[Jaimiew/08passioncabrio]

I will do my best to explain this issue in its entirety

I would also like to add that I have done not just hours but DAYS of research reading every and any post I can come across. both when the issue first occurred (last summer) and now as I revisit the problem

mechanical knowledge level: moderate
I have had a few cars by now and complete all work myself (brake lines, brake parts, fuel line and parts, suspension, no starts, sensors, etc you get the gist)
mostly I stick to GM Jeep and my current truck a 1985 F350 dually

the smart:
2008 Smart Passion Cabriolet 451
purchased about 9 months before the issue occurred
drove hard as a daily commuter into NYC - 80 miles a day for about 6 months - with no issues at all
issue presented itself after the commute was no longer necessary and car was being used as a grocery store commuter
occasionally ABS light would come on but left
TPM sensor light always on-previous owner gave me a folder with all work ever done on smart since ownership in VA
sensors were replaced but were provided by customer
clutch actuator replaced about 1,000 miles before purchase so she was having the issue as well perhaps

the problem:
driving down the road after over 2 hours on a road trip
going about 30 mph when the car started to violently jerk so I immediately pulled over, foot on brake, shift into park, turned off
attempted to start and drive and would start easily but no gears and three lines
removed and replaced as many connecters as could be reached, removed negative battery cable, transmission reteach all on the side of the road
towed home
messed with clutch actuator by removing and greasing
experienced three lines still
purchased after market amazon actuator for cheap and lubricated before installing and reteach
no more three lines and would drive
BUT........
after maybe ten minutes of driving or less when I stopped at a red light it DROPPED OUT OF GEAR or so it felt
a very strange sensation I might add
back to only Park and Neutral
so I hopped underneath, loosened actuator bolts, moved slightly, retightened
good for another five minutes until the same problem
so finally I gave in and towed to nearest SMART dealership 1 hr away
not interested in throwing parts at it as I can do that myself!
there is an electrical fault somewhere and hoped qualified mechanics with a lift would find
their best guess is a new clutch pack and bearing but im not buying it as I am not convinced that is the issue - also quoted 2,800 which is a rip off
it drove just fine before this strange jamb up
little jolting in the shifting but nothing more than any other smart
they did star and sent back with my actuator in (grease hand prints all over cream interior, hood not attached correctly and so flailing in the air on the back of the tow vehicle, and several plastic plastic pieces floating around of which im not sure where they belong-----this is why if you want something done right do it yourself)
currently starts just fine and only Park and neutral

steps I've taken:
replaced and lubricated actuator
battery disconnect on multiple occasions
reteach on multiple occasions
STAR reteach
possible throwout bearing wear
visual inspection of many wires especially near the end of the casing and they are in quite good shape actually but im almost positive one is chafed somewhere
removed and tested TRANSMISSION TCM - good
checked ALL fuses and good

suspect list:
gear shift Motors/wiring
chafed wire somewhere
possible speed sensor issue?
abs timing at the wheel?

questions:
where is the actual CLUTCH ACTUATOR SENSOR? with pictures please!!
in a truly manual car it is near the pedal

 

[chetb]

where is the actual CLUTCH ACTUATOR SENSOR? with pictures please!!
in a truly manual car it is near the pedal

There's some discussion of the clutch actuator sensors in this thread -> Clutch actuator disected

I couldn't find any pictures though. The prevailing theory seems to be that there are sensors that count the rotation angle and direction in the clutch actuator. It seems obvious such sensors are required to move the rod the correct amount to feather the clutch when switching gears. There's more information about similar sensors that are in the gearbox motor here -> 451 Gear Change Motor Testing | Evilution

Sorry if this is not of much help.

 

[Jaimiew/08passioncabrio]

There's some discussion of the clutch actuator sensors in this thread -> Clutch actuator disected

I couldn't find any pictures though. The prevailing theory seems to be that there are sensors that count the rotation angle and direction in the clutch actuator. It seems obvious such sensors are required to move the rod the correct amount to feather the clutch when switching gears. There's more information about similar sensors that are in the gearbox motor here -> 451 Gear Change Motor Testing | Evilution

Sorry if this is not of much help.

