same as mine - as I wrote somewhere, I only ever charge via the rear battery - connecting to the + terminal and a chassis ground. Unless doing diagnostic / programming stuff, them its front battery - terminal and a certain one under the little box of tricks up front beside the battery where it tries to short out on the front wing

depending upon spec you can have between 40 and 62 ECU modules in the car all running a RANDOM mix of software and hardware (the full monty of 62 includes one camera and 3 screens - and in the 40 I'm including the Comand and Amp as another 2). And as we see here a few times a year, Merc dealers NEVER update anything other than the Engine ECU and the Gearbox ECU which on a 2006 car was done in warranty and that was likely it for the rest of the cars life - even though any 2007 or earlier car needed at least all 4 door modules and the comand systems telematics ring updating to ensure the windows work and the comand has a chance to operate correctly.

Functionally software updates should be expected to do nothing different (other than Comand update) - its usually to resolve minor glitches the customer tends not to notice, and or improve the diagnostic capability.. A few exceptions, the gearbox was told not to drop to first till stopped, the windows were told to take more stress before giving up, the speedo told the car to put the thing in Park under more situations, a battery save idea making the interior lights stay off unless the light sensor recognises its getting dark etc. (Those last two I just went backwards on to remove as I'm trying to resolve a bug one update did that broke a feature I liked).

On your car check out if the Telematics update was done !!! All pre 2008 221's came with a Comand system that was an utter bag of nails with so many issues it wasn't close to being usable or reliable. The list of bugs is hard to believe possible. There's a massive update that can most easily be seen (to know if it was applied to anything before 2008) by looking in the Map View settings of the Navigation, to see if you have Bird's Eye view. If this is not there don't expect anything on the Comand or associated components to operate correctly. Note mine only got that update in 2014 and one guy did here in 2020 and I know a bloke in Devon that is still on the original. This fix was at least as essential as the gearbox update, but takes far longer so they never bother.

Thats the issue with Merc software - they believe each bit is independent but its not - so many systems you would never believe are interconnected, rely on each other (and indeed on the correct behaviour of another).

The main win of an update is resolving multiple undocumented glitches you might have, to reduce each basket case module throwing its teddies by accident and to add in some cases vastly upgraded diagnostics capabiity - to help garages understand whats playing up for what reason - but on my car what works and what doesn't is hard to fathom. In general on a Merc the SAMs having later software should give more reliability and much more diagnostic support. But when I got the Merc's current software on the Rear SAM (that was a release for facelift cars they believe is still directly compatible with an early car of my spec) it made the Distronic behaviour change in ways that were far less refined and far less safe... I went backwards with a later hardware module running older software - and indeed till I took the Speedo back to original software the graphic of what the radar see's wasn't what it left the building with either.

Front SAM, all Window modules and Comand Telelematics update is only ever a win all early 221 should have





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Thanks Botus - I'll check the "bird's eye view" thing later, although I rarely use the sat-nav. The only software that's been updated since I've had the car is the engine, as far as I know. Today's task is to assess why the new prop-shaft bracket/bearing sounds like a Hammond organ under the car! Are software updates a main dealer only thing? At some point I'd like to get the clock working again as well - there's a place just north of London that offers this but it's a long way to go (from Nottingham) just to get it done!

 

I believe mine has 39. I guess that's why I keep saying it's the base model. It must be the Toyota Camry of S550s

I still can't STAND this behavior. Drives me up a damn wall. I wish it just downshifted at like 5 mph or whatever. Is there a way to get this behavior but also with all of the longevity calibration changes? Probably not....maybe this is a Benz Ninja question.

