What makes a 300E throw code 16 randomly...."Exhaust Gas Recirculation (EGR)"
 

My 300E randomly throws code 16 (and only code 16).....the "EGR" error code. What triggers this? A faulty valve? Is there a way to tend to it to stop it from constantly throwing the code? Do the switchover valves go bad?

It usually throws the code when I am driving up over a big overpass by my house, then the road peaks and heads downward pretty steep and makes a sharp curve.....throws it almost every time right there if I am going at a good speed....if I go slower it won't trigger. :dizzy2:

The car doesn't care when the code is thrown, runs the same.

Any ideas on what I should check or replace to stop this? What/where is it even "Sensing" the problem to throw a code?

Where are you getting that code description? I don't think it's right. Better yet where are getting the code, what pin?

Its a 1990 300E....californicated model....so it has the blinky LED/Button on it to display the codes.

I am using the MB code sheets....its code 16 on this sheet:

http://www.tglmarketinginc.com/mbfor...E/300Ecode.jpg

I thought it was just the EGR code and not the switchover code.

http://www.peachparts.com/shopforum/tech-help/247432-e320-code-5-a.html

It is just the EGR code....I had been looking at another page of the codes that lists "EGR Switchover valve" as code 16....

Any idea why it randomly triggers the code? I can drive for quite a while with no code, then it will randomly trigger.

The egr ports are probably blocked with soot. Clean the egr system. The egr pipe on my 89 420SEL was completely blocked with soot.

I will check into this....but how does the computer know this is the case? What is it looking at to trigger that code?

My car randomly threw this code as well. I have a 92 190E with m103 motor - California car as well. Nothing seemingly wrong with it and it just threw the code while accelerating somewhere. No change at all in the way the car drove, idled, etc.

I cleared it to see if I could replicate it and observe what conditions it was, but no luck. It's been 1k+ miles since I got the code and I can't replicate it now. Let me know if you find anything and I'll try the same on my car.

That is the same thing mine does....usually during acceleration (actually I think all the times it has come on have been during acceleration).....then I clear it, and it might come on again the same day, or not for a month. Very odd.

A clogged EGR tube will produce higher than spec NOx readings at the exhaust...perhaps the oxygen sensor is detecting this, and the engine management system cannot adjust within parameters...

I poked around yesterday and found a loose vacuum line leading to the air pump valve....the rubber is dried out. I got it to stay in place....but I will replace it. Perhaps that was/is the issue. I will check all EGR/air pump vacuum lines soon....and replace all questionable ones. No check engine light since....

EGR code is triggered by the vac being monitored via the Absolute Pressure switch...a leak at the SOV of AIR or EGR systems will bring on the code b/c they are common engine vac feed/supply...........

Thanks....I think I will just go ahead and replace a bunch (if not all) vacuum line and rubber connectors soon....I have plenty laying around to do it....so I might as well...

Looks like I'll have to do the same. It threw the code again today. It's been a while but I should probably get the soot cleaned out and the vac lines replaced.

I took the easy way out, I just removed and disabled my entire EGR system, it causes a constant code 16/check engine light, but I don't care anymore. :D

And, I am pretty sure that the car runs better now with it disabled.