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smartcar is losing sense of what gear it's in.

46K views 71 replies 18 participants last post by  mightyss 
#1 ·
I've got a 2008 451 pure, 47000 miles. The car tends to lose it's sense of what gear it's in at various times (sometimes when at a stoplight, sometimes while moving through the gears on local streets, and once while cruising on the interstate). Then it gets all confused and various warnings appear: the check engine light appears and flashes, the double wrenches appear and flash, the big D (Drive) switches from solid to flashing, and the yellow exclamation triangle appears and flashes. It also then goes to and stays in 5th gear. After slowly moving to a safe place, I turn off the engine and the 3 horiz bars show. In order to get the car to start, I then go through the sequence of waiting about 30 secs to a minute, then put foot on brake pedal, turn ignition key to position 1, then shifting from P to R, N, D and back for the electronics to figure out where it is. Once I see the D re-appear, I can go to P and start the car. The wrenches disappear, sometimes the check engine and the safety exclamation lights disappear too!

This has now happened more than 6 times in the past 2 weeks. Last Sunday (6 days ago) I removed, cleaned and adjusted the clutch actuator, using the advise found in threads on this forum. I found the insides of the actuator with powdery, dried out black lubricant, and relubed with white lithium grease. I reattached the actuator to the spec sheets recommendation of 3 gradation lines displacement from abutment towards the bell housing. I don't believe the actuator is the cause of the problem, since the shifting confusion has occurred before and since the cleaning. The worst was yesterday, it ran amok 4 times in 4 miles before I could get it home

Any ideas would be appreciated. Today I put a help request to the local smart center using their web-link in smartusa, but I have never dealt with the service center, having bought this car used.
They phoned me almost immediately, wanted to know if I wanted to set up an appointment.
Being on a very, very limited budget, I cannot blithely setup a service appt and hope for the best to a Mercedes Benz service dealership. I need some reassurances before handing over the keys. I asked to speak to a service tech, was told all were busy so my message would be passed on to them and one would get back to me.

So has anyone here had a similar problem with their car, and how did you fix it?
 
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#5 ·
I replaced the battery, cleaned up all connections there and found to my dismay the car is even worse now than before - it errors out with the 3 bars of death going from 1st to 2nd as soon as I drive it. The new battery is fine, 13.78 volts (the smart orig battery was probably fine too, at 12.6v, but I replaced it anyhow)
 
#6 ·
A good battery wont make the problem worse, but a wiggled loose connection would. I'd still say bad ground since it got worse by moving the wires around down there. See if anything attaching to the chassis is loose(loosen and retighten too while youre in there, 10mm socket). If not, consider replacing the main ground lead with a generic 2 or 4 gauge 10" ground cable from autozone.
 
#10 ·
was the shifter motor oil from the transmission went inside the carbons try to pull the 2 covers of the shifter motor and clean first with gasoline and then another cleaner like break cleaner.

Uhh, you lost me there, rubyg. Could you explain what you mean? Meanwhile I'll poke around down there.

Also I went through every ground bolt, fuse, and connections I could find around the battery. There is no sign of corrosion, every connector was tight, no resistance found by wiggling the wires all over. I doubt the issue is in the wires around the battery.
 
#9 ·
I am planning to attack this possible electrical shorting issue tomorrow. Does anyone here know of any similar threads on this forum where this problem has been discovered and hopefully resolved? I HAVE noticed the headlights wavered slightly in intensity from time to time, but always seemed so slight to might be just my imagination, but now...hmmmm.
 
#11 ·
The shifter motor is located on top of the transmission is actually 2 motors in one with some hall sensors if you take the air intake from the air filter boc to the engine you can have access to the motor it has 2 connectors.
You can remove the left and right cover of the shifter motor and clean with a brush and some cleaner,carfully inside each cover there is a magnet dont drop them they can crack.
In my case I paid $1000 for a new motor at the dealer, I took the old cleaned and compaired with some friernd spare and check it with a power supply in both direcctions of rotation and perform the amps comparation and they were the same.
A month later saw the service manager in a shopping center and I ask him why he didnt clean this part the response was we at the dealer we only change parts we dont try to clean o fix nothing...
 
#13 ·
The shifter motor is located on top of the transmission is actually 2 motors in one with some hall sensors if you take the air intake from the air filter boc to the engine you can have access to the motor it has 2 connectors.
You can remove the left and right cover of the shifter motor and clean with a brush and some cleaner,carfully inside each cover there is a magnet dont drop them they can crack.
In my case I paid $1000 for a new motor at the dealer, I took the old cleaned and compaired with some friernd spare and check it with a power supply in both direcctions of rotation and perform the amps comparation and they were the same.
A month later saw the service manager in a shopping center and I ask him why he didnt clean this part the response was we at the dealer we only change parts we dont try to clean o fix nothing...


GFY
 
#12 ·
Problem is fixed, thankyou all for the advice.

Finally had time to install a new neg terminal post and heavier gauge cable to ground. Also got some dielectric grease, and went back carefully re-cleaned and greased all positive and negative connections within the battery compartment, as well as the blades to the 50 amp fuse found near the positive post connection.

