W639 in limp mode
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Newbie
Joined: Aug 2023
Posts: 1
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From: Worksop
Vito 120cdi
W639 in limp mode
Hi, I have a 2008 Vito 120cdi fitted with the OM642 engine. Very occasionally when starting the exhaust note sounded much louder (and really quite good), but it ran in limp mode. Switching off the engine and restarting and the extra noise would disappear and the van run fine. This became more frequent until it stayed on permanently and a CEL came on. I’ve checked for intake/boost leaks, exhaust leaks. Code read it with a basic OBD scanner and it gave me a MAF fault. Replaced the MAF with a genuine Bosch one, no difference. Checked operation of the EGR valve which moves freely. I believe the stepper motor to the EGR isn’t working but if I manually move the EGR valve there is only a tiny difference in the exhaust note. Tried the 5 second throttle reset and no difference. Thinking of changing the throttle body. Has anyone any thoughts on what my problem is? Has anyone changed a throttle body on one of these, if so, how did you do it? I’d be grateful for any replies.
Newbie
Joined: Feb 2021
Posts: 8
Likes: 0
W639 CDI120
I'm guessing the MAF fault code is P0101 ?
I have same van and engine, had lots wrong and seem to have fixed it all
If P0101 will not clear then it is because it is the "Adaption" values for the MAF/Air Filter that need to be reset. I only found one code reader that can reset the Adaption values for a Vito. MaxiEcu, I ordered it on ebay and it came from Poland
https://www.ebay.co.uk/usr/maxiecu
I had lots of problems and did the following to fix:
replace boost pressure sensor
replace maf
replace map sensor
replace EGR value with recondtioned unit from ebay. Mine was not stuck but there must have been something wrong with the electrics as kept triggering limp mode
my exhaust back pressure sensor was ok, I tried one off ebay but made it worse so sent it back (not oem)
in addition I've also had to replace:
wire from egr to ecu
resistor fix on swirl motor
new dpf + sensor
new cat
MAF fuse was blown, replaced it (Fuse 20, 5A)- Diesel HFM
New PCV with pipe and sensor
even after all this it was still going into limp mode occasionally, and sometimes needing the "adaption" reset for P0101
Since I've switched to V-Power it's been ok, so maybe the cheap fuel really messes with it
just before the v-power switch I did run 3 or 4 cans of injector cleaner through it on a near empty tank, so maybe I cleaned something
If your EGR is faulty and not opening then the ecu will trigger limp mode as it expects xyz, older engines you could just blank the egr and the ecu was dumb and could not tell the difference, not on these unfortunately
I have same van and engine, had lots wrong and seem to have fixed it all
If P0101 will not clear then it is because it is the "Adaption" values for the MAF/Air Filter that need to be reset. I only found one code reader that can reset the Adaption values for a Vito. MaxiEcu, I ordered it on ebay and it came from Poland
https://www.ebay.co.uk/usr/maxiecu
I had lots of problems and did the following to fix:
replace boost pressure sensor
replace maf
replace map sensor
replace EGR value with recondtioned unit from ebay. Mine was not stuck but there must have been something wrong with the electrics as kept triggering limp mode
my exhaust back pressure sensor was ok, I tried one off ebay but made it worse so sent it back (not oem)
in addition I've also had to replace:
wire from egr to ecu
resistor fix on swirl motor
new dpf + sensor
new cat
MAF fuse was blown, replaced it (Fuse 20, 5A)- Diesel HFM
New PCV with pipe and sensor
even after all this it was still going into limp mode occasionally, and sometimes needing the "adaption" reset for P0101
Since I've switched to V-Power it's been ok, so maybe the cheap fuel really messes with it
just before the v-power switch I did run 3 or 4 cans of injector cleaner through it on a near empty tank, so maybe I cleaned something
If your EGR is faulty and not opening then the ecu will trigger limp mode as it expects xyz, older engines you could just blank the egr and the ecu was dumb and could not tell the difference, not on these unfortunately
Last edited by iLikeVans; Aug 22, 2023 at 12:14 PM.