I have completely dissected the unit myself. it has to be an additional component located elsewhere or built into something else. lots of research and even that forum show no true answer of where "clutch actuator open circuit A" could be

 

[chetb]

I have completely dissected the unit myself. it has to be an additional component located elsewhere or built into something else. lots of research and even that forum show no true answer of where "clutch actuator open circuit A" could be

Have you opened the clutch actuator motor casing and looked in the circled area close to the connector?

There's a couple of pics of the sensors in the gear motor in two of the last three pictures in this post -> Shift motor teardown (and maybe someday, rebuild)

They're not clear though. I'd asked in that thread if anyone has better pics, but I was told this:

There is nothing to see. They are surface mount Hall effect sensors, little black cuboids soldered to a PCB. I have replaced faulty ones with 44E and they work fine.

A simple test might be for you to do what the evilution does in 451 Gear Change Motor Testing | Evilution . Connect 5v to the sensor+ pin, ground to sensor- pin, and connect the two position sensor pins to an oscilloscope. Turn the motor shaft by hand in both directions and see if you can get the outputs similar to that what's shown in the evilution link. This post should be useful to identify the pins:

1- stepper sensor - (Brown/Grey)
2- sensor position 1 (Blue/Yellow)
3- actuator motor + (Red/Green)
4- sensor position 2 (Grey/Violet)
5- stepper sensor + (White/Yellow)
6- actuator motor - (Violet/White)

Is it OK if I borrow some of these pictures for later use? (full credit to you obviously).

Looks like a rusted pivot shaft could be another factor of failure of these units and it could be beneficial to fire some penetrating lube into them every year just to keep it free moving.

Thanks to Chief for the heads-up email. I would have replied but although you sent it twice, you got your email address wrong both times lol.

 

[Jaimiew/08passioncabrio]

Have you opened the clutch actuator motor casing and looked in the circled area close to the connector?

View attachment 69668

There's a couple of pics of the sensors in the gear motor in two of the last three pictures in this post -> Shift motor teardown (and maybe someday, rebuild)

They're not clear though. I'd asked in that thread if anyone has better pics, but I was told this:



A simple test might be for you to do what the evilution does in 451 Gear Change Motor Testing | Evilution . Connect 5v to the sensor+ pin, ground to sensor- pin, and connect the two position sensor pins to an oscilloscope. Turn the motor shaft by hand in both directions and see if you can get the outputs similar to that what's shown in the evilution link. This post should be useful to identify the pins:

Having now had three separate clutch actuators in and the problem persisting (Smart dealer also placed a temporary new Sachs to confirm) I do no think that process will be helpful. if anything it would potentially be the clip/wires upstream from the actuator itself and matching those pins. also, is that process not for the Gear change motors? those are different from the pictured actuator. and yes, I am starting to suspect it is my gear change motors but have not gotten to testing or removing it yet.


\/ I removed the cap to try and peak inside. overall it looks awful and is next on my suspect list though I have a strong hunch it is a faulty wire somewhere.

thanks for the replies

 

[jetfuel]

…just from the looks of the outside I’ll bet the inside is worst…

jetfuel…LUK

 

[chetb]

Having now had three separate clutch actuators in and the problem persisting (Smart dealer also placed a temporary new Sachs to confirm) I do no think that process will be helpful. if anything it would potentially be the clip/wires upstream from the actuator itself and matching those pins. also, is that process not for the Gear change motors? those are different from the pictured actuator. and yes, I am starting to suspect it is my gear change motors but have not gotten to testing or removing it yet.

yes, the evilution link is for the gear change motors, but i'm guessing the actuator motor's pins and sensors are similar to them. All three connectors (2 for gear change motors, one for actuator motor) have 6 pins each - 2 for turning the motors, 2 for powering the sensors, and 2 sensor outputs. Since you're sure your actuator is good, you're right that if you do this test you should clip the corresponding pins on the TCM connector (pins 20 and 28 according to 451 Gearbox Controller Pin Out | Evilution )

Since both your error codes are about improper voltages from clutch actuator, and you trust your actuator, it might be worth it to test the harness. Did you test the harness by applying a voltage on the pins at the actuator end of the harness and checking the voltage values at the TCM end of the harness?

