Vito W639 - P0100 (MAF sensor), P0110 (IAT Sensor) and P0401 (EGR Insuffcient flow) Van is jolting in low gears. Any ideas?

[Nathanjennings]

Hey guys. Vito 115 2.1 W639.

So obviously the van isnt breathing properly but I dont know where to look next. I have intermittent power loss and the van jumps around in low gears. I'm thinking maybe the turbo actuator arm is sezied up? Or theres possibly a small boost leak somewhere? (Have checked all hoses and couldnt find one but didnt look as thoroughly as I could of). I'm idling at around 800 - 900 rpm which seems maybe abit high?

I've already replaced the MAF and have cleaned the EGR valve. Before I cleaned the EGR I had P0406 (Exhaust gas circulation (EGR) sensor A having a high circuit voltage) then after I cleaned it went to P0401 (Insuffcient flow) which comfirms what I thought, that something somewhere is blocked up and air flow isnt gettting where its supposed to be.

Any ideas?

Also is it normal to only get 3000 rpm whilst stationary?

Thanks.

 

[M80]

Yes tick over a bit high.
Normal for restricted revs when stationary.
When the ignition is cycled the turbo actuator should self test and move through its range. It takes 2 though.

 

[Nathanjennings]

Thanks for the reply. Brilliant so i should be able to see the actuator move on ignition? I'll check it out this morning. Any tips on finding boost leaks?

 

[M80]

I've read smoke tests are used for boost leaks, but I haven't experience.
For leaks at the intercooler hoses a simple test, while on tick over is to push on the hoses into their receivers to see if the sound changes.
The problem there is that the intercooler could be with hole, or the hoses may be split. Leaks are possible elsewhere also.

 

[Steve@Avantgarde]

Have you got any fault codes stored?

 

[supernoodle]

Are you sure that the codes P0100 and P0110 are the full codes reported? I expect another two digits after each which are the failure type byte. P0100 says Mass or Volume Air Flow “A” Circuit, the failure byte would specify what the problem is, eg 86 would be Signal Invalid. P0100 on its own is very vague.

Some P codes don't need the failure byte (or tool will report 00) as you saw in your P0406, Exhaust Gas Recirculation Sensor “A” Circuit High, that tells you it's a circuit high fault. As that is just an electrical diagnostic I can't see how cleaning the valve can have resolved unless there was a bad connection or dodgy wire that you disturbed.

Is that IAT integral with the MAF on that vehicle? If so a bit suspicious that they both have a fault.

 

[MinionBob]

Not something I have ever done, but as M80 says a smoke test should find a boost leak. Plenty of youtube vids on how to make a simple smoke generator.

 

[Nathanjennings]

Thanks for the replys guys. Sorry its been a while. I ordered a genuine Bosch MAF from a breakers yard and the problem was slightly better but has returned in full force. As far as I'm aware the codes didnt have any extra numbers with them besides the P0100 and P0101. I'll another look when the CEL comes back on and double check.

With my MAF disconnected the Van runs an absolute dream. Apart from a slight lack of power and obviously worse fuel economy.

I've tested the air intake pipe and intercooler pipe (Only the turbo side) for leaks and cant find any. Gonna have a check of the other intercooler pipe and hopefully find one there.

Any other ideas?