W210 CEL Woes
 

This CEL is driving me crazy. Almost a year ago, I replaced the fuel lines on my 1996 E300D due to a fuel leak that ended up just being the rubber O-ring on the shutoff valve. While I had the intake off, I took it apart and cleaned it really well. After putting the car back together and starting it, a CEL-Check Engine Electronics came on. I checked everything and could not find anything wrong. I drove it for a while with no problems other than the light. The car then started having strange problems. The ETS light would come on and go off occasionally. Then, a while after that, the ETS would come on followed by the speedometer indicator dropping to zero and the loss of the cruise control. This would usually reset itself while driving and would always reset after turning off the car and restarting. The engine started stalling sometime after that. It would quit unexpectedly, usually at a stoplight. It cut out a couple of times on the interstate. I finally took the car to my mechanic who scanned the codes. He found that the changeover valve was giving a code and he replaced it. He also said that the brake light switch, which I replaced a week earlier, was out of adjustment. He said that the brake light switch could cause the engine to stall (I don't know how). I picked up the car and drove it about 15 miles and the CEL came back on. I had to drive it from Atlanta to Indiana the next day and had no problem with the ETS or any engine stalls. On the way back from Indiana, the CEL would go out for long periods of time and come back on. It went out and stayed out for about 2 weeks. I was driving through a parking lot and went over a speed bumb when the CEL came back on. I found some discussion of the K-40 relay and how it could cause some of the symptoms. I replaced the old relay with a new one. After about 10 miles on the interstate, the CEL light went out. I was relieved. The next day, I started up the car and the light came back on. I took it to my mechanic again and he found it was giving the code P0200 and P1476. He cleared them and told me to come back if the CEL came back on. On my way home, the CEL came back on and has stayed on ever since (for about 3 months).

I'm sorry for the long post. This is driving me crazy and I don't know what else to do. I'm hoping someone has had a similar experience or has some suggestions as to what to do. I'm wondering if there could be some sort of electrical problem. Last week, I had three light bulbs (2 headlights, and one side marker) burn out within one day. Thank you for taking the time to read this post and thank you in advance for responding!!

Eric

General thoughts, that is too many CEL's.

I have had the brake switch replaced, fairly common, as is the fuel lines/O-rings. Not certain about cruise control dying. Thought speedo was electronic and if that went to zero while driving, normally a "Display Defective" issue. That happened to me once, restarted car and never again.

Sorry, no background on the K-40 relay, new one on me there.

Mine has never left me stranded ever. Did have the MAF go bad and got a CEL on that.

I posted a thread the other day that basically got minimal attention. It was about as a W210 owner I think CEL's are more common. Had one the other day, turned out to be an EGR flow issue, but it was 8 degrees out, so probably just gunked up and cold and need to do the big cleanout job. I am looking at getting some type of a diagnostic scanner, so I can simple look at it right then and make up my mind if it is a big deal or not, clear it and see what happens. My bride paid the dealer $92 to check and clear a code basically. Well that would have been better spent on a quality tool.

Here is a link to decoding the codes, though one you mentioned is not on here?
http://www.obdii.com/codes.html

I am getting mine back tomorrow after a pesky CEL. I too had the P0200 Code, and it was either P1476 or P1475, not sure which one. However it was related to the microswitch for the resonance flap. Evidently when the flap opened the switch wasnt recognizing it. I will post the results. I was also having a problem that I couldnt get it over 4500RPMs the Service Advisor said this switch was probably causing the driveability issues also.

Please do post the results. I think it has something to do with taking the crossover pipe and intake off and cleaning it. Never got a CEL until I put everything back together and started it up. Thanks for the response.:)

Ok, picked up the car this morning. Here is the text from my RO: "Owner states car wont go over 4500RPMS and CEL is on. Fault Code is P0200 (i wish the had put the actual MB code whether or not it was P1475 or P1476) Roadtest, SDS, Check for codes Checked actual Values, performed Elec. Test, Performed Activation Tests, Performed Vacuum tests. Repaired Connector at Intake manifold Resonance Flap Switch".

http://i5.photobucket.com/albums/y15...E300/p1475.jpg
http://i5.photobucket.com/albums/y15...E300/p1476.jpg

Hope these help. I think what I did when I took off the manifolds I might have tugged on the connector to remove it and broke a connection.

My '96 has had problems like these as well, but not to such an extent. It appears that the most common cause of the CEL is sticking intake manifold flaps. It's important not only to clean them occasionally but to lube them as well. I used to get a lot of CEL's and it was because one of the flaps was sticking. Occasionally I get the ETS message too and it's totally random. The most frequent message I get is Engine Oil Level even though on the dipstick it's still a quarter above the minimum. I guess this one may not be a fault, just an annoying, premature warning, just like when the winshield washer fluid gets down to about a 1/3 and the display starts warning me.:mad: I've also experienced the occasional engine cut-out for a split second, including one yesterday. Other than having cleaned the flaps, all I do is press the Reset button and keep on driving.

Where is this resonance flap microswitch located? It has been a while since I took the intake off. Do you have the part number for it? Thanks for taking the time to post. It sounds like a promising solution for me.:)

Is it this part number B7075-70269 listed as "Elect. Change-Over Valve" on parts shop? I just started up my car and carefully used a srewdriver to move the black wrapping around one of the wires and noticed barely visible arching (spelling?) coming from where the wire enters the connector. I'm excited that this may be the cause of my problems. I'm going to take off the crossover pipe later today and repair the connections. Thanks Again!!

I dont have a part number, however, the change over switch is the one mounted to bottom of the manifold and has 2 electrical connections and 2 vacuum connections one vacuum to crossover flap and other to the manifold flap. Each flap has a microswitch with an electrical connection. I think this is where mine was damaged.

Eureka!!! (Fingers Crossed)

I think that fixed it. I went to my dad's and took the crossover pipe off. The wire on the right connector was pushed across the divider and was touching the other wire. They were both partially exposed and arching. It's something I never thought about looking at before. I separated the wires and insulated them with electrical tape and liquid tape in hard to get areas. I put everthing back together and started it up. To my disappointment, the CEL came back on. I headed back to my house and decided to stop at Advance Auto Parts to have them scan and see what the code was. They were too busy and told me to come back tomorrow. On my way home, the CEL cleared itself. When I got home, I shut off the car and restarted it several times. No CEL!!!:D My drive home was about 10 miles. I guess the code stays for a set number of miles before it will clear. I am very excited and relieved to have this fixed (cautiously of course). I can't thank you enough e300D97, and everyone that posts on Mercedesshop. The information here is the most valuable tool you can have to work on these cars. Once again, Thank You!!!

Eric

Excellent, placed this in a folder.

Give us an update in a few days/100 miles or so.

Congrats Eric!! Glad to hear. Sounds like our problems were similiar. I still think I caused my problem when removing the manifold.

Me too. I knew it had something to do with me removing the manifold because I never had any problems until after I put it back together. That's how you learn, I guess. Thank you again. I can't stand to have a CEL and this was driving me nuts for almost a year. I hope I can reciprocate the favor one day. Thank you for your time:)

I am going to do the manifold/EGR cleaning, fuel line combo (new plugs, but I'll still take them out) in a few months, so I will tread lightly in that area.

Thanks for posting the solution.

Well, it has been almost 7 months and about 7000 miles since I found the problem and I've had no further Check Engine Lights, ETS, engine stalls, cruise control outages, or speedometer malfuntions since. I hope this has been helpful to someone. Thanks to all the Mercedesshop posters who make working on these cars possible.

Thanks!!!