W124 e320 not engaging 5th gear

[kth286]

i have read them on 124s!! pin 11. obviously it is only for the 5-speed box and only regarding the 4-5-4 changes, but hey don't believe me, here it is - page 11.

http://www.motodok.com/Documentation/Files/MB/cs1000-mb.pdf

these 5-speed 124s are fairly few and far between, and the gearboxes in good condition are sought after. our preffered specialist repairer used to pay good money for s/h ones to dismantle for parts.

No.

Pin 11 is the ATA (anti theft alarm)

page 11 shows the layout for the 16 pin diagnostic connector for 124 and 129 cars BUT if you delve further pin 13 is the ETC (electronic automatic transmission) BUT it is for 129 only.

Conclusion: there is no way to read codes for auto transmission for the 124 HFM car.

 

[alexander patie]

sorry kth286, i meant pin 13. you are clearly an expert extraordinare on w124 mercedes and many other models to boot. i have no doubt that you have every reason to believe what you say - indeed reading further on the link i pasted it says ETC diagnosis is only for 129/140 cars!!

however i have fixed a few of these back in the day, two times it was the solenoid in the box going short circuit (on a w124). i thought that i had read the codes on this to trace the fault, in fact i am sure i did - it may have been on a very late model car, some were sold with p-registrations although i think they discontinued the 5 speed w124.... memory may be playing tricks on me here as the evidence does suggest you are quite right. it is possible the diagnostic was actually on a seperate plug, in eg passenger footwell? i will check it out.

if i find a w124 5speed car with/without the pin13 i will gat back to let you know!

 

[alexander patie]

i have been into work today to have a look.

we have various cars in, one of which has the 5 speed transmission. this car is either a 280 or 320 TE - can't remember which - on an 'N' registration.

in the x11/4 connector there IS a connector in socket 13. the cable is white (in black sheath) and goes into the loom with other diagnostic cables. i have never seen sockets in the 16 pin plug (on a 124) that have not been wired to something before.

my memory of reading the codes on these cars is correct, or i am a liar. i will be happy to try to upload some pics if suspected of being the latter, it will have to wait till tuesday night though.

 

[w124coupe]

Being slightly sad, I have just walked to a near neighbour who has a 320CE 5 speed (N reg).

Nothing connected to pin 13! (just a hole in the plastic).

Looks like yet another W124 variable...(like the several different A/C wiring schemes even for cars with the factory fit AC).


to the OP:

my second uploaded doc earlier in the thread gives the approx revs/speed combos you should see by gear - if you just check that then we will know for certain if you are stuck in 4th or seeing a very swift 3->5 change......

the fact you said that you were (a while ago) able to correct the behaviour by waggling the gear selector STILL makes me suspect the "D" switch at the selector - very quick and easy to check/eliminate and not at all expensive to replace....

(there will be no fault code if this switch has failed open circuit.....)

 

[kth286]

alexander

thanks for your valuable posts.

I am as keen as you (and many others) to continue learning - we never really stop learning do we.

So, yes - anything further you can contribute will be good.

 

[ray_hennig]

4th/5th gear issues in 124 300ce-24 5 speed auto

Dear all,

I am very interested in this subject as I have all but lost 4th gear. If accelerating very hard, it will hold 4th for a second or 2 but basically the thing does straight to 5th.

Also, downchanges are very reluctant and manuallly selecting 3rd results in a long wait before 3rd's selected. Downchanges to second are reluctant and slow too.

I could explain everything at length but I don't want to hijack the original poster's thread.

Shall I start a new one or is this on-topic enough for me to bore you all here?

Awaiting your comments.

RayH

 

[alexander patie]

hello ray, please join us here, this gearbox and associated problems are not everyday stuff so the more the merrier.

presumably you are used to the car and once upon a time the changes were fine. if what you say is true the most common cause for this problem will be microswitch in the gear change module, solenoid in the gearbox or possibly a wiring connector near the battery going open circuit.

but there is possibly a way to pin it down, you may have a diagnostic connector under the bonnet which could be interrogated with a couple of pieces of wire and an LED. under the bonnet near your brake servo is a 16 pin diagnostic connector, can you tell us if there is any wiring or signs of a socket in the hole for pin 13? this may help you and inform us at the same time!

many thanks

 

[ray_hennig]

Thanks for the welcome ...

I'll check this and report back as the next few days promise to be busy.

Yes, the box was fine a year ago. The rear engine/gearbox mount was changed and things seemed to go awry then althought I can't be certain. I even wondered whether a vacuum hose had got trapped there - we tested vaccuum lines from the top and all held good.

