Done, fixed 3-bars, with new shifter module
It all starts with an out of the blue, 3-bars in the gear indicator location on the multifunction display
You can try the 45-sec reset, it may work. You can try the software upgrade to 2.0.2 (or 2.0.0), that may work.
If not, time to read the codes. U0103 and possibly U0404 are the ECU errors. Question now is it the (N15/5) Electronic Selector Lever Module Control Unit or the Transmission Clutch. In my case it was the module.
Next you need to locate the parts, first decision. Smart dealer for new part or ebay for salvaged part. Given new is $259 and used/salvaged is higher (w/key) for about 50% (wide range of prices), and given this appears by it failure to be a "wear" item, I'd suggest going with new. Old part A451 2600109 / new part from Dealer 451-260-04-09 w/o key tumbler, $259 list / $234 net plus tax. Swapping the key module wasn't that hard if you are handy. This is now referenced as the
N15/5 unit. This is the full unit under the console cover, minus the Transponder Coil and key tumbler, which you will reuse for old unit. ebay / salvage units seem to come with these parts, YMMV.
To start removal of old
N15/5 unit,
1. Remove the floor mounted cup holder (if optioned) by removing the T25 screw, front arm of cup n holder attached to bottom of dash support, on driver's side.
2. Lift handbrake, put car in Neutral (will need key ON to do this), lift screw cover at back of center console under handbrake arm. T20 screw, should be hand tight.
3. Straddle shift center console, grasp shift handle (BUT DO NOT SQUEEZE TRIGGER or it will break the tab), pull up on handle to "slide" it off shaft. Center console will not come up over shift handle when in place. It takes force and then comes lose in a snap, do not hit your face with your hand, so be careful try leaning out of the path of your hands.
4. Once off, press white pin in shifter shaft (now exposed) to put shifter back in Park. Turn off Key and remove key.
5. Lift up back of center console and slide/shift it forward to release front side of console from shift module, then lift the center console up and off the shifter module. Un plug position indicator cable from N15/5. (my new N15/5 cam with a new shift indicator display module that snaps into the center console case (replacing existing shift position indicator). Not sure why it came with it, but I used the new one since I paid for it :wink:
6. As you remove the console cover will expose an alarm module (ATA microwave sensor) near back of shifter under center console. Set it aside, do not smash it when later removing / installing drivers seat.
7. Note the red transport clip on the back of the unit ("parked" or snapped in it's holding are). Remove it and place it in the two passenger side holes in the center/middle of the N15/5 unit (while in Park). Big pin in the small hole, little pin in the large hole, it can only go in one way.
8. The N15/5 has a "bus" connection at the front of the unit that will need to be unplugged. The white plastic cartridge remains in the N15/5 and the cable disconnects from that. It is a tricky connector. It plugs in from the front and uses a 90 degree pivot motion on the retaining clip/cam/leaver to remove it. Fiddle with the light gray part of the plugs black plastic cap, it rotates up and the cam/leaver then pushes the plug out of the white plastic socket. Do not force it.
9. Locate the four (4) mounting screws (5 Spline Tx-Star T30) two on each side of the N15/5 unit where it meets the floor. The left/driver side are not easy to get to with seat and seat rails in place. You will have to pull back carpet to expose their heads. Removing the seat will make this a lot easier on both sides. I only needed to remove the drivers seat (leaning it back), but you may opt to remove both seats. You will need T45 and T50 for rear floor & front bracket seat hold down bolts and 17mm for seat belt retain bolt (only if removing seats from car). I was able to pull back carpet enough on the right / passenger seat with the seat in place to get access to both right side bolts (with passenger seat in place). I didn't have a 5-lobe T30 Security bit, but I found a set of channel lock pliers could clamp on the bolt head with enough grip to turn it a 1/4 turn, from there, they are finger grip lose enough to remove by hand the rest of the way. It is a tight fit on the right side with seat and carpet still in place, but can be done with patience (and a screwdriver handle placed between the carpet and the tunnel to keep the carpet far enough away from the tunnel to get your fingers in to turn and remove by hand/fingers). The 2 bolts on the left side will require removing the seat. I was able to undo the 4 seat boles (2 front and 2 rear), then the front floor seat bracket (2-bolts) and tilt the seat back far enough to access the N15/5 screws. I left the seat belt in place, tilted the back of the seat forward, then used the seat belt tension to hold back the seat when tilted back by placing the seat belt strap around the upper headrest area. Then 5-lode T30 or channel locks (like right side) to remove the 2 left side N15/5 screws same method as right side with carpet still in place. The Shift Module N15/5 should then lift up for remaining plug removal.
10. The N15/5 has three more connectors at the back:
- 10.1. One up top, driver side that you depress the tab facing the back of the car on the side of the connector and pull towards the drivers side. This is connected to the Transponder Coil that surrounds the key tumbler insert. The Transponder Coil just lifts off the key tumbler unit on the N15/5. So you could also leave it plugged in and just remove the Transponder Coil from the N15/5 key tumblers. Either or, I unplugged it that way the Transponder Coil was not in the way of accessing the remaining plugs as the wiring is tight between the seats and the N15/5. Having the Transponder Coil remain connected to the short wiring would have it resting in the same work area between the seats as the N15/5.
