I would appreciate information as to the specific location of the Upshift Delay Valve on a 1994 C220 and its accessibility and ease of replacement.

__________________
Okiebenz

It should be right behind the brake booster servo.

A 2 wire plug and an in/out vac lines [ green to trans ]]

OkieBenz - What are the symptoms you are experiencing....I've had some upshift delay problems when cold on my 94 C220.

On the W202 chassis the shift delay switch-over valve is next to the overvoltage relay under the plastic cover at the rt rear of the engine area.
However if the car has a check engine lamp with code P1 700, it doesn't mean that this valve is bad. Usually it means that the control pressure cable isn't being controlled properly.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

I appreciate the responses to my post. Reference the note from moderator M.B. Doc, my question does indeed have to do with a P1700 Upshift Delay Switchover Valve Control code. I was told that the valve probably was defective since the vacuum line to it was disconnected (at the vacuum source) and it was determined that the "switch would not hold vacuum". The only symptom that I notice is that the "Check Engine" light is on. I do not detect any problem in performance, upshift points, etc. which may only mean that the design of this system is more sensitive or responsive to temperature conditions than I can detect.

__________________
Okiebenz

There is a vacuum servo at the front right of the trans. With vacuum applied a fulcrum changes position and causes the effect of the control pressure cable to change (making the shifts last longer for a given time on each start up). On the bigger cars the time interval is controlled by engine temp. On the C220 it is a straight timing issue.

The switchover valve at the right rear applies the vacuum to the servo under the timed interval. Try applying vacuum to the line from the switch over valve (to the trans cable servo). It should hold. Try seeing how much vacuum is at the switchover by teeing a vacuum gauge to the input to the switchover valve. If you have vacuum then try teeing after the switchover and see if the vacuum appears and holds till the time interval passes at which time no vacuum should go to the cable servo.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

REF: 04/03/2002 reply from Moderator STEVEBFL

I have verified that there is 14inHG source vacuum on the input line to the switchover valve. I also have verified that the line to the trans cable servo from the switchover valve will not hold vacuum. Regarding the suggestion of teeing after the switchover to check vacuum existing and holding "until the time interval passes", I assume that is no longer necessary given no holding of vacuum by the servo at the transmission. However, what initiates that time interval, i.e. how can I initiate it and what is that time interval. What is the replaceable/repairable part at the servo and what is the access to it? Thanks. Okiebenz

__________________
Okiebenz

On a 94 C220 how long should this shift delay be active? Is there a timing unit somewhere?

The part you need is the control pressure cable itself. It comes with the vacuum element made to the transmission side. If the line from the switchover valve won't hold vacuum (and is secure at both ends) then this is what is leaking.

The part # is 124 270 22 73 and is an updated part needing part # 000 987 11 45 to plug off the second vacuum line.

The timing is decided inside the control unit (it switches the switchover valve and applies vacuum to the cable element. In the case of the C220 it is just a fixed interval (I think). On others it only takes place below an engine temp and then for an interval.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

I tried to place this image yesterday but my computer had a heart attack. I drug this image through it this morning but it obviously has seen much errosion through the process. It gives a basic view and in the circle it points out the second possible vacuum attachment on the replacement part.

Attached Thumbnails

 

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Many thanks to moderator STEVEBFL for his diagnostic suggestions and for placing the part image on screen. Before I replace the cable ... since the car appears to upshift normally under both aggressive and routine acceleration and also downshifts on demand, is it possible that the cable is not the problem; or is it possible that I am just not detecting the subtle differences in upshift timing that this system provides when it is working correctly. Also, I would appreciate any general comments regarding accesibility in replacing this part. (I love working on my old 240D & find the C220 a bit jam-packed and overly complex.)

__________________
Okiebenz

The point is that the problem is not a performance one as such. Most people don't like the upshift delay, I hate it on my 540i.

If you have verified that the line to the unshift vacuum element doesn't hold vacuum then you have found the problem. It could still be a hole in the line or it could be the line disconnected from the element but if it doesn't hold vacuum it can't do the function and the controller recognizes that fact. To satisfy the controllers desire, one will have to fix the problem.

I wouldn't recommend this job as the cable has to be attached inside the trans and both the basic asdjustment (for shifting) and the upshift point adjustmenthave to me made after installation.

Either that or manually shift it for the first time interval (not sure of that interval)

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Steve, Many thanks for your excellent input.

__________________
Okiebenz