The problem I have is getting under the thing - I like my food (!) and the thing's quite low due to Sportline etc. I've got a chum at the local 'MOT' station and he's willing to put it up on the hoist. We plan to check ALL vacuum lines as step1.

I'll also check/clean all electrical connections as I have elsewhere - this DOES pay dividends as I have a very smooth idle and start-up is excellent for a 350 KKms car that's 18 years old.

More soon and thanks for your interest.

RayH

 

[ray_hennig]

Diagnostic Socket Comment

hello ray, please join us here, this gearbox and associated problems are not everyday stuff so the more the merrier.

presumably you are used to the car and once upon a time the changes were fine. if what you say is true the most common cause for this problem will be microswitch in the gear change module, solenoid in the gearbox or possibly a wiring connector near the battery going open circuit.

but there is possibly a way to pin it down, you may have a diagnostic connector under the bonnet which could be interrogated with a couple of pieces of wire and an LED. under the bonnet near your brake servo is a 16 pin diagnostic connector, can you tell us if there is any wiring or signs of a socket in the hole for pin 13? this may help you and inform us at the same time!

many thanks

Attached is a shot of the socket by the battery. 13 is populated and a white cable leads back and down towards the gearbox (possibly).

All for now but I'll be back.

RayH

 

[boomtings]

Hi everyone , thanks for all the assistance.

I have not had a chance to use the info to find my fault but will post back when i have done so.

Im positive that its not changing to 5th.
My own test were very similar to the Merc method posted by W124Coupe.

The car should be cruising at motorway speeds and instead im reving around 1.5 to rpm more then normal.

regards.

 

[ray_hennig]

Just back from all day party with Brits in France (!?) but ...

Adjusted duty cycle this morning (I believe all this is related) and managed to get the 50% (I have a Kat) following problems with inconsistent readings. This ought to be a separate thread but I will mention application of WD40 that loosened things up and gave me the consistency that I lacked before - anyway ...

Same old gearbox problem - I expected that.

If I drive the car on our local winding country roads, selecting '3' only, it's great. Downchanges are reluctant but, overall, the old vigour is there.

One thing (should I start another thread on this?), I stopped and left the car running. On getting back in, I slammed the door and revs lept and dipped and then settled. I've noticed this before. Why? Something's loose. I recall once getting out of the car 'chez moi' to do some tests and, on slamming the door, the engine died!!

During next week, I'll try to document the problems I have with 5-speed, M104 300CE-24, in an attempt to condense things down. It seems that our common ground is that spec - is this thread likely to include the later, HFM-controlled 320?

As alexander patie said, perhaps we have an unique set of problems and should bare our soles (is this right?).

More when coherent.

As ever.

R

PS: Just noticed that boomtings has a 320 so we're all in the same boat. Maybe my KE Jet issues aren't part of this.

 

[alexander patie]

high boomtings, if you have the diagnostic socket in the 16 pin connector (some do, some don't) you can see if there are any stored g.box faults with just a piece of wire and an led.

thanks for that ray, now if you want to try reading the codes (there may be none) can you find a suitable LED? it needs to be wired between pin13 and pin 16 (+ve). then with the ignition bridge pin13 and earth for approx three seconds and count the pulses on the led. repeat untill you get the first code back. one blink means no codes stored. bridging for approx eight seconds erases the code. this procedure is from memory so may be wrong - get back to me if it does not work for you.

thinking on, boomting's fault could well be that connector near the battery......

 

[alexander patie]

alexander

thanks for your valuable posts.

I am as keen as you (and many others) to continue learning - we never really stop learning do we.

So, yes - anything further you can contribute will be good.

hello kth286, you seem to be saying 'yes' to my offer of pictures to verify my testimony? if you don't mind i wil decline now, ray hennig also has the same socket and wire on his car and has posted the picture to prove it - thanks ray.

if i were able to upload the pictures which i would have to take on my wife's 7yr old camera, i cannot see how they would add to this thread in any way. so not worth my hassle.

it will be interesting to see if boomtings has the socket or not. odd that some newer cars, like w124coupe's neighbour's, have not got the socket when ray's older car has. i am sure there is some rhyme or reason to it but for now it escapes me..........

 

[w124coupe]

I'm assuming the control unit for this (Merc call it the EATC) is always in the same place on the 124s - behind the ECU behind the battery (its there on my neighbour's car!).

