In 1996, BMW M introduced a manual transmission that was capable of shifting gears automatically without the use of a conventional clutch pedal or mechanical shifter lever. The system was called the SMG I. Derived from Formula 1 racing technology; SMG stands for Sequential Manual Gearbox.
SMG stands for Sequential Manual Gearbox. It's essentially a transmission capable of functioning as an automatic, or functioning as a manual transmission. Internet software for mac. The innovation is that, when functioning as an automatic, the driver does not need to operate a clutch pedal, simply designate desired gear. Computer operated clutch and the SMG still has to be driven like a manual (let off throttle, shift) most consumers drove them like automatics causing high failure rate. BMW SMG gearbox Non M-series Ferrari & Maserati F1 Transmission Ford Transit Durashift/ASM HPU 2001-2006 Audi BMW DCT transmission Mitsubishi ACD/AYC About us. Canon lbp6030w for mac. With over 30 year's of experience in automotive and heavy duty sectors. Serving customers worldwide, the MLR team is known for system solutions that have kept our customers on the road. Especially on hot days the car can drop out of gear or show the gearbox warning light (SMG cog light). Often the following codes appear in the error memory: 56 (0x38) Switching-on time of hydraulic unit 53 (0x35) low level of pressure reached HE. By Greg Wilson The Sequential M Gearbox is essentially a six-speed manual gearbox where the clutch and gearbox are operated electro-hydraulically by a computer in response to the driver pulling on two paddles behind the steering wheel, or by pushing a floor shifter forwards or backwards. There is no clutch pedal.
The U.S. received the first SMG in the 2001 E46 M3. This system was referred to as SMG 2. The 6-speed manual gearbox manufactured by Getrag, operated in automated “A” mode and performed similar to an automatic transmission or in sequential “S” mode, which allows the operator to shift manually through the gears.
In sequential mode, the driver shifts up and down through the gears by simply operating the shifter lever or a pair of paddle shifters mounted on either side of the steering wheel. Individual gear selection is realized by electrical/hydraulic actuation of both, the gearbox selector forks and the (conventional) clutch assembly.
System Components
The SMG II system is consists of the following components:
- Basic Gearbox (S6S420G, Getrag type D)
- SMG II Control Unit (Siemens)
- SMG CAN Bus
- DME Control Unit (MSS54)
- Hydraulic unit and solenoids
- Gearbox Actuator
- Clutch Slave Cylinder with PLCD (Permanent Linear Contactless displacement)
- Shift Lever Module with Shift Lock
- Steering Wheel Paddle mounted switches
- DRIVELOGIC Control
- Display in instrument cluster
- DSC control unit
- SAC dry single disc clutch
SMG II Control Unit
The SMG II Control Unit, installed in the E-Box next to the DME, is a single board module with SKE (134 pin) gray colored connectors. The unit contains protection against reverse polarity and overvoltage.
Communication with the DME is via a dedicated CAN bus (SMG II CAN Bus). Based on instructions received from the DME the SMG II control unit manages the clutch solenoid valve, the selector shaft up and down solenoids, and the selection angle solenoid. Safety functions and limp home capabilities are also part of the SMG II programming. My blood for mac.
While the SMG II control unit receives many of the inputs and manages the control of the hydraulic system, the DME is responsible for and controls all gearshifts. Sensor inputs received by the SMG II control unit are relayed to the DME for processing and monitoring.
Smg Gearbox Bmw E46
SMG CAN Bus
The SMG CAN Bus is the link for signal exchange between the DME and SMG II Control Unit. It allows the DME to issue command instructions for clutch and gearbox control as well as shift sequence and enables SMG II communication with the vehicle CAN BUS via the DME.
Signals exchanged via SMG CAN Bus:
Engine Speed, Engine Coolant Temp, Engine Oil Temp, Intake Air Temp, PWG, EDR Feedback Pots, Wheel Speed, Transverse Acceleration, Steering Angle, Cruise Status, Parking Brake, Door Contacts, Brake Light Switch, Key Memory
SMG II Diagnosis
The SMG II control unit is fully diagnosable and can be checked using ISTA/D. The first step involves the fault memory being read out. Malfunctions are communicated as part of the SMG II control unit’s self-diagnosis. The second step involves appropriate operator prompting to facilitate diagnosis with simple measuring equipment using test modules.
Repairs can be made once the fault in question has been found.
The diagnosis including self-diagnosis can only be carried out when the ignition (terminal 15) is switched on and there is a supply voltage of at least 10 volts. Erroneous fault entries may be recorded if the supply voltage drops below the threshold of approx. 10 volts.