 

[Jaimiew/08passioncabrio]

yes, the evilution link is for the gear change motors, but i'm guessing the actuator motor's pins and sensors are similar to them. All three connectors (2 for gear change motors, one for actuator motor) have 6 pins each - 2 for turning the motors, 2 for powering the sensors, and 2 sensor outputs. Since you're sure your actuator is good, you're right that if you do this test you should clip the corresponding pins on the TCM connector (pins 20 and 28 according to 451 Gearbox Controller Pin Out | Evilution )

Since both your error codes are about improper voltages from clutch actuator, and you trust your actuator, it might be worth it to test the harness. Did you test the harness by applying a voltage on the pins at the actuator end of the harness and checking the voltage values at the TCM end of the harness?

Great, thank you for that pin out link. so, the only information Im missing from that table is how much voltage each pinout should register on my multimeter... I will certainly be checking the TCM input connectors again as all I did the first time was check the unit for continuity. electric is my least favorite type of diagnosis though it perhaps feels the most rewarding when its solved.

 

[chetb]

Great, thank you for that pin out link. so, the only information Im missing from that table is how much voltage each pinout should register on my multimeter... I will certainly be checking the TCM input connectors again as all I did the first time was check the unit for continuity. electric is my least favorite type of diagnosis though it perhaps feels the most rewarding when its solved.

just to clarify, what do you mean by "check the unit for continuity" ? how exactly did you do that without having the pin out info previously?

 

[chetb]

I know it's probably not relevant to you anymore, but here's a video that shows the outputs of the hall effect sensors on a smart roadster actuator at 1:03 . the fortwo actuator motor is likely pretty similar.

 

[Jaimiew/08passioncabrio]

just to clarify, what do you mean by "check the unit for continuity" ? how exactly did you do that without having the pin out info previously?

I did not have the complete list but I knew the two needed for continuity from some light research

 

[Jaimiew/08passioncabrio]

yes, the evilution link is for the gear change motors, but i'm guessing the actuator motor's pins and sensors are similar to them. All three connectors (2 for gear change motors, one for actuator motor) have 6 pins each - 2 for turning the motors, 2 for powering the sensors, and 2 sensor outputs. Since you're sure your actuator is good, you're right that if you do this test you should clip the corresponding pins on the TCM connector (pins 20 and 28 according to 451 Gearbox Controller Pin Out | Evilution )

Since both your error codes are about improper voltages from clutch actuator, and you trust your actuator, it might be worth it to test the harness. Did you test the harness by applying a voltage on the pins at the actuator end of the harness and checking the voltage values at the TCM end of the harness?

so rereading this post. are you saying to disconnect the connector at the TCU and supply voltage while also disconnecting the connector at the actuator and checking for the supplied voltage? essentially testing the wires. seams like a great step and something I should do to any connector related to the transmission system.

so far today was getting the smart into my tiny garage and up on four jack stands. the next clear warm day I will be attacking this problem.

 

[chetb]

so rereading this post. are you saying to disconnect the connector at the TCU and supply voltage while also disconnecting the connector at the actuator and checking for the supplied voltage? essentially testing the wires. seams like a great step and something I should do to any connector related to the transmission system.

so far today was getting the smart into my tiny garage and up on four jack stands. the next clear warm day I will be attacking this problem.

yes. all i'm suggesting is to test the harness before you dig deeper. supply voltage at one end and check at the other end. i'd recommend doing it for all 6 clutch actuator wires.

i'm still a little confused by what you meant by "check the unit for continuity". How exactly did you do it (i'm hoping to learn something from your answer, i'm new to all this as well)?

