E320 fault code 26
 

The check engine light came on after pulling out from the gas station. I ckecked the gas cap, it looks tight. I checked the fault codes by counting the LED flashes. The first time it counts 5, the second time 26. If I do it again it repeats, 5 and 26.
I replaced the OVP about a month ago. Does anyone have the codes? Does anyone know how to build a diagnostic tool for the E320 computer?

Code 5 is egr . Go to the DIY and read S.B. article.
26 is the upshift delay system.
Tool instuctions are in the archives.

If you don't have any luck there , email me for the schematic/parts list.

Maybe this should be in the DIY section as it comes up so often and is a pain to keep writing... [ long]

You're right Arthur. Isn't it funny how often both of these codes come up with the M104 engines with OBD-I?

We all know what causes the egr code (plugged up inlet pipe), but I wonder why these cars are so hard on these upshift delay valves? Weird.

<We all know what causes the egr code (plugged up inlet pipe), but I wonder why these cars are so hard on these upshift delay valves? Weird.>

The egr plugged pipe is infamous on 104s, but one should keep in mind that there is also an up-graded EGR valve to replace an earlier one [ sticking was the prob w/original]. There is a TSB on it.
The simple test for blockage is to apply hand vac, [ about 15"]
to the egr at idle and watch for rough idle and egr Snap back when releasing vac. Pipe block will show no idle difference
[Remember , the egr is not energized at idle. So some rough idle problems can be a stuck egr] But that is another complaint...
The up-shift element and cable also went to a newer part, but
it is also possible to have a cable mal-adjustment trip code #26.
Best to check vac. procedures at the sw/over valve first, etc.
Some prefer to run the trans in 3rd for warm-up and BB the shift delay...me included.

Do you mean to put the shift knob in 3rd and drive until the car has warmed up?

And what does 'BB' mean? Sorry for not knowing the shorthand.

I thought in my car (93 W124, M104) the upshift delay valve delayed the shift from 1st to 2nd, so I wonder how putting the transmission in 3rd affects this.

<<Do you mean to put the shift knob in 3rd and drive until the car has warmed up?
>>

That's all. It accomplishes the same basics and I prefer to get my cars up to at least closed loop without having to hang around. It good for everything. [ that is basically what the delay does, but the ecu does it for the driver automatically]

The BB refers to a vac stopage used by some to eliminate vac to certain servos by putting a BB in the line.
The problem with shift delay BB-ing is you will still bring up a code , but it takes a while. Fortunately , code erasure on mine is a simple built in led/sw, so I do it. [ wish it was a code 2 or 3 so I didn't have to wait so long --B.G.]
I believe the code is popped by the diagnostic module comparing vac. changes when the ecu calls for shift relay energy via the vac presence monitor, but not sure . [ SB prob knows more on that]

In case you are still in doubt about BBs, maybe they should be BeeBees. Is it an acronym? It is the small ball projected by a BeeBee gun; a semi toy. Very usefull to permanently plug rubber vacuum lines. I keep a drawer full of them.

The upshift delay feature is monitored by watching engine speed, I presume.

In reguard to the well known 104 EGR pipe, let it be known that we just traced a M112 ML320 EGR code to a thoroughly plugged stainless pipe that carries EGR into the intake from the back of the manifold. The pipe attaches to the EGR valve and is about 8-10 inches with most of it inside the manifold. The car had 80k on it. So looks like we will be seeing EGR codes on all the late cars too as I imagine this is the same on all 112/113 motors.

I have noticed lately that the car is slow to upshift when it is cold so it sounds like you guys are on the right track. Does it hurt to drive the car until it is fixed? Do I need to take it in or is this something I can fix myself? What is the probable cause for the problem and what should I replace first? Thanks for the helping, I really appreciate it.

My guess is that it won't hurt anything. It's only purpose is to let the cat converter to warm up before shifting into 2nd gear. This is to reduce smog.

You can continue to shut off the check engine light everytime it illuminates. You'll just have to fix the problem before your next smog check.

Btw, if it's working it should be slow to upshift. Mine seemed to be doing its purpose. It always held the transmission to a high shift point from 1st to 2nd. It just triggered the fault code. My vacuum hose was plugged and I also decided to change the part. It's only about $27, and it's very easy to replace. It's on the firewell behind the master cylinder.

Which vacuum hose was plugged? Which part did you replace?

I replaced the upshift delay valve. It has I think a green line and black line going to it. The green line is the vacuum, and it connects to the transmission. The black line is electrical.

Somewhere, someone has posted a picture of this (maybe it was Arthur Dalton). He's the Lone Ranger when it comes to these fault code diagnostic issues.

<<I thought in my car (93 W124, M104) the upshift delay valve delayed the shift from 1st to 2nd, >>

Paul,
On your car the shift delay is actually from 2nd to 3rd.
Your car is second gear start ,whereas the E320s are first gear start. [ 124 chassis E320]

up-graded ERG valve question...
 

I have recently cleaned out the inlet pipe on my 95 E320 for the second time, but my CE light (code 5) continues to pop-back-on. I am now starting to think I need the 'up-graded' EGR valve that Arthur mentioned.
Could someone get me a part number, as I can't find mention of it in any of the archieves, and Fastlane does not currently stock any ERG valves for my engine number (104 992 12 075 237.)

Thanks,
-Mike

Re: up-graded ERG valve question...
 

For the benefit of all, I have posted this Recall Campaign # 95-0131 for all the models w/sticking EGRs.
Please print out a copy as I can leave this posting for only 1 week. [ sorry, I just can't tie up my limited space]
Arthur

http://members.aol.com/ajdalton7/egr1.jpg

You know, I've never actually counted the shifts, but I'll take your word for it that the upshift delay is fron 2nd to 3rd.

However, I'm pretty sure my transmission starts in 1st gear, not 2nd.

I remember reading that the change to a 1st gear start began in 1991.