Service Functions
A test program (service functions) must be carried out upon completion of various types of work on the SMG system – see the following table. The test programs serve to implement test, initialize and adjustment functions.
The values determined are permanently stored in the non-volatile memory only after the test program has been success-fully completed.
*****UPDATED*****
Checking & topping up fluid level in hydraulic system (S6S 420G SMG)
- Turn on ignition
- Press brake pedal
- Move selector lever from position “0” to “R” or “0” to “E” until hydraulic pump is activated
- Wait until hydraulic pump shuts down
- Open expansion tank (1)
- Fill expansion tank up to MAX marking (2) on dipstick (1)
NOTE: Check when cold. Check with dipstick on cap; for this, screw in cap.
The e46 M3 is actually one of the most reliable cars BMW has built in the last 10 years . . . unless you have the SMG option on your transmission of course. The first generation SMG (or Sequential Manual Gearbox) transmissions have not held up well over the long run and are starting to empty the pockets of their loyal owners. So if you are in the market for an e46 M3, stay clear of the SMG. If you currently have an SMG M3, this may be what you’re in for if you haven’t had the pleasure already.
When the e46 M3 came to market with the SMG option, it was widely assumed/stated that if there were any issues with the transmission that it would warrant replacement and that they were not to be serviced. Nor was any service attempts to be made. However, us being technicians/mechanics, it is in our blood to just fix things. Sometimes we can go to great lengths to do so.
We belong to a large group of Independent BMW Service shops that regularly email each other when strange problems arise; to date I have about 60 email threads focused solely on the SMG issues and the failed attempts to fix them. The replacement parts are expensive, none of them can be returned, and attempts to fix a failing SMG usually wind up with the shop losing it’s ass and the customer about to sue. It’s quite depressing to read the trials and tribulations inflicted by our friend the SMG.
Prehaps the most common problem with the SMG will be that of the skip shift. You’ll be driving around town, cruising along, listening to some tunes and minding your own business; everything is A-OK in your M3 world. Then some dipshit with the latest Mitsubishi with glowing paint and the ugliest wheels you’ve ever seen wants to mess around. His blasting ‘music’ sounds like something the military would use to get terrorists out of a lock down and the bass is so loud it rattles his car on every hit and almost knocks off his flat brimmed Hurley hat. You say ‘time to teach this punk a lesson.’ Light turns green and you start to see his plastic horsepower machine in your rear-view until it’s time for 3rd gear to kick in. All of a sudden you slow down, he flys by, and you see a flashing ‘4’ in front of you and a Mitsubishi off in the distance. FAIL.
If you experienced this yesterday, I suggest you take the day off from work, detail your car and get ready to trade it in for something else — you deserve a new car anyway. Of the 60 email threads, this one has proven to be the most daunting and haunting. Here’s an excerpt of one email:
We also had some issues couple of years back with one that had similar faults and symptoms, We put in new clutch, new control pump, etc. Still no go, new shift housing, no go. New gear box, car went.
I haven’t spoken to this shop personally, but I would almost have to assume that this was a personal car of the owner. The failed attempts to fix the SMG issues before ultimately replacing the gearbox would probably total in the $3k range. With the gearbox itself costing over $7k. So now we are up to $10k in attempted repairs until we have found a fix. Ouch. I’ve got countless documented cases of this symptom/fault with the SMG and they have all resulted in the replacement of the gearbox, with the shop eating a large amount of the bill and the customer being irate about their bill. Ugly, ugly, SMG.
With all that said, there are a number of symptoms that have been able to be fixed. Unfortunately none of the parts to do so are cheap, and in many cases a recommended repair will not guarantee success. So if you currently own an SMG car, let this sink in, digest it, and then decide how much you love that car as it might cost you big time in the future. If you are considering the purchase of an SMG car, you might want to think twice or make sure you get a bullet-proof warranty that specifically states that the SMG transmission and associated parts are covered. Unfortunately I’ll continue to have the great pleasure to tell folks “I can do this $1200 repair, but in no way can I guarantee it will work, and you’ll still have to pay the bill as I cannot return the part” Kinda like russian roulette for cars. Pretty bleak.
Take Care and happy paddle shifting.
Chris Keefer
Smg Gearbox Conversion
Independent Motorcars
5836 Autoport Mall
San Diego CA 92121
858-455-5836
Bmw Smg Gearbox Explained
www.independentmotorcars.com