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I purchased a used 2012 Cabriolet last month to tow behind our Winnebago View which I had bought upon retiring last year. The car has only 25,000 miles and my wife and I are really looking forward to seeing the country with this combination.

Before having the car outfitted for towing I spent a lot of time here reading posts to determine what set up I wanted to use for towing and brakes. I ended up having a Blue Ox adapter and tow bar and a Roadmaster Invisibrake installed. The work was completed last Monday by a local RV specialist.

After towing the car back home from installing the brake system and disconnecting it from the RV I'm having a serious problem with the transmission shifting properly. On some gear changes the engine power will cut out and the transmission will not select the next gear. It happens in both D and manual mode, and even on occasion the engine will seem to cut out and the vehicle starts losing speed when cruising along at 50 mph. Though there is no check engine light I did a check with my bluetooth OBD2 device and found that there is a P0949 code: Adaptive Learning Not Done. Through all of this I have never seen the 3 bars on the display to show that it actually ever tried to learn anything and I don't see any way to actually trigger the learning myself.

Does anybody have any thoughts on what may be happening here? When installing the brake system they had the entire pan off the bottom of the car so they could access the vacuum lines and run wiring and a secondary brake light switch that is required for the Invisibrake. (I did install a battery switch on the positive terminal which is also a Roadmaster requirement for the Invisibrake). Is there a particular connector which could have been knocked loose while they were playing with the vacuum, brake switch or brake pedal area? I plan to take it back to the installer tomorrow so he can look into loose connectors but if he doesn't find anything obvious I'm not too certain he could really diagnose it further.

I looked through all the posts I could find about adaptive learning at this forum but I haven't found anything that would lead me to a solution. Is there a way for me to trigger the learn process and see it through? I've tried cycling the battery disconnect switch but restoring power always gets me back to a P or an N in the display.

Thanks for any help you can offer,
Gary
2012 Passion Cab
 

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Yes, I've done that several times with no luck. I also tried another procedure I had found on line that involved putting the key in position I and manually moving the lever through P>R>N>D>+>-D>N>R>P, then turning the key off and restarting the engine.

After doing those things the OBD2 reader still shows the P0949 code and the problem still exists on a test drive.

Gary
 

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shift into each gear and wait for the shift motors to get done clunking around before moving to the next gear. If you shift to fast during the learn in , it won't register.
 

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I think we got the transmission figured out. You can force the three bar learn sequence by disconnecting the battery while the instrument panel is still illuminated. But that in itself was not sufficient to correct the situation as the shift problem recurred during a test drive. Trying the shift position sequence by itself next did not help. Only by following the three bar learn sequence immediately with the P>R>N>D>+>->D>N>R>P procedure do we seem to have corrected the shifting. Time will tell if the transmission adapts (or I adapt to it I suppose).

But now I seem to have a problem with the ESP light staying on. I stopped by an independent German car mechanic to shut off the air bag light (which was illuminated because the battery had been turned on when the seats were out of the car) and he noted that the ESP code was due to an "implausible brake light condition" according to his device. He reset the code but it reappeared within a mile of leaving the shop. The Invisibrake system required that a secondary brake switch be installed (since the positive battery terminal is switched with this system), which was done by my RV guy. I called Roadmaster about the problem and they said they have seen this before when the secondary switch was not properly adjusted. Essentially, the secondary switch can interfere with the proper return of the brake actuation rod, triggering a a fault which shuts down the ESP and illuminates its light in the dash. (If the ESP is inactive the car does not allow setting of the cruise control among other things).

Anyway, I took a test drive and checked the brake lights several times, always finding them off, but when I pulled into my driveway I put it in Park, opened the door quickly and found that the brake lights did stay on for about 5 seconds. This seems to confirm the Roadmaster diagnosis. I did have my wife actuate the brake several times and could not get it to stick again but even once is enough to suggest the problem.

I have an appointment Monday to get the switch adjusted and will post again if that does not work. I thought this information may be useful for anybody who decides to install an Invisibrake on their Smart Car. Thanks to you who commented and to SCoA for providing this forum.

Is there a way to move this information from the New Members section to the towing forums?

Gary
2012 Passion Cab
 

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Discussion Starter #7
Thanks Slivers! I printed this to take to my RV guy. Is this instruction drawn specifically for the Invisibrake secondary switch or the existing one in the Smart Car?

By the way, this morning I am again experiencing some speed loss in the car when shifting. It totally missed a 3-4 upshift and even after I manually got it in 4th I could feel the power drop out for a bit while the car lost speed. I'm wondering if I'm having a clutch actuator problem and plan on doing the clutch clean and lube procedure I found at this forum. I also still keep getting the ESP light and I'm wondering if that plays in to the shifting and clutch problems.
 

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I always cross my fingers after towing that the trans will "re-learn" when I turn on the battery cut off switch. So far never a problem. However, most of the time the "check engine" light comes on and stays on. Yep, my OBDII revealed the same code you are getting. After 3 or 4 restarts though, it clears. No operational problems though.
Regarding the ESP light. It has come on twice recently but not towing. The owner's manual says to try turning off the engine and re-starting to clear it. That has worked both times. Coincidentally, one rear tire was 7lbs low. That may have triggered the ESP. I discovered and corrected the pressure after the second occurrence.
If your Smart was learning and shifting fine until the invisibrake install perhaps they caused a vacuum line leak or a poor E connection.. Sure hope it gets sorted out for you.
We chose not to install an auxiliary brake system after some driving tests behind the MoHo. Fortunately, the Ford MoHo brakes have proven more than adequate even on punishing steep downgrades from 10,000 feet.
 

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Discussion Starter #9
I have more information to add about the Roadmaster Invisibrake installation and the problems I've been having on my 2012 Passion Cab.

I had the car back to the installer Monday and he adjusted the secondary brake switch which Roadmaster says is required due to the need for the Smart to have the battery disconnected. Although everything looked good when I left I quickly had another ESP light and loss of cruise control function. On the drive home I again had the shifting problems and periodic loss of power so I stopped at a local Mercedes technician and made plans to stop back today.

The technician found an "implausible" brake operation code with his scanner and put the car on a lift. It turns out that the installation of the secondary brake switch for the Invisibrake required the removal of the Smart's primary brake switch since a hole needed to be drilled directly above it in the same bracket for the secondary switch. While the Roadmaster instructions for the switch include its adjustment they mention nothing about adjusting the primary switch after putting it back in.

It turns out that this switch has an internal adjusting feature and you cannot rely on just putting it back where it was. Before installing it in the quarter turn twist lock hole you need to pull the plunger all the way out so that the first stroke of the brake pedal can set the stroke of the switch internally. This is no simple switch as it actually has two circuits which need to provide signals in the correct order, first to the electronic stability program and then the brake lights. It does not even control things directly. You will note that the switch actually has four leads of a fairly small gauge wire which suggests it is only switching 5 volts not 12. I think this means that the switch only tells one of the computers what is going on and the computers then determine what to do (like ultimately turn on the brake lights). Effectively these things are constantly checking themselves and if something is not as the software expects it a fault will be logged and trouble will start.

The tech did the brake adjust step with the scanner connected and it confirm that the switching was in the correct order, so hopefully all is well. At least it is shifting and the cruise control is working again!
 

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Sounds like you found a competent mechanic who found the issue. The cruse control not working makes sense because the feature is always wired to the brake pedal switch or it's own switch to deactivate CC when the brakes are applied. Hopefully all will operate normally now for you. I wish our Smartie had CC. Happy towing
 

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After reading your horror story, i feel even better about how i did my smart for towing. I i stalled a battery cutoff switch under the dash so the battery is disconnected while towing (so in a rare case the computer won't wake up and do strange things like applying brakes, etc). I bought a set of magnetic WIRELESS lights and installed brackets i side the rear hatch glass. I do nit use a brsking system since the car is about 1850 lbs. i did not want to mess with anything electrical on the smart to give mercedes any excuse to void my warranty. No problems so far.
 

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Hopefully, his problems are solved now.
As you did, I installed a battery cut off under the dash. Yes, at 1800 or so pounds I find the MOHO Ford brakes have no problems at all. Never know it is back there. I don't know if it is necessary, but I do use a bungee on the steering wheel.
I like your idea of the wireless lights. Wish I had known about them. Like you, I stayed clear of the Smart wiring completely. I bought LED trailer lights and made some hidden/removable L brackets for them. The lights sit in front of the stock tail lights while towing. Brackets remove in about 5 seconds. No tools needed. I hid the wiring under the carpet all the way back.
I only wish the Roadmaster tow bar would disconnect from the Smartie cross bar as easily! Often have to knock out the large pins with a rubber hammer.
 

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We tried the bungee on the steering wheel and found it helped eat up the front tires. There was always some scrubbing even though we had it centered. Once we learned never to turn quickly one way and immediately the other way we never have problems with the wheel doing its lock to lock fubar. Good luck to you.
 

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Interesting. Does your Smart have electric or hydraulic steering? Ours is a '14 with electric. Perhaps I don't need the bungee at all. You are right about the scrubbing. Would be nice to avoid that by not having the bungee.
 

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Excellent! Thanks. I have yet to see a Brabus in person. Did see a special edition being towed by a fellow camper. It had yellow mirrors, a yellow stripe and yellow seat stitching. Cosmetic treatment only compared to your Brabus.

Jim
 

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Hey, george. I don't get on the site much any more, but i could guarantee anybody that your brabus is probably the cleanest and newest brabus in the country. Do you have 3,000 miles on it yet?
 
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