Total cost: $10.61. Drove it this afternoon and evening for about 20-30 miles without a hiccup in the shifting.

WOW! :thanks_smile::thanks_smile::thanks_smile: to all for the GREAT ADVICE!

Amazing how sensitive the electronics must be to have such a simple fix for what appeared to be a major FAIL in the vehicle. I hope the newer models have addressed this issue.
 
#14 ·
Whoa STOP! Problem is NOT fixed, need more advice.

The shifting issue has returned. For the last two weeks the car would lose sense of what gear it's in about once every other day, on the the return trip of a 44 mile commute. No biggie, I'd just pull over and park, turn off engine and go thru the restart routine as mentioned previously.

Today it happened 3 times in a 4 miles. I was on secondary streets. Once I was finally able to get up and running smoothly, I stopped at a Autozone, the code is P0707:Transmission Range Sensor Circuit Low Input

Could this be one of the hall sensors in the shifter motor that rubyg wrote about?

At one of the failures, I noticed I had a choice of 2nd or 4th gear when in manual mode. The other time it was 5th gear only.
 
#16 ·
Removing the air-filter-to-engine plastic pipe assembly (ugh, that lower right screw was a ***** to remove!) exposes the shifter motor on top of the tranny. Noted the shifter motor breather port with cap has appeared to leak oil over time. (Maybe the tranny fluid has been expanding too much or foaming?)

After cleaning the exterior a bit, noticed the multiple screws holding the motor covers in place. Will probably attempt to open them after cleaning the exterior more and tucking shop rags under the unit to catch the internal magnets (if they fall) rubyg has cautioned about.

smarticus, did you have the same code too?
 
#17 ·
My Ultraguage is not showing any code. Odd I think that it wouldn't. My dash shows the double wrenches from hell -2. I first will service and reset the computer and see if that helps. Then I will start looking for loose connections and fittings.
Surely the magnets are not just floating around loose under the covers,...it seems like they would be attached some way. ( Maybe that's the problem, bad glue ) Mine has done this about 6 times in the past week or two, including yesterday afternoon and just about 20 minutes ago. It's really getting old, fast. I just put new wheels, tires and a nice Carlsson exhaust on and it would be nice to be able to enjoy them. The problem was there before either of the changes / improvements were installed, so they aren't the problem.
I will post any findings.
 
#19 ·
As of yesterday I have finished cleaning out the electric transmission motors and replaced the gearbox oil with Redline MT90. The 2 electric motors were infused with a mixture of oil and carbon, about an ounce of the gunk was flushed out of the right side motor. After flushing the motors with electrical parts cleaner, I lightly greased the motor bearings with dielectric grease in hopes of creating a barrier against further tranny oil invasion (or at least slowing it down). Added the Redline before replacing the motors, just poured it in through the mounting hole until it came out the upper fill hole. I took pictures of everything I could think of during the process. I also cleaned the connectors and lightly greased the seals to both motors upon reassembly. Looking up at the motors from underneath the car, I realized these cable connectors are very much exposed to the elements. Also saw that the tranny oil had seeped over time enough to lightly gunk up the drive shafts to the rear wheels, so I cleaned that off with brake cleaner as well. The old tranny oil was a dirty chocolate brown, with gold highlights when swirled, showing the brass wear, I guess. Total cost: $76.70. So far I have driven the car just over 100 miles with no check engine light, other than one showing when I first started it up. That was expected, since I had disconnected the battery and the computer had to find just where everything was. Also had the ESP warning exclamation show until I turned the car off and restarted, also expected. Keeping my fingers crossed at this point...
 
#25 ·
As of yesterday I have finished cleaning out the electric transmission motors and replaced the gearbox oil with Redline MT90. The 2 electric motors were infused with a mixture of oil and carbon, about an ounce of the gunk was flushed out of the right side motor. After flushing the motors with electrical parts cleaner, I lightly greased the motor bearings with dielectric grease in hopes of creating a barrier against further tranny oil invasion (or at least slowing it down). Added the Redline before replacing the motors, just poured it in through the mounting hole until it came out the upper fill hole. I took pictures of everything I could think of during the process. I also cleaned the connectors and lightly greased the seals to both motors upon reassembly. Looking up at the motors from underneath the car, I realized these cable connectors are very much exposed to the elements. Also saw that the tranny oil had seeped over time enough to lightly gunk up the drive shafts to the rear wheels, so I cleaned that off with brake cleaner as well. The old tranny oil was a dirty chocolate brown, with gold highlights when swirled, showing the brass wear, I guess. Total cost: $76.70. So far I have driven the car just over 100 miles with no check engine light, other than one showing when I first started it up. That was expected, since I had disconnected the battery and the computer had to find just where everything was. Also had the ESP warning exclamation show until I turned the car off and restarted, also expected. Keeping my fingers crossed at this point...

Please post pics so the entire community can see what you did !!!

Thanks for the update :D
 
#20 ·
Hey, I had the same problem. Sometimes it would shift before or not even shift when going up a hill. I had that problem until one day my smart just decided to jump 3rd gear all together. I turned off the car, turned it back on and the problem disapeared. Took it to the dealership and all they did was install the 2012 hardware. Problem was solved...
 
