Intermittent Limp Mode
 

Hello All,

Need help in diagnosing a intermittent limp mode issue my 2005 E320 CDI is having. I have been mainly seeing the issue happen during highway driving. I unfortunately don't have a point of reference as to when it happens. Will be cruising along on the highway and then at some point try to speed up to pass and there is a immediate lack of power. No CEL or anything. Simply turning the car off and then back on usually clears the issue. The Issue has been happening since I have owned the car but I finally have time to properly investigate it.

I had previously checked and cleaned the EGR valve. I cleaned all the soot and lubricated the slide that is behind the plastic cover. I had recently disabled the swirl flaps with the resistor mod and beyond this nothing else really. The car does seemingly now need the Glow Plug Module and Glow Plugs. I was never having issues before but after having let the car sit at a friends shop and then starting it after a period of time I got CELs for all the Glow Plugs and the Module itself. I don't believe this is apart of the issue but i threw it in for reference.

Let me know if you have any thoughts or can recommend where i can begin to troubleshoot

Check the codes to start with.
Not knowing mileage I could speculate that you disabled the flaps becouse they were jammed gummed up in the intake? When resistor can cheat the computer, it will not let the air flow via clog passages.

I have recently had a similar problem with my 2006 E320 CDI. At first I thought it was a transmission issue, as when I would accelerate it occasionally would go kathunk, like an uneven or bad shift, then it would get stuck in 2nd (limp mode). I had been able to get out of it by stopping the car, waiting thirty seconds and restarting. Then it got stuck in limp mode and I couldn't get out of it. Took it to a local guy who told me he thought there were some invalid codes and he cleared them and it is back to normal. 192k in miles, for what it's worth. But it doesn't give me a great deal of confidence going forward. Otherwise, the car has run like a top. I bought it a couple of years ago with 132k on it.

Not all that handy so I don't know if it applies, but there seems to be some stuff on Youtube, including this:

All the times the car has gone into Limp Mode there have been no codes. I was just mentioning that the car now has codes but all are related to the Glow Plugs and the module. I was unsure if these components could have anything to do with limp mode given what I described.

There is no limp without code.
You need to get MB specific scanner to read transmission.

I would need access to a STAR tool correct. Do these cars store codes that have been triggered?

Right now you will find whole selection of scanners who will read MB.
iCarsoft MBII seems to be most popular.
Those cars store codes forever until somebody clears them.
Had it happen all the time, that new purchased vehicle has 20-40 recorded codes.
Most of them are from the time the battery died 3 or 5 years ago...