 

Yep - I have the "bird's eye view" option in the Navi "display mode" so can I assume I at least have the Comand update?
Thanks

 

why do you use 1st ever ? in C it never uses 1st unless you stand on the throttle off the line - it then launches in 2nd and does 10 yards, then realises you want full grunt - so smashes in to 1st with the most hideous noises and drive line shunt, manages 5 yards slightly faster, hits the rev limiter and does a very nasty change back to second

1st is only useful if you need to jump infront of other traffic crossing 2 lanes in front of them - but I only select when stationary rip off the line, and get back to D as soon at the next change happens (that way of working I guess only makes sense if you have the change buttons on the back of the steering wheel)

On my car S is just a nightmare of scrambled design flaws - If I rip it, the box gets muddled and decides it needs to hold on to gears in a very frustrating manner. If I accelerate hard once that's it - I'm now stuck behind the next guy and I want the car to go to sleep again - I don't ever want it thinking it can help hanging on with some mad inconsistent throttle response and mega engine braking for another 3 minutes when there's just traffic in front - If I want the right gear I'll tell it which I want !!!!!!!!!

I've not written this for ages but here we go - the car in S also changes the suspension in to a stilted mess that can't cope with the nasty roads I use in the UK, together with a box that sends the car into mental mode it becomes an out of control dangerous mess - I can drive far faster, far smoother and actually in better control using C

in my world all vehicles - cars and bikes need everything split out. Separate control of gears, suspension, throttle response - BM bikes mix them up - and it just a stilted mess of worse - where you want the comfort ride, but sport everything else

 

you can fix the clock yourself in the next 30 minutes !!!! 5 mins download, 10mins writing if u have a blank CD to hand, 5 mins finding ENG mode, and 8 minutes installing the patch with the engine idling

a great guy from this forum with some special mates wrote the software update Merc later adopted - Polar Bear shared the file here - we then found two models of Comand got missed and I made a later disc that does all the older disc does plus the clock on two late 2007 / early 2008 Comand units one for Europe and one for USA

I forgot to wrap the instructions in the later compressed download but its the disc to make - grab both and get the instructions out the first file download https://mbworld.org/forums/s-class-w...ml#post8494456

 

I have some reasons.

A) It's a 7 speed box. It's not like first is super short. It goes to over 40 mph if I recall correctly.
B) I prefer the launch feel even though I know in many cases it's into 2nd at 10 mph....
C) My feeling is starting in 2nd is harder on the TCC because it seems to be in partial lockup moving this heavy car off the line in 2nd gear. That's more load on the TCC, and it might be in partial lock longer than if it started in first and went to second.
D) I usually drive in S

Aside from the 0 mph downshift requirement, I also find that the torque management (anti-lash I assume) is ridiculously heavy handed from like that 5-10 mph range. It feels so incredibly lazy and laggy. Given my ECU tune I assume this is all TCU calibration.

 

on my 335d with massive torque BMW did the exact opposite of Merc's approach. Sport would only ever take off in 2nd and the car was faster smoother and better (like that exclusively to avoid the shock of too much torque destroying engine mounts and the rear diff mountings) the normal mode using first was only ever an emissions scam pretending a short first could - if driven in a peculiar manner just get better MPG and CO2 ratings

stress on the TC sort of makes sense - but of courses it was designed to operate like this so should cope (the power thrown at it is the same - but of course the action of it multiplying torque - as is the idea of a TC- is supposed to cause damage (like pulling away in top is not good for the TC but I forget why)

I don't believe the lock up clutch will care - they go wrong as they designed it too regardless of 1st or 2nd - the idea is to provide 1 to 1 lock up, and thus better MPG and Emissions under light cruising throttle conditions, it should not be active under take off from rest

the additional changes up and down by using 1st when it seldom needs it (unless trying to run under 6.2 seconds 0 to 60 mph), is just wearing out the box and engine mounts - as I have said many years back (and got slated for suggesting such a sensible idea) one correct in between ratio, in a 6 speed box and one correct suspension set up would have been more helpful than two a muddled up choices of quite nasty compromise - marketing over common sense

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Thanks very much Botus. This is the kind of thing I find challenging! I'm OK with spanners, not so good with computers! Nonetheless I shall give it a go when I get back from hols in October (don't want to break it before then ).