#22 ·
After 1 month of use and 1200+ miles later, I am happy to report I have not had any shifter problems, check engine lights or 3 bars of death. I believe cleaning the gunk out of the 2 shifter motors and sealing the bearings , as well as cleaning and sealing the connectors has made this issue go away for now. Upgrading the transmission fluid didn't hurt either.
 
#23 ·
Jebcidic
My Ultraguage has shown fault code 2802:
Transmission Range Sensor B Circuit Low Input
I have cleaned and lubed all connectors external to the trans., so I guess I will pull the shift motors and flush and clean them like you did. Any pointers or warnings before I start would be appreciated. You said you did photos, are you going to put them here on the forum? I will try to shoot some as I get into the job this weekend. Thanks for passing along the " how to" info.
 
#31 · (Edited)
Pictures at an Exhibition 01

Ok, first let me get this out of the way - my note, "all they did was install the 2012 hardware...???? - care to elaborate?" was for Toslow, at post #20.

Here's the picture of the transmission motors's vent with oil spewed debris on the exterior of the housing:
 
#71 ·
Pictures at an Exhibition 01

Ok, first let me get this out of the way - my note, "all they did was install the 2012 hardware...???? - care to elaborate?" was for Toslow, at post #20.

Here's the picture of the transmission motors's vent with oil spewed debris on the exterior of the housing:
62042

Pictures at an Exhibition 02

Next is a picture of both transmission motors before removal. This view is with the engine hatch off, I am standing behind the smart looking into the engine hatch with the air intake baffle off. (also be sure to seal the air intake into the engine to prevent any debris from getting into the carb/fuel injection ports.)

62043

Pictures at an Exhibition 03

Right side electric transmission removed. Remove both motors and the housing as one would be easier (4 screws) than this, but was exploring in small steps at this point.

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Pictures at an Exhibition 04

Dirty housing, gunk mix of transmission oil and carbon from motor brushes.
Also the 4 magnets are shown, and the rubber plug at the end of the motor housing can be removed by your fingers before you (carefully!) pull the housing off the motor. The magnets provide strong resistance as you pull it apart.

62045

Pictures at an Exhibition 05

Dirty motor - what I failed to photograph was the gunk that I just knocked into the garbage can - this is just the debris left behind! Really, easily a couple of ounces. The left side motor wasn't as bad, but still needed cleaning.

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Pictures at an Exhibition 06

Cleaned motor - I flushed the housing and motor with "CRC QD Electronic Cleaner" found at the auto-parts store. Also used this stuff for the wire connectors, both sides

62047

Pictures at an Exhibition 07

Geared end of electric motor - This is where I suspect the oil is getting in. I used a cotton swab and applied a thin layer of automotive grease around the gear on the bearing seal in an attempt to slow the progress of any future oil from seeping through.

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Pictures at an Exhibition 08

Electric motor ready for re-assembly. Note rubber o-ring in place on housing and the 4 screws with Permatex threadlocker (I used medium strength blue) on it.

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Pictures at an Exhibition 09

Gasket material on housing: I used "Permatex Ultra Black maximun oil resistance RTW silicone gasket maker", available at auto-parts store in 0.5 oz tube

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Pictures at an Exhibition 10

This the opening in the manual transmission after removal of the electric motors assembly. I kept it covered with kitchen plastic wrap to keep the crap out as I cleaned around it. Drain the oil and open the overflow plug too from below. Once you are ready to reassembly use this opening to simply pour the new transmission fluid in, until it flows out the overflow port. I used Red Line Synthetic MT-90 75W90 GL-4 (Amazon, couldn't find it locally). I am hoping this will prove to be a better fluid than what was in it before, it could be that I had (I bought this car used) Penske's crap in there (see elsewhere in the forum on how they approved their GL-5 junk for this tranny). Maybe why this failure happened.

I used the threadlocker on the bolts holding this together too. I also noticed none of the bolts were difficult to unscrew - i.e. they were not highly torqued like most engine parts in other cars are. I also carefully lightly lubed with a di-electric grease the rubber bushings on the electrical connectors after cleaning them with the spray cleaner, to help seal out any rain & snow spray. (Note how the connectors are exposed to the road below!)

This completes my DIY pictorial project of my electric transmission cleaning procedure. Sorry about the delay, I wanted to be sure the problem was resolved for good.

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#32 ·
Pictures at an Exhibition 02

Next is a picture of both transmission motors before removal. This view is with the engine hatch off, I am standing behind the smart looking into the engine hatch with the air intake baffle off. (also be sure to seal the air intake into the engine to prevent any debris from getting into the carb/fuel injection ports.)

 
#35 ·
Pictures at an Exhibition 04

Dirty housing, gunk mix of transmission oil and carbon from motor brushes.
Also the 4 magnets are shown, and the rubber plug at the end of the motor housing can be removed by your fingers before you (carefully!) pull the housing off the motor. The magnets provide strong resistance as you pull it apart.

 
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