94 e320 Code 26

The "Check Engine" light comes on, I dutifully take it to my inde who says I need a "throttle pressure cable" for only $375 + tax installed.

Yesterday, I called Phil at Fast Lane who gave me part cost for a "AT Kickdown cable" and last night I searched the archives and read most all the comments. Feeling semi confident that I could DIY, I opened the hood, looked behind the bake master cylinder and found two yellow "canisters" and one black module with a total of seven cables/hoses and one electrical connector.

After finding more cables/hoses than expected, I need a little help identifying the parts, what they are connected to and do.

The black module
A] Two prong electrical connector (presently disconnected)
B] Black tube without a connection located below the electrical connector
C] Green cable that continues down alongside engine
D] Hose connected to nearest yellow canister

Yellow Canister nearest black module
D] Hose to black module
E] Black cable

Yellow Canister nearest engine
F] Red cable
G] Green cable to passenger compartment

H] "Y" connector from both yellow canisters to gray cable continues down alongside engine.

1] Which [letter] is a cable and which is a hose?
2] What is the purpose of the black hoses (with 2 yellow stripes) that surround the cables at the connections? Do they make the connection or are they just protection?
3] Which one is the "throttle pressure cable" per my inde and is it the "AT Kickdown cable"?
4] Some of the black hoses are splitting open at their connection. Could this be the cause rather than needing another cable?
5] How are the cables/hoses connected, compression vs threaded at the module and canisters?
6] Why did the inde leave the electrical connector disconnected?
7] Inde says 3 hours to do job. Why does it take that long to R&R the cable?
8] How is the cable connected to the transmission?
9] Are there any special tools or tricks needed to do this job other than greasy and gouged fingers?

Your comments are appreciated.
Bob

I work on these cars every day, I even own one right now, there is not a chance in H that I could help with a list like that. If you wish such a list you need a picture to accompany your list.

I can say that if you have this many questions at the easy end of the cable, you best find your best shot at paying some one.

Unless you pull off some Houdini act (I hear it can be done ), you will need to pull some amount of the valve body to hook the trans end of the cable.

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

Maybe I'm ignorant and the codes and descriptions are the same but I thought code 26, (which I also have currently on my '94 wagon) is:

"26 Upshift delay switch over valve-open or shorted. "

I think it delays the shift from 2nd to 3rd when the car is cold until the cat warms up, non?

__________________
dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles

Hi Bob,
It is a problem with the shift point retard- causal chain.
The way it works is, that the HFM-Box operates a solenoid vacuum switchover valve (2-prong black box). In cold engine conditions it lets manifold vacuum (black vac. hose) through to the AT- control cable vac. canister. That sitts on the right side of the AT and is connected with the s/o valve by the green vac. hose. In the canister the vacuum alters the load information coming from the ctrl. cable, so that you get a late up-shift when the engine is cold.
Test the system by evacuating the control cable canister through the green vac. hose first. If it's holding vacuum, ensure that you get manifold vac. through the black hose. Then evacuate the yellow check valve distributors. Test the s/o valve by evacuating and actuating while the connector is off. Use +/- Batt.
All the best,
Dokta

Steve,
I realize I posted many questions. I got on a role and was hoping someone could reference me to an article considering there are many related posts. I wish I had a digital camera to post a pik.

Your comment "Unless you pull off some Houdini act (I hear it can be done ), you will need to pull some amount of the valve body to hook the trans end of the cable." sounds like the justification for the 3 hrs labor. A knuckle buster I am - a Houdini I'm not.

dtf
From what I understand, it controls the shift delay based on the cat temp as you said.

Dokta
Thanks for the explaination. Hopefully, I can get to it this wekend.

To all
It shifts smoother now that it's disconnected.
Bob

What your indie is calling "throttle pressure cable" is what is normally called the "bowden cable".

However, I wonder why he doesn't think the problem is the upshift delay valve.

I'm told that 95% of the time, the problem is that the upshift delay valve no longer holds vacum.

My bowden cable was replaced with the upshift delay valve anyway, for what it's worth (which is the title of a good song by Buffalo Springfield).

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

The control pressure cable includes the shift delay vacuum element and is available in a superceeded part which has to have one vacuum port plugged and has to be adjusted to achieve the shift delay necessary. note that everything below o-ring #219 is inside the trans. The houdini act requires pulling enough through the hole that the cable can be unattached and reattached. I have heard it is posible, never seen it done and would be terribly hard to do on some models. My trans tech does it in a fraction of what the book time is, because he has done it a hundred times.

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

With Steve's comments and pik in mind, I seriously doubted that I could do the job, but I decided to do one more look see. This time Lady Luck was on my side. On the upshift delay valve, I found a 2" semicircle shaped vacuum hose with both ends severely cracked. Knopf MB graciously gave me a piece of generic hose. After installing it, I cleared the code and the "Check Engine" light hasn't come back on.

To reward myself and give a little back to the dealer, I bought a MB key chain. I told my wife the hose cost $14 and the key chain was free because of a Father's Day promo. She believed me on the cost of the hose expecting the high cost of MB parts.

The car was due for a trans service and the check engine light prompted the trans service. $150 for parts & labor for trans plus $27 for the diagnosis. That’s fair. But, now I face a dilemma. My inde estimated the cable job at $375. Although it could be an honest mistake but, I’m surprised they didn’t see the bad hose. Although, I don’t expect a reimbursement on their labor to do the estimate, I plan to explain my free fix to the service writer. Obviously, my faith in them is greatly diminished.

Your comments are appreciated.

Bob