I have '94 E320 4 dr Sedan. The check engine light is on. I read in the manual that this is either fuel injection or smog equipment and sounds like the air pump is making noise (bearings going bad). How can I find out for sure why the check engine light is on. Is the deal the only place that can do this? Or is there something aftermarket that I can buy to read it and if so what about codes?

 

A '94 E320 will display this message for a variety of reasons. When hooked up at a dealer's computer diagnostic system it will show: Needs plugs, wires,etc, Needs rear axle mounted speed sensor module, or Needs ABS Control Module. The technician can test to determine which one. The latter is over $1200! Many of us are enthusiastic about our Mercedes. We repair them as we can afford to do so, but there are some repairs that are absurdly expensive and give us reason to think about the worth of spending huge chunks to keep this decreasing valued fine car going. P.

 

Hi: On the 94 you can get the codes down from the impulse counter yourself without the need to go to the dealer. The terminal is a small black box located in front of the battery. Pull the top off and you will see what looks like a female plug with a bunch of connector points. One is a red led and one is a black button. Hold down the button for 3 seconds and release. The LED will blink a specific number of times to indicate the problem. Once it stops blinking again depress the button for 3 sec. If it repeats the same number of blinks, then that is the only code recorded. You clear the code by holding the button down for 8 seconds after the blink serious. Do this witht he car OFF. Repeat the 3 second read and 8 second clear until you have all the codes recorded (# of blinks). Now you need to know what the # off blinks relate to. At this point I would suggest you get an aftermarket service manual that will show the list of # of blinks and what they mean....or....go to www.alldatadiy.com sign up for a years worth of online access to their database for your specific car. It isn't that much and once you figure out how to navigate through (it can be rather frustrating) there is lots'a info.
Good luck and stay away from the dealer.
Have you had the wiring harness replaced on that car yet?

 

Just to clarify the process of obtaining the codes, the engine needs to be off, but the key must be in the "on" position.

Hold down the button for 3 - 4 seconds and count the blinks. The number of blinks is the code. Repeat the process again. If you get the same number of blinks, you have just one code. If you get a different number of blinks, then you have more than one code.

When finished, turn the key off, then back on, and hold down the button for 6-8 seconds. When you start the car back up, the CE light will be off.

The only codes that will cause a check engine light to illuminate are codes relating to smog equipment. Your ECU will hold a lot of codes that will not cause that light to come on.

Here are the codes:

1 No faults.
2 Oxygen sensor inoperative.
3 Lambda control inoperative.
4 Air injection inoperative.
5 EGR inoperative.
6 Idle speed control inoperative.
7 Ignition system failure.
8 Coolant temp sensor-open or short circuit.
9 Intake air temp sensor-open or short circuit.
10 Voltage at Air Mass sensor too high or low.
11 TN (RPM) signal defective.
12 Oxygen sensor heater open or short circuit.
13 Cam position sensor signal from-EZL/AKR ign. control unit defective.
14 Intake manifold pressure at start too low.
15 Full throttle Info defective.
16 Idle speed info defective.
17 CAN Data exchange-Malfunction between control units.
18 Adjustable camshaft timing solenoid-open or short circuit.
19 Fuel injectors-open or short circuit or Emission control system adaptation at limit.
20 Speed signal missing.
21 Purge switchover valve-open or shorted.
22 cam position sensor signal defective.
23 Intake manifold pressure w/ engine running too low.
24 Starter ring gear segments defective.
25 Knock sensors.
26 Upshift delay switch over valve-open or shorted.
27 Coolant temp sensor deviation between sensor ciruits 1 & 2.
28 Coolant temp Sensor.

Post your results and I might be able to help you with the fix. There are two codes (#5 and #26) that are extremely common that have easy fixes.

 

Thanks for that. I do get periodic #26 which I just clear and ignore. What is the fix? I have just replaced the K1 valve spring in the transmission valve body to fix a "flare" in the 2-3 shift. I thought that might have fixed it. Haven't had the #5 / #8 /#10 codes since I put a new wiring harness in (supplied by MB after some "discussions") Thanks Brian... PS :I don't think you need to leave the key "ON" to get the codes, at least I don't.
Bye

 

The #26 code is for the upshift delay valve. This delays the shift from 2nd to 3rd gear when the car is cold for about 45 seconds. The purpose is to warm up the catalytic converter quickly

There are two parts to check. The cheap one is the upshift delay valve which is mounted on the fire wall behind your brake master cylinder. It has a black line (electrical) and green line (vacum) attached to it. That part might be bad or the vacum line might be plugged up. It is only $20-$30, so it might be worth the gamble.

The other part is the mechanism that the vacuum line attaches to on the transmission. The dealer also calls this part an upshift delay valve, and it costs about $225-ish.

On my car, when the key is in the off position, the Engine Control Unit (black box) has no power going to it, so when you press the button, nothing lights up.

 

Thanks again......I see you have the Euro Lights. I also have a 90 300E that I want o upgrade with the euro look but don't want to waste money on poorly fitting aftermarket lights. Which ones are you using and are you happy with them? Brian

 

I have original OEM Bosch Euro's, which are very expensive. but are perfect. The light output is about 400% better, and that is not an exaggeration. They also make the front of the car look much better.

