Technical P401, P0402, P0638 Trifecta of Error Codes

[666tomanderson]

Hello all, I've had some problems with our 2008 3litre multijet with 350k+ kilometers on it. Symptoms were occasional misfiring and loss of power but, on a recent trip occurred much more often and the van went into limp mode not far from home. A scan of error codes shows P0401, P0402 (both relating to the amount of exhaust gas) and P0638 (throttle body assembly (TBA) ) which a search of this forum and elsewhere indicate a problem with the Exhaust Gas Recirculation (EGR).

As I understand it, the throttle body assembly problem stems from Fiat's questionable design which allows water to flow under the windscreen into the engine bay and onto the throttle body, wiring and onto the bolts securing the throttle body assembly. I'm reluctant to attempt to pull the throttle body assembly off as that action is commonly associated with the sound of snapping bolts I have a good mechanic I trust to do the repair but I'm trying to reduce the labour cost by drawing on the knowledge pool on this forum in the hope that it will negate the need for my mechanic to do an extensive strip and test.

With these error codes, is a clean of the TBA and EGR probably sufficient or will I probably need to replace either or both. Where would you recommend buying the part(s) bearing in mind that I am in Australia?

Thanks!

 

[Kahcorp]

Remove clean check cable to throttle body.
Clean inside throttle body & make sure flap is returning properly.
Listen for the flap moving at engine shut down.
I have removed a few & never broke a bolt on them.
Note, I have replaced one on a 2008 to the later throttle body & adaptor cable.

Check the vacuum lines to EGR & also boost solenoid. Turbo boost sometimes give EGR type errors so don't rule this out.

Note. If EGR valve closes & throttle body flap closes then engine is not getting enough air.

I have pulled of a lot of EGR's & have never come across one that buildup is causing a problem. I have seen those really bad photos online but never seen it here in Aus. Maybe of our longer drives we do.

 

[666tomanderson]

Hi Kahcorp. Thanks for the information. You make a good point about the distances involved in Australian driving tending to limit the build up of gunk. Also good to hear that you've removed the throttle body and EGR on the same year Ducato. Can you post a link to where you got your later model throttle body and adapter cable please? Know of any reliable suppliers of parts for that vintage Ducato ... I'm after the windscreen wiper and lights controls assembly as well but not having any luck so far. If you're near Mandurah in your travels please look me up. We'd just spent a week in Greenbushes and Boyup Brook but had to get towed home the last few ks :-/ It is an interesting and historic area with a number of free camps.

 

[Kahcorp]

I will look up some details for you.
Over the years I got my parts from the UK. I mainly do engine rebuild work but the electrical side with sensors etc & the Comfortmatic side has roped me in to learning more over the past 10 years. There will always be something else that pops up as another issue that is that little bit different.
Funny enough we were in Mandurah last year while doing a lap. The only place we found that we we could easily pack up & move to. We loved the place. The hotrod show was on as well so ticked another box for me. We will be back over to your little State again maybe next year.

 

[Kahcorp]

@666tomanderson
I purchased from Qbec Motor Parts UK
Throttle body 504264089
Febi Bilstein Air Supply Flap adapter cable 47673
On their website there is the throttle body but the adapter cable only shows up on their UK eBay store.

I have a new parts here as I always carry spares for my use & checking the prices now mine went up in value more than a gold bar.

Regarding the wiper / lights on control are you talking the steering column stalks etc.
If so HID Spares in Campbellfield Victoria are the biggest Fiat/Iveco wreckers in Australia.

 

[666tomanderson]

@666tomanderson
I purchased from Qbec Motor Parts UK
Throttle body 504264089
Febi Bilstein Air Supply Flap adapter cable 47673
On their website there is the throttle body but the adapter cable only shows up on their UK eBay store.

I have a new parts here as I always carry spares for my use & checking the prices now mine went up in value more than a gold bar.

Regarding the wiper / lights on control are you talking the steering column stalks etc.
If so HID Spares in Campbellfield Victoria are the biggest Fiat/Iveco wreckers in Australia.

Thanks again. Very useful info. I'll check out Qbec and HID spares for my replacement windscreen wiper and lights stalks.