EGR leak - MAF sensor fault code?

[Tranny-Manny]

2014 2.2tdci custom

Started having reduced power under boost but couldn’t find any leaks and threw the fault code P00BD (MAF sensor circuit error)

Changed MAF sensor and intake air temp sensor to no avail, fault constantly coming on and having to do a rolling restart to get it out of limp mode everytime I wanted to speed up.

Finally got it smoke tested and found a leak from EGR valve so decided to fit a blank and delete the EGR and get the van remapped whilst I’m at it.

Fitted the blank but haven’t got it tuned out yet and the van drives a lot better and throws the code less but is still the MAF error code.

I’m not mega clued up on fault codes and such so it’s a bit of a long winded question but why is it a MAF code and not an EGR code getting thrown up?
I take it when I get the EGR deleted it will stop chucking up the MAF fault?

Thanks for any help and pointers

[knobby1]

2014 2.2tdci custom

Started having reduced power under boost but couldn’t find any leaks and threw the fault code P00BD (MAF sensor circuit error)

Changed MAF sensor and intake air temp sensor to no avail, fault constantly coming on and having to do a rolling restart to get it out of limp mode everytime I wanted to speed up.

Finally got it smoke tested and found a leak from EGR valve so decided to fit a blank and delete the EGR and get the van remapped whilst I’m at it.

Fitted the blank but haven’t got it tuned out yet and the van drives a lot better and throws the code less but is still the MAF error code.

I’m not mega clued up on fault codes and such so it’s a bit of a long winded question but why is it a MAF code and not an EGR code getting thrown up?
I take it when I get the EGR deleted it will stop chucking up the MAF fault?

Thanks for any help and pointers

EGR code will only usually come up if the valve fails electronically....when the valves fail to open, close or seal properly, possibly due to a broken valve or gears in the housing, the PCM sees it as a MAF or MAP sensor issue...it's not smart enough to know the difference. There aren't any sensors on the little gear train of the EGR...so they can be broken and the system may still see the electric stepper motor working as it should. The air flows and pressures within the inlet system/manifold are then not what the PCM is expecting to see....so it calls for help.

When you blank the EGR valve without mapping it out, you still get the incorrect flows and pressures, which is probably why you're still seeing the MAF codes. When you get the EGR valve "mapped out", the system no longer looks for the EGR valve or the relevant pressures and flows the MAP & MAF sensors are supposed to see. It's a fairly simple system really but can be a right pain in the ar$e when it doesn't work as it should.

Lord Knobrot

[Tranny-Manny]

Spot on, thanks very much for the detailed explanation. Put my mind at ease a bit!

Will get the EGR deleted and remap done soon and report back, fingers crossed with no more EML and limp modes!!

[Tranny-Manny]

Got the EGR mapped out the van today, done about 50 miles and no warning light so far whereas before it would’ve been on a few dozen times in that distance. Got the power up a bit whilst it was in too and what a machine now!

Long may the dreaded EML be out of sight!

On to the next thing on the to-do list

[knobby1]

Got the EGR mapped out the van today, done about 50 miles and no warning light so far whereas before it would’ve been on a few dozen times in that distance. Got the power up a bit whilst it was in too and what a machine now!

Long may the dreaded EML be out of sight!

On to the next thing on the to-do list

Result..!

Thanks for the feedback.

Lord Knobrot