- 10.2. Second is a hidden one, tucked up under the rear of the module not really visible until you have the N15/5 lose from the floor and can look under it. It just unclips, but is a tight fit for big hands to get it to unclip. Accessed from drivers side of car with N15/5 tipped up (and cable still connected).
- 10.3. The third is the cable going into the lower bottom portion of the N15/5 that is release by 2-steps. I think this is some kind of parking lock for the manual transmission to get it to behave like a North America automatic. I guess engaging the parking break wasn't enough
Any way, there are 2 steps to unplugging the cable.
- 10.3.1. First on the passenger side there is a white plastic plug / clip that must be pulled out from the N15/5, this is a retaining clip/ring that goes round a collar on the cable. If you have the new N15/5, you can see this more clearly as to how it works.
- 10.3.22. Now look up under the N15/5 where the cable goes into the black plastic sleeve. Note the position of the red paint dots on the black plastic cam screw rim and the white cam screw itself. On the new N15/5 (hopefully) they are not aligned (this is the open cam sleeve position – cam screw red dot 90 degrees clockwise from cam rim red dot) and on the "installed" old N15/5 they are aligned (locked / closed cam sleeve position). To unlock turn the cam locking screw to align dots pulling it out by pulling the N15/5 towards the font of the car. It may "click" or "snap" but should not require much force. When reversing this to install the cable in the new N15/5, make sure the cable is fully extened out of the cable sleeve before inserting the exposed end of the cable back into the new N15/5, then locking the cam and inserting the cable sleeve clip.
11. With the N15/5 free from the car, take it to a well lit work area. You will need to transfer the key tumblers in the old N15/5 unit to the new part for your existing keys to work.
- 11.1. I was told by US MBenz parts guys that the dealer mechanics just break the case on the old N15/5 to remove the tumblers. I guess that is one way to do it. But if it turns out the N15/5 is not defective, well then you just ruined a good part.
- 11.2. There is a method to remove the tumblers without destroying the old N15/5 unit. That is what I did, it took some practice and patience, but can be done.
- 11.3. You will note that the black plastic N15/5 case is split down the middle in 2-halves, in part being held together by metal retaining clips. Remove the clip just under the key area and the one just behind the shifter area on the top of the N15/5 unit. This will allow the case to "crack"open at the middle seam , which in turn gives you some room to work between the key tumble and the N15/5 black plastic case sleeve it sits in.
- 11.4. The next trick requires you understand how the key tumble is held in the N15/5 sleeve. About 7/8 down the side of the key tumbler, is a cam leaver the "pops" out from the tumble cylinder into a channel in the black plastic sleeve. This is what prevents you from just pulling up on the tumbler to remove it from the N15/5 unit. Tamper preventing, good for car theft protection.
- 11.5. So the technique here is to slide a thin feeler gauge or other such "blade" between the tumbler and the sleeve and "slide it" / " giggle it" around the sleeve to push the cam leaver back into the tumble assembly then lift out the tumbler. easier said then done.
- 11.5.1. Insert the key into tumbler, and move it to switch on ignition. This will lock the key in the tumble and give you something to pull up on.
- 11.5.2. With the 2 case clips remove, insert a wedge (screwdriver) between the seams of the N15/5 case to open up a gap between the 2 halves and the tumble / sleeve.
- 11.5.3. Note the vertical black plastic notch on the sleeve that keeps the tumbler from just spinning when the key is turned. This vertical notch in the sleeve is located on the drivers halve of the case, at the edge of the seam (driver side) that is between the key and the shift lever. If we call that seam the 12 o'clock position when looking down at the tumbler and shifter, then the vertical notch goes from 11 to 12. The tumbler cam leaver is then 7/8 down in the sleeve starting at the 9 position (thinest) and going to the 7 position (thickest).
- 11.5.4. So the trick is to insert the feeler gauge / blade in at the 10 to 11 position and try to slide / giggle it around to the 9 to 7 position to press the cam leaver back into the tumbler then pulling up the tumble by the key you inserted into the tumble.
- 11.5.5. Take you time, be patient, use a bright light to look down in the gap between the sleeve and the tumble to get orientated to what it is you are trying to do. It took me a few minutes of trying to get it to free up.
- 11.5.6. I ended up making a "blade" out of some thin copper scrap metal I had. I thought of using the metal for a Coke can, as it is already " curved", but it never came to that for me. The copper blade did the trick. A feeler gauge may be the best route, but I didn't want to bend them if I didn't need to.
- 11.5.7. Once you do get the tumbler out, it will all be obvious to you what you were doing blind. :nerd:

12. Now just work backward, insert old tumbler into new N15/5 unit.
13. Reconnect cable and plugs.
14. Test new N15/5 for P/R/N/D (may be tricky with Driver Seat out

) Be careful not to move the car or hit anything (parking brake will help here :wink: )
15. Assuming success in test, reinstall N15/5 to floor, seat(s), cover, position indicator, shift knob, and case / cup holder. YMMV. :cheers:
Thanks to
evilution for some helpful hints, prompt email replies, and a discount code for
emanualonline for MBenz (including smart) Service manuals on the cheap :cheers: