotted into the board, just touching contacts. The confusing part is why hitting puddles affected this with the SAM being inside the car......we will see :)

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I'm not certain about SAM mated to VIN or ECU. I have posted the question over on smartmaniacs and I will update when I hear back (usually someone knowledgeable answers within a few hours)Bil :sun:

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Confirmed. You cannot swap SAMs without programming the read-only memory. Likely not even a main dealership has the know-how to do this.

B :sun:

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Almost certainly the SAM is paired, a new one must be programmed by the true MB STAR. A used one may work if all the programming options are identical on the donor car. Same model, same options. I'm not certain if that's true, but for sure a new one must be programmed.

Troy: Have you seen my SAM repair thread? There may be some ideas in there applicable to your problem.

Edited by Alex

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I drilled drain holes, used electrical contact cleaner and a firm tooth brush to clean the board. I can't see if all the corrosion is gone as the relays are so low on the board, you will see tonight how far apart it was. The module is in the car and I have put 60kms on it today hitting every puddle I can.....got a cops attention too :) I appeared to be drunk or distracted going into the opposite lane to hit puddles on the left side :) All good though, he understood. Im driving it home tonight to really crank on some miles so the customer can confidently drive it.

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Are you going to wash his car after hitting all those puddles Troy :P

Edited by KurtMan

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Well done, sir! Did you manage to follow the drip trails and plug the source of water ingress so's to prevent future recurrence?Bil :sun:

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All the relays are just a couple mm off the board, I sprayed each one as best I could and let it dry for a long time so there is nothing trapped. Blew it off with a can of computer board cleaning. Used a good electrical contact cleaner.

post-5364-1359682954_thumb.jpg

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Used a firm bristled tooth brush to scrub in the recessed areas with contact cleaner then dried well. Put it all back together and so far so good 120kms later. I took pictures of the fuse locations at the start of the repair just in case. Really helps prevent scratching your head :)

post-5364-1359683117_thumb.jpg

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I once had a Bosch MOTRONIC ECU that had been totally drowned causing a total breakdown restored to perfect operation by Molyslip Combat spray.That car you're working on has a windshield leak.

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What type of contact cleaner did you use, Troy? Although I'm not having any of the symptoms, I'm thinking a preemptive pull-and-clean might not be a bad idea...Bil :sun:

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Molyslip Combat - thanks for the tip, Mike. Looks like it's readily available in Kelowna too!Bil :sun:

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