 

if you have a recordable CD drive in a windows PC and a blank std CD-R disc - its as easy as logging on this forum

aside for the odd unit never listed to take the disc, thus a few didn't achieve anything by trying - no one has said they did any damage trying - and the ones where nothing happened most of these we sorted with the later disc supporting two more comand units

 

Taking off in first is easier on the mounts than taking off in second because the gear multiplication requires less engine output. Also, my finely calibrated butt dyno (and eyes on the tach) tell me that just about as soon as you move off the line in 2nd, the TCC is beginning to lock. Try for yourself. You'll see the tach sit at like 1500 rpm but the car will be accelerating. That's almost impossible to do without partial TCC lockup. What it seems to do is partially lock and do so more and more until it is fully locked. But my impression is that it stays in the partial state (i.e. slip) longer than it would if it just launched in 1st and shifted to 2nd. Of course this is WAY the wrong thread for this but whatever....

 

other way around, 1st increases torque through the drivetrain (its why we invented gearboxes) - its why many powerful motorbikes torque limit (engine management reduces power) when using 1st gear

the TC bit I forget - I think the pretend idea of a TC means it can make the vanes inside the TC more stressed if you pulled away in top vs 1st, but as I say they designed it for most people to use C - its a better car but a bit floaty - I guess u have smoother roads and throw them around corners slower or many USA drivers would agree the shuddering mess of the brittle suspension not coping with bad surfaces means the tyres don't grip anywhere near enough to drive fast or indeed safely

 

Yes, but you said engine mounts. First gear puts the least load on the engine/mounts (and thus the torque converter clutches, if it's locked) for a given torque at the driveshaft.

And yes I have no concerns about taking off in 2nd from a pure rotor/stator perspective, other than some momentary heat generation. It's the lockup part that concerns me (and that's what fails).

 

if you can apply the most torque to the rear wheels by using the lowest gear in the box - then that must mean the engine mounts are resisting the same amount of torque, as are the axle mounts - as I mention many silly powerful vehicles limit first and indeed some second gear as well (one of my bikes does second gear as well) to protect everything associated with the driveline

TC lock up clutches trip out after a certain torque limit is reached - on my old omega pretty much anything more than a whisper of throttle would drop it out - it shouldn't wear its enabled and again drops out under low torque situations

 

We'll try this the slightly more qualitative way first.

Let's say you wanted to accelerate to 20 mph in 4 seconds. That's 5 mph/second or about 0.15G. A fairly gentle takeoff. The average torque at the driveshaft is going to be a constant, whatever it is.

The qualitative scenario is, imagine doing this in each different gear, from 1st to 7th. As you use higher and higher gears, you will need more and more throttle (torque) from the engine to create the force necessary at the driveshaft. Why? Because each new higher gear reduces the torque multiplication through the transmission. More force will be required at the engine to develop that driveshaft torque. That force is counteracted by the engine mounts. And everything from the TC forward will be experiencing more force in this scenario, in each successive higher gear. Of course at some point we'll need to use WOT and once we are developing max torque an upshift isn't going to result in more force up front - it's already maxed out and we simply won't hit our target acceleration rate.

 

you get wheel spin in 1st - not 7th - because the gearbox multiplies the engine torque - that torque goes everywhere in equal amounts of stress through the driveline

you get clutch slip in third - more easily than first (on a manual with a worn clutch) because you have to try harder to get a reaction (which aligns with some of your thinking) but not because there's more torque, but more resistance to the game one is playing

 

At the risk of annoying everyone...

722.9 has 4.3772 as 1st ratio. 2nd is 2.8586. There is 53% more gear multiplication in 1st vs 2nd. If my goal was 300 lb-ft of driveshaft twist to motivate the car, the engine has to generate 105 lb-ft (300/2.8586) if I take off in 2nd. If I take off in first, I can generate that same 300 lb-ft of driveshaft torque with only 68 lb-ft (300/4.3772) at the engine. Therefore, that is 53% less reaction force needed from the engine mounts. The only thing that complicates this math is exactly what the torque converter is doing. Torque converters multiply torque. However, I still claim that it partially locks 2nd almost immediately and therefore behaves part way between a regular TC and a clutch. I maintain it's still harder on the TCC (the clutch, not the hydraulic part which, as you said, is designed for this aside from thermal control concerns) to start off in 2nd.