P0412 code

arizonajetta

Active member
Joined
Jul 2, 2017
Location
TUCSON
TDI
2002 JETTA
2002 tdi 1.9 diesel 5spd jetta..... I was replacing a bunch of broken and worn hoses from solenoids when i was replacing my egr valve. And cleaned out the egr cooler. Runs great now. But this code p0412 2nd dairy air injection circuit. Malfunction.... Didnt have any codes before.... I may have put new vacuum line hose in wrong places. .. Any pics out there for this ciruit. And which solenoid is the one that runs this?
 

Rob Mayercik

Veteran Member
Joined
Dec 19, 2001
Location
NJ, U.S.A.
TDI
2002 Jetta GLS, Baltic Green/Beige
Can't speak to the secondary air injection thing off the top of my head, but look here for a vacuum diagram: http://www.myturbodiesel.com/wiki/l...roubleshooting-vw-seat-skoda-audi-tdi-engine/

A little shy of halfway down that page they have photos of the vacuum diagrams from two versions of TDI engine - the under-hood stickers the cars would have had when new. The one you want to look at is the one marked "ALH engine" - that's what you've got.

There's also a thread here on the board that has an ALH vacuum diagram: http://forums.tdiclub.com/showthread.php?t=406760
 
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