I was getting erratic RPM behaviour along with stalling when starting when cold.
My scans pointed to the DPF being clogged via the pressure differentials before & aft of the DPF so I took it out, Liquid Moly'ed the thing and put it back in along with a new temp sensor, Exhaust Back Pressure sensor, & a oil catch can off the EGR.
Did a DPF regen on my Foxwell and it shows nice low pressure now however the erratic idle on cold start remains.
The one code that popped up still after all that was the 0105 code
So I replaced the MAP sensor and low & behold my erratic idle is fixed however I am now, for some reason, in erectile dysfunction mode not being able to go over 3000 RPM.
A new code is the 2025-2 which would suggest it is the MAP I just replaced & the new EBP sensor is bad as well, WUT?
And why I am now getting the DPF air flow too small now as well? What the heck is going on lol?

I suspect the catch can is allowing too high of air flow as well so I should try & reduce that as I used 5/8" ID hoses.

Cheers for any ideas & input.

 

Can you check if by mistake you connect the Air Filter pressure sensor connector to another sensor nearby?


About:
"I was getting erratic RPM behaviour along with stalling when starting when cold."

I would inspect the silver pipe from EGR to mixing chamber.

 

Cheers for the reply.
Haven't touched anything at the front of the engine & generally Mercedes have proprietary connectors for each sensor.

 

Yeah, but it happens sometimes.

Disconnect Air Filter sensor and check with your Diag of the Fault code regarding this sensor became Current

 

Yeah the same B5/1 code was present before replacing and is still present after replacing it on Friday, one would think that sensor was faulty but it immediately solved my erratic idling/stalling when cold but introduced the limp mode.
That limp mode would present itself very rarely at the start of all of this however.
I can disconnect it and do a scan to see.

 

I mean B28/5 the sensor from Left air filter case

 

Drivers side?
If that's the one you are referring to?
If so, that's the one I replaced on Friday, sits in the air filter box and is the MAP sensor.
Or are you referring to the left side when facing the engine from the front?

 

The Left side is the Driver side
B28 is pressure sensor downstream air filter
B15 Charge pressure ( charge,=boost) is in front of mixing chamber

 

Isn't the B5/1 code referring to the MAP sensor or is that a different sensor?

 

Read again previous message, it's edited

MAP means Manifold Absolute Pressure

 

Yep I know what MAP means but that is the one I replaced that sits in the driver's side airbox.
I understood, from reading here, that the B5-1 code generally points to the MAP, no?
Thanks for the edit, you wrote B15 I assume you mean B5-1?

 

Air filter case is not Manifold, agree?

Generic all pressure sensors can be named MAP


Bx/X from my messages is only based on your posted diag scan.
B28/5 is pressure sensor downstream air filter
B5/1 Charge pressure ( charge,=boost) is in front of mixing chamber

 

OK, well the sensor I purchased that sits in the airbox is called a Manifold Absolute Pressure sensor.
That is the one I bought & the one I am referring to which I replaced that corrected the idle issue.

Mercedes calls that the MAP sensor so.... ¯\_(ツ)_/¯

Here's the part I bought.

https://www.fcpeuro.com/products/mer...sor-0261230189

I am lost on why you are mentioning the B15 sensor as my codes do not indicate that sensor?

 

I only read into your Fault codes scan posted above.
Sorry, not B15 it was mistyped
Charge pressure B5/1 Current and stored

 

All good!
So is the B5 sensor the one you pointed out on the frontside of the engine still or is that the new sensor I just bought?

 

You bought the B28 and in your Fault Codes list posted this is "stored" now,. So is OK.
In the same list you have a Current Fault code ( meaning that's still present) about B5/1. And this is not OK

B5/1 - if we trust your diag equipment - is named Charge pressure sensor and yes is the one in front of the engine

 

Well minus the code giving me a "voltage too low" on that new sensor
I need to find that part number for that Charge Sensor now.

 

A 006 153 99 28

But I will diagnose once again with the sensor connected and once again disconnected. This way you can draw some conclusion before you buy a new sensor.

 

Ah so that is the same sensor as the one I just bought, so they use that same one for the airbox and front.

 

You didn't bought a Mercedes sensor, so I would crosscheck at Bosch website if this is the same or not.

In Mercedes Parts program the codes is different, so one could be Absolute and the other one can be Relative
You can try, at least for testing with the one you took it out from the Air filter cover.

 

Yeah this is the one that I bought

005 153 50 28

 

Close enough, as you bought BOS-0261230189 and the shop claim that is equivalent with 005 153 50 28 ( this is MB code, first one is Bosch code).

Anyway, in your first post it seams that the Charge pressure sensor was the first Fault code and you still not verify or changed the correct one.

I would install the original back on airbox and continue the diag.
I can guide you step by step how to make a proper diag.

 

Thanks very much I really appreciate you responding, this form tends to be quite dead regarding getting replies. I'll keep you posted later on today when I check regarding getting replies. I'll keep you posted later on today when I check us

 

Ran outta time today, tomorrow I will tackle it and report back with the scan info.
Cheers

 

Removed the plug and scanned, same result suggesting that that sensor is bad I suspect?
Seems that my DPF Pressure Sensor is toast as well, I bought 2 news ones to have as spares just in case.