# 2003 Passat 2.8l 6cyl with misfires and misc. DTC codes???



## FrankB4now (Dec 28, 2008)

I have a 2003 Passat 6cyl 2.8l has a problem with misfires, Sec. Air Inj. Sys., Bank 2 Flow too low and one Warm Up Catalyst: Bank 2: Efficiency Below Threshold. The MIL light kept coming on and we took it to the dealer, battery first time, 2 plug wires the second and fuel evaporator last time. Each time it got better and then came back again. I got the VAG software to check it myself and started getting multiple misfires. Through different elimination processes I ended up changing the plugs, plug wires and ignition coil. It kept coming back. I thought it might be a fuel problem with cheap gas. I had put in a good fuel injector cleaner and a full tank of good gas. It really didn't help though. Now I got the other codes P0431 and P1411 along with the misfires still. Another forum suggested checking the SAI system and Combi valve and lines. Does this sound like any symptom of progression that anyone has seen before? I only got two if the P1411 and one P0431. Thanks for any feedback


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## spitpilot (Feb 14, 2000)

*Re: 2003 Passat 2.8l 6cyl with misfires and misc. DTC codes??? (FrankB4now)*

SAI system shouldn't cause misfires..it operates downstream of the cylinders to squirt air into the exhaust manifold to help Cat's lite off quicker on cold starts. If you're gettin SAI codes..check the little vaccum lines that control the kombi valves B4 you jump to any conclusions that you need new SAI pump or valves....those little cloth covered vacc lines fool ya...look good from outside, but under the cloth..rubber can be cracked and leakin..if you lose vaccum..Kombi's won't open correctly and you'll get code for "low flow"....when you pull off the vacc lines ez to check Kombi's..just pull vaccum on em and listen to valve action..if you can't pull vaccumn then diaphram is shot and you need new kombi...you can also check solenoid valve that sends vaccum to kombis when vacc lines are off it..just blow thru it and then put 12v on it and see if you can get air thru it when energized..if so its OK too. I'm bettin its vaccum line issues..mine were all in bad shape...VW knows Kombi hook up is shaky..(right near alot of heat) since they have a replacement kit for the elbow connectors and hard lines for this part of the system...and the elbows are much beefer than the OEM connectors were!..about $20 or so as I reacall...I got mine thru 1st VW parts website..ask Zeb there for "Kombi valve vaccum line kit"...and he'll hook you up. Little vaccum hose..sold by meter..you need 2 meters to do all lines...3mm hose as I recall..bought that at my local dealer.


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## FrankB4now (Dec 28, 2008)

*Re: 2003 Passat 2.8l 6cyl with misfires and misc. DTC codes??? (spitpilot)*

Hey SpitPilot, thanks for the feedback, I will check through the lines in the new year. That could explain those codes. Could the misfire problem cause that to surface. I was thinking the, Warm Up Catalyst: Bank 2: Efficiency Below Threshold code could be caused by the unburnt gas from the misfires. I still don't have any idea what to try next on the misfire problem, that is the main cause of the MIL light, these other codes are just coming up randomly. Do I start looking into the injectors next and how do you troubleshoot them? Happy New Year!!


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## Slimjimmn (Apr 8, 2006)

*Re: 2003 Passat 2.8l 6cyl with misfires and misc. DTC codes??? (FrankB4now)*

does your secondary air pump run when you start the car?


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