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Discussion Starter · #1 · (Edited)
CEL, codes P0171 and P1136 - diagnosis?

CEL is solid, not blinking. Just popped on this morning after I was up to temp, didn't blink at all...solid right away. Cannot dig around in engine bay while at work, during lunch Bob at LOTR (Dallas indy) ran VAG-COM and those codes popped up.

P0171 - System Too Lean
P0303 - Cylinder 3: Misfire Detected
P1136 - System Too Lean

Original vac lines, after searching I am guessing the L-hose behind manifold is the culprit:
http://www.passatworld.com/forums/4...ure-control-valve-replacement.html#post820906, and
http://www.passatworld.com/forums/4...ussion/196049-engine-misfire.html#post1184076

Further down in 2nd thread it's mentioned that ICM issue is usually Cylinder 2, since mine is Cylinder 3 hopefully it's just that L-hose. Tech at LOTR did not see any immediately noticeable probs, vac lines look OK - but couldn't check the L-hose on a hot engine given proximity to manifold.

Thoughts on any other potential culprits? TIA

Btw, kicking myself...just the other day I said "you should buy one of those $15 VAG COM cables off ebay". Bob charged for hooking it up and running codes, but he has helped me diagnose a few other issues without pay before - so I'm fairly OK with it. Next time heading to AutoZone, though. :p
 

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Discussion Starter · #3 ·
Past couple mornings have been odd. RPMs on startup are normally above 1,000 especially in the cold, then I'd wait for them to drop to about 800 or so before heading out (quick warm-up).

Since the CEL has been on, cold start hangs around 800 RPM. Is this a result of the vacuum leak? Still haven't had a chance to inspect the L-hose, it's dark when I leave in the morning and dark when I get off work. :(
 

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Discussion Starter · #5 ·
Light back on this morning. :( Never checked the L-hose, get to do that tomorrow morning - boardwalