limp mode

[Stue42]

i wonder if anyone can help? i have a 2007 sprinter 315cdi that went into limp mode 3 days ago. got a code pointing towards MAF sensor. i have fitted a new bosch sensor which has made no difference and now have quote
2623. MAF sensor, offset drift at idle
Permanent
the van won't pull at all, can anyone point me in the right direction please?
stue

 

[wongl]

What happens if you leave the MAF disconnected? Will the van pull with the MAF disconnected?

 

[Stue42]

thanks for reply wongl, i'll try on the way to work and get back to you tonight.

 

[Stue42]

hi wongl i ran today with maf disconnected and there was know difference, still in limp mode

 

[Stue42]

any ideas guys?

 

[Stue42]

in case anyone interested, new maf sensor and coding in

 

[unclebuck]

I dont have much info i can help with, but ( if the mods dont mind) there is the sprinter source forum, this is a thread from there with the same issue, read through, last post page 2 may give some info.

Code 2623 charge air system offset drift at idle

Hello guys..Newbie (lurker) from Norway in Europe... 2007 MB sprinter v6 3.0 The famous code 2623 charge air system offset drift at idle I have replaced all o-rings and gaskets from air filter into turbo, from turbo and trough the intercooler, and into engine. Changed air filter, checked...

sprinter-source.com

 

[Tuercas viejas]

To clarify
The major sensors on the engine are providing info to the ECM for fuel mapping and one or more of them is out of whack.
So you need a scanner in live data to find which one!
So you have the principal ones to start with in KOEO and look at the base line figures .
The air pressure sensor (on top of the air filter box ,)
The Ambient pressure sensor (buried in the ECM circuit board )
The boost pressure sensor (mounted on top of the throttle body)
The air input temperature (part of the MAF unit

Now I am assuming you are in the UK so an island & at sea level, so air pressure will be 1000 to 1025 HPa
(I am at 6500ft outside Denver so I see 775 HPa )

You are allowed 25 HPa drift in KOEO between these sensors. (Hence offset drift at idle )
Often one has failed so it will flat line on a scanner at 700HPa . (f you see that its bingo)
The most common are two sensors , the one on top of the air box & the other buried inside ECM .

As a instant diag without a scanner on hand I find the air pressure sensor on the air box being the most vulnerable.
The socket and wires are flimsy.
With a warm engine at idle pull off the connection to flat line the signal (open circuit) the engine sound will change from a smooth singing (like Welsh male choir at the Eisteddfod) to a deep baritone sound like the Red Army Choir.
Go try it and get your hands on a scanner with live date (Snap On is good) open up the PIDS to EGR & look at the sensor figures .
Tuercas Viejas
aka
Lindenengineering on that at Sprinter forum