Code #26
 

Folks,

Been a while since I've been here... mostly because I've been busy and also because... well... my 94 Mercedes E420 has been trouble free.

This morning my CE light went on. I checked with the button in the engine compartment and I clearly have a code #26.

After some research, I see it has something to do with an upshift delay. Can someone tell me what this is and what I should do about it? Should I reset it and see if it comes back again?

Please advise.

Thanks!!!

Code 26 means that the trans ISN'T holding the cold engine SHIFTS long enough....helps with catalyst warm-up....usually a vacuul loss or leak.

Thanks Doc. So, what should I check? I did my due dilligence reading here. It seems there are 3 possibilities.

1. a cracked vacuum line
2. a bad valve near the firewall
3. a bad valve next to the trans.

Most common is the vacuum element that is part of the kick-down cable....
look at vacuum lines FIRST...

Other possible is No sig from ECU to SOV to allow vac flow to element.

There are several ways to test , but here is one that helps diagnose fairly fast and easy/simple....
Take the vac hose that comes from the engine off the SOV and feel/listen for vac with your thumb.. once you know you have vac there , take the other hose off SOV [ out hose to trans element]and put these two together with a small piece of tubing.. this eliminates both the SOV and ECU signal ...take the car for a short ride down the street... it should holds in delay gear. If it doesn't , the vac element at trans is the suspect/culprit.
If it does hold, then you know either the SOV is not opening [ allowing flow] or the ECU is not sending the SOV a signal. That can be tracked down with a voltage test or applying 12v to SOV and retry.
As Doc says , most likely trans cable element leaking..common problem, but try other test first...
One can also apply hand vac to line going to element and see if vac holds, but that test is not as thorough b/c it does not tell you if the element/cable are moving as they shoud.. the real time/drive test does..

Arthur,

Where exactly is the SOV? What does it look like? I read that there should be a green hose/line going to it, but I can't find one.

It os up behind the brake booster.
Ther green line is the vac line going down to the tranny . That is SOV out line . The other is eng vac IN line . The two wires are electric 12v. sig from ECU circuit.

Arthur,
Do you know where the location of the SOV on 96' e320?I found a Sov sitting right in front of the fuse box with a green line and the other one is gray.I'm not sure if it's the right SOV.

That should be it..
Test trick:
Connect the green to the SOV in and that takes the ECU sigout of the system
It should then have delay shift,, if not, the cable/element is suspect...

The problem is i found a pair of switch over valve.Anyway i will take pictures tomorrow so its much easier to diagnose the problem.I'm hoping you'll guide me.:)

Fixed (I think)
 

There was a vacuum line (black with green stripe) connected to what I believe is the SOV (Switch over valve). The connector piece on it was cracked. My mechanic simply bit off the broken piece and used the rest to put the vacuum line back on. No #26 since. Of course, it's warmer out now, so I don't know if the error would generate at this point.

I'm keeping my fingers crossed!