 

[Jaimiew/08passioncabrio]

this was about midsummer last year so I am foggy on the details. I found a YouTube video of someone using continuity (beep sound on multimeter) with their TCU unplugged to just check that power was entering the unit and completing a circuit (power supplied via the multimeter). I could be mistaking the terminology.

btw, this is an amazing video explaining the HALL EFFECT SENSORS.. only downside is it is in Spanish.
Hall Sensors

 

[Matrix11229]

purchased after market amazon actuator for cheap and lubricated before installing and reteach
no more three lines and would drive
BUT........
after maybe ten minutes of driving or less when I stopped at a red light it DROPPED OUT OF GEAR or so it felt
a very strange sensation I might add
back to only Park and Neutral
so I hopped underneath, loosened actuator bolts, moved slightly, retightened
good for another five minutes until the same problem

they did star and sent back with my actuator in
currently starts just fine and only Park and neutral

steps I've taken:
replaced and lubricated actuator
battery disconnect on multiple occasions
reteach on multiple occasions
STAR reteach
possible throwout bearing wear
visual inspection of many wires especially near the end of the casing and they are in quite good shape actually but im almost positive one is chafed somewhere
removed and tested TRANSMISSION TCM - good
checked ALL fuses and good

suspect list:
gear shift Motors/wiring
chafed wire somewhere
possible speed sensor issue?
abs timing at the wheel?

questions:
where is the actual CLUTCH ACTUATOR SENSOR? with pictures please!!
in a truly manual car it is near the pedal

What helped in my case was reset with a good scanner at my friend's shop and installing oem clutch actuator. My cheap scanner that resets codes didn't help.
Also, it might be a good idea to to check if there's no water/moisture at the clutch actuator harness connector inside the cabin.
The harness enters the cabin through a wall behind driver's seat and goes precisely under driver's seat where it connects into a module with a latch connector.
I just wanted to make sure there's no damage to harness or poor connection.
I removed driver's seat screws, lifted the seat a bit towards passenger side and lifted the carpet to expose the module and actuator connector under the seat. Disconnected and reconnected . The area was dry but I did find some moisture under the carpet closer to pedals. Wouldn't hurt to check if you have water pooling in there. If not , then it's a matter of resetting with a good scanner while engine is on and having proper actuator adjustment (mine has 8 notches visible).

 

[Jaimiew/08passioncabrio]

What helped in my case was reset with a good scanner at my friend's shop and installing oem clutch actuator. My cheap scanner that resets codes didn't help.
Also, it might be a good idea to to check if there's no water/moisture at the clutch actuator harness connector inside the cabin.
The harness enters the cabin through a wall behind driver's seat and goes precisely under driver's seat where it connects into a module with a latch connector.
I just wanted to make sure there's no damage to harness or poor connection.
I removed driver's seat screws, lifted the seat a bit towards passenger side and lifted the carpet to expose the module and actuator connector under the seat. Disconnected and reconnected . The area was dry but I did find some moisture under the carpet closer to pedals. Wouldn't hurt to check if you have water pooling in there. If not , then it's a matter of resetting with a good scanner while engine is on and having proper actuator adjustment (mine has 8 notches visible).

I have already done that when I removed the TCU/TCM and did partial test.
Mercedes performed said scanner rest/tests.

 

[Jaimiew/08passioncabrio]

Everything apart and in pretty good shape actually. Back in temporarily (will be replacing gear oil via this port and gasket as well as fresh bolts) and problem is unaltered.
new battery.
time for what I've been avoiding.. all of the connectors/pins..

all gears showing up (on dash cluster anyways) when key in ON position
P,N show when engine on and R/D are blank

no additional codes on basic scanner and there were no additional when Mercedes used their STAR.. just P0805.... no more P0900

 

[chetb]

If you have the gear change motor open again, can you please take clearer pictures of the hall effect sensors and the PCB they're mounted on?

 

[Matrix11229]

no additional codes on basic scanner and there were no additional when Mercedes used their STAR.. just P0805.... no more P0900

Did mb dealership reset your ECU with new actuator installed?

Did you check for water under driver's seat and clutch actuator harness for damage?

 

[Jaimiew/08passioncabrio]

Did mb dealership reset your ECU with new actuator installed?

Did you check for water under driver's seat and clutch actuator harness for damage?

when under the driver seat to check TCM yes, I looked. that's where the TCM s located.


please help me figure out which sensor this is without having to remove and read part id number.

located just above the clutch actuator

share the wiring loom as the clutch actuator

two green wires