sshores

Looks like another problem with my 1995 E320.

I just had another A/C compressor replaced, my third one in 30K miles. Anyway, on the way home the check engine light came on. According to the owners manual this means that there is a problem with either the fuel injection system or the emission control system, neither problem is obvious when looking at the shop manuals.

Does anyone have experience with this problem, how serious it is, and what the likely component(s) are that are giving me this warning light. Any experience shared would be appreciated.

ashman

last time mine went on there was some hose that was blocked in the emissions system. My mechanic replaced it and resett he computer all has been well since..

Have the codes read and that should tell you the problem.

AshMan

paul9662

It was the air mass sensor on my '95 E420.

EKL

My was the O2 sensor. But my car ran better than when I fixed it!

Kestas

Your car has a built-in led/sw at the diagnostic plug for code retieval...It's right there next to the right corner of the battery on the right-side firewall that separates the battery from the engine, a little black box with white numbers from 1 to 16. On number two, there is a button. That is the button you press down and hold for 4 seconds. To the right of this button is a little round light. That is the LED that will flash.

Turn on key and push button - hold for 4 secs, release and count the reply code flashes--- continue until all are flashed and original repeats. One flash means No Codes Stored.

Code list:

1 No malfunction in system monitored
2 Heated O2 sensor inoperative
3 Lambda control inoperative
4 Air injection inoperative
5 Exhaust gas recirculation inoperative
6 Idle speed control inoperative
7 Ignition system defective
8 Engine coolant temp. sensor, open/short circuit
9 Intake air temp. sensor, open/short circuit
10 Voltage at hot wire mass air flow sensor too high/low
11 TN-signal (rpm) at engine control module (N3/4) defective
12 Heated O2 sensor heater, open/short circuit
15 Wide open throttle information defective
21 Bad Purge Switch-Over Valve
22- cam posistion sens. signal defect
23-intake man. pressure low
24- starter ring gear segments defect
25- knock sens
26- upshift delay SOV valve open/shorted
27-Deviation between coolant temp sensor circuits 1 &2
28- coolant temp sens.

Sshores, let us know what you find.

mhorn

Do M103 cars have this same trouble code system? I recall seeing the diagnostic port next to the battery, but no button or led light.

ksing44

I have 1995 E320 and my check engine light has come on twice in 7 years of ownership. The first time, at about 70K miles, it was my O2 sensor (sending unit) and just recently it was the kickdown actuator (solenoid I think) in the transmission. At the dealer, the O2 sensor was about $400.00 to fix and the transmission problem was about $750.00, because they replaced the solenoid, the Bowden cable, and a number of seals as a kind of preventative maintenance procedure. I was also told that the light could come on if your gas cap is loose.

I go the dealer now, because my independent mechanic told me that he was not equipped to decode the problems from the car's computer. He is very knowledgeable, so I am a little suspicious of the idea that you can simply count flashes from an LED light. Is that procedure appropriate for the 1995 W124, or is that only for older versions?

E320BENZ

mine was the O2 sensor... light never came back on

sshores

I wish to thank everyone for all their replies. The indication that I got was that the O2 sensor was bad.

I took it to the dealer and he tested the O2 sensor and found no problem. He reset the diagnostics and no fault indication showed. He test drove the vehicle for about 15 minutes and still no fault indication. I would like to know how to reset the computer should it happen again.

Now here is the interesting part. When I tried the radio, it did not ask me for codes. In my original first post I was complaining that I had just had the A/C compressor changed again. From this I would say that the fault was caused by the mechanic not removing the leads from the battery and replacing the compressor, but that's my guess now. I can't prove it, but I can prove that the power to the radio was never removed since it works and I never had to re-enter the radio code.

Thanks to all for the posts, I appreciate them quite alot. Anyone have an opinion on what may happen when the A/C compressor is changed WITHOUT removing the power as the shop manuals require?

Jimbeau

I saw the advice given by Kestas and gave the method a try. A couple of questions though. Regarding the statement "Turn the Key on" , does this mean just to the "run" position without actually starting the car? When doing it this way, I got the sequence 4, 5, and 6 flashes, then it did would not repeat. Does this make any sense? The air pump and several sensors were just replaced on the car by a reliable shop (which is several hundred miles away from where I live), so I will reset the system and try the test again this evening to see what I get.

By the way, the box on my car ('94 E320) has a cover, so the numbers 1-16 are not apparent unless the cover is removed.

Thank you for providing the method.