A good way is to go with a brand called DEPO. They are made somewhere in Europe, and are about half the price. Many of my friends in a Mercedes Benz club have installed them on their W124's and W126's, and the fit and finish is the same.

I have held them in my hand and compared them to my OEM Bosch and couldn't tell the difference.

This site sells the DEPO brand Euro's:

http://www.importvision.com/PickAcce...des#Headlights

For OEM Euro's try:

www.puma-access.com hella euro lenses

www.capitolwest.com bosch or hella lenses

 

Hi again, I've got a question that I hope somebody in your MB club may have an answer for. I need to replace the lower control arms in a 94 E320. These have ball joints that are not servicable. In fact, all I need to replace are the ball joints.This is the second time I hade to do it. I want to put in a set of lower control arms from a pre-94 300E with the servicable ball joints. So I need to know if it can be done. It will make changing the ball joints alot easier in the future, which no doubt will need to be done, again.
Replacement OE lower control arms for this model are $300 +-/ea. Oouucch!!
Any help would be appreciated.
Thanks
Brian

 

Lower control arm bushings are an advanced repair. I would not recommend a DIY'er to do it. It can be dangerous if the springs are not handled with care. You need a special tool to flare the ends and to remove them.

I don't know if you're right that "pre-94" W124's have serviceable ball joints.

For one thing, 1993 300E's (3.2 or 2.8) and 1994 and 1995 E320's have the same chassis number. So, for your point to be correct, it would have to be "pre '93" models.

The "Mercedes Benz club" that I referred to is just a bunch of guys from the www.mercedesshop.com forum. We have GTG's from time to time. There is actually one in Huntington Beach, California this Sunday (rain or shine).

It is actually the best Mercedes forum for technical advice on the world wide web as it is moderated by many MB technicians all over the world.

Go to that site and look around. That forum has been around for about 4 years, and the archives are incredibly detailed. Try the search function first under "lower control arms" or "ball joints".

If you dont' find what you're looking for, post it under the Tech Help section.

 

I have 94 E320 Sedan. I just had the check engine light on 3 days ago, brought it to Mercedes-Benz shop and they diagnosed that my transmission upshift - delay valve has a leak. I am not sure if this is the same as transmission modulator valve? Any thoughts? Thank you!

 

Transmission Vacum Modulator Valve!

Yes, that's the correct word for the part that is on the transmission.

The cheap part that is mounted on the firewall behind the brake master cylinder is called the upshift delay valve.

 

Hey Perr2k: Don't worry about it. Just read the earlier part of this thread and learn how to read then clear those codes. The Upshift delay (code 26) is intermittent and isn't anything to worry about. Mine has been acting up for 2 years (same car). Sometimes it stays off for weeks. Up to you, but if the cheap fix doesn't do, don't worry. Just clear the code yourself and keep on truck'n. My friend, who is an MB tech, says it is a nuisance code and isn't an issue.

 

do these numbers correspond to the number of blinks of the LED? My CEL came on yesterday and it gave me 5 blinks and 6 blinks. What is the fix for #5 that is so easy?

 

Yes, the number of blinks is the code.

#5 is an egr fault. The original egr valves had a problem with sticking. If you think it is original, then change it.

The common problem, though, is a blockage in the hot inlet pipe, that exits the egr valve, snakes around the back of the engine, and enters the intake manifold. This pipe gets blocked with oily pcv vapors.

You can try and ream out the pipe, or better yet, replace it. The replacement pipes are a little bit longer, and this apprently prevents them from caking up again and becoming blocked.

 

Hi,
I have 1994 E320, the check engine lite came on and the car rev at idle between 500 and 1200 rpm. I retrived the code from the unite and found it to be #10 "10 Voltage at Air Mass sensor too high or low".

Please help me in fixing this problem. Does it require new MAF or Air heat sensor or both. Thanks

 

You need a new MAF...see if you can find just the insert. That's all you need. You will have to make a tool to remove the old one. Or, just get a whole new unit.....but that is your problem.

 

Have a look at these on Ebay...Cheap fix. 140033688610

 

Looking at the list of Blinks I am getting the 17: CAN Data Exchange malf.
What can I do to work this problem? Am on ALLDATA and they are showing me #4 fuel injection short or grounding...

Have a 94 E 320 that I love very much except for the inadvertant engine shutdowns...grrrr bad car! bad car!!

 

I thought that MB USA were in complete denial about the wiring harness issues on the 320 series cars. May I ask how you managed to pry a new harness out of them? Please elaborate on the details of your "discussions"...

Thanks!

Obviously, I need a harness...

And a GenII amg front bumper....

 

Have found the problem and see it is actually under my feet (in the car that is)...ALLDATA is all of that!

P.S. also printed out the recalls for my car and will be seeing a dealer soon...

Baby needs a new pair of shoes!!!

 

This weekend I have been trying to check this thing of the led blink and all this codes. But I just cant find the way to make it work.
I find a little box in front of the battery, which I open and see a little black box, with numbers from 1 to 16. If this is the box you were talking about?, I just didnt find the way of making it work.
I would appreciate any pics or good explanations of this, it really interests me.

Thanks a lot