No time to re-read all posts but are we discussing two HFM cars or is one a KE?

I have the pin-outs if needed (to check power supply/OVP supply and signal from "D" switch for example without the need for crawling underneath).

Will be out now until this evening...

Re the door slamming - I would work around the earth straps/points looking for a loose or corroded one (also check all the fuses to make sure they are not suffering the notorious W124 fuse-rot...). The fuse/relay box is not far from the drivers door hinge (under the bonnet) so would get a jerk from the slam).

Lots of W124 issues are related to poor connections - many of the ECU functions use a voltage or resistance value to control maps etc - therefore an additional "false" resistance often causes poor running or various bits to stop working properly.

Assuming the looms are OK (and not rotting!), I recommend new fuses (cheap from Halfords), cleaning of earths and checking of all connectors (often a quick undo/quick look/spray with contact cleaner if needed/redo is enough) as good preventative maintenance when taking on a W124.

 

[ray_hennig]

Totally agree ...

Clean every electrical contact you can, I know I have.

I know I haven't managed to get to them all so I'll presevere.

Mine is a 300CE-24 with KE-Jetronic so there's a 'mechanical MAF' etc.

I imagine the later HFM 320s etc. had the same gearbox so I suppose that complicates things if there's a later car here too.

Another test run today to make sure Duty Cycle has remained spot on and, yes, jumping between 47 and 53%. Still the occasional idle surge but no stall today and gears exactly the same.

Incidentally, I thought the gearbox control was only electrical/electronic for 5th. True?

If so, I also have a very reluctant downchange, even when I've selected position 3. Foot down somewhat and it labours in 3rd then eventually changes to second and 'off we go'. It's as if the 'box doesn't know the accelerator position. Maybe the vacuum feeds are blocked?

Still thinking and testing and will report back.

Thanks again for all comments. Somehow, there's safety in numbers!!

RayH

 

[w124coupe]

Ray, can you post the first part of your VIN so we work off the right info - WDB124xxx.

Given your more general gear issues, I would check the fluid level (when was it last changed?) and also spend a few minutes cleaning, lubricating and adjusting the throttle linkage. These cars need the linkage spot on to be smooth and the adjustment process is different for KE versus HFM and for cruise control cars.

I'm posting off a Netbook accessing my home PC from McD's (sad, I know) so I can't access much.

 

[ray_hennig]

300ce-24

Fluid and filter changed about 18 months ago. Linkages checked and lubricated as best I can without the fat b@st@rd squeezing under the car. I've adjusted this and other MB transmissions with success in the past and, frankly, this one manages it's up-changes beautifully. When under power it performs just as it should. When I demand downchanges, the box just seems to stop listening. It refuses to understand that I've gone from overrun to acceleration (high-vacuum to little-vacuum) and that I now need a down-change. That's why I keep harping on about vacuum issues.

VIN:

WDB124-051

It's in France, supplied to France, left-hand-drive. I bought it from MB with 1 year guarantee under which the entire MAF (the mechanical stuff and potentiometer) was replaced to address a worse stalling issue. It never did - I replaced OVP and cleaned everything and that improved the stalling.

RayH

 

[bolide]

I believe there's a kickdown solenoid - I've bought cars where this has been replaced and it was recorded in the history. I know nothing more about this so please check

I find I need to adjust the kickdown cable on every diesel I buy but rarely need to do it with petrol cars

I would think the best test procedure would be to check the ATF level, reseat the o/s/f carpet mats, check the throttle pedal moves freely, clean & lubricate the linkage, replace the throttle cable if necessary, adjust the throttle cable correctly and make sure the E / S switch does something

Assuming this is all OK I normally ignore the "right" way to adjust the kickdown cable and set it to get kickdown at about 70% of travel. This works well on the diesels with their strange-shaped torque vs throttle position response. The petrol cars would be less critical

Nick Froome

 

[ray_hennig]

Thanks Nick.

Yes, all understood and done. Something deeper amiss but what?

Kickdown works - the switch switches and away we go. It's the normal, everyday downchanges that take forever. We''l get there in the end.

If my economy turned up suddenly, I'd drive 600 miles to my old chum Steve Redfearn in Wimbledon and he'd sort it but, sadly, I'm on me own for a while. C'est la vie.

All the best.

RayH

 

[alexander patie]

have you checked the cable adjustment then ray??

yes w124coupe, ray's car is the 300-24v ke model with the 'mas' relay, so no pattern to which cars have the pin13 (the one at my work with it is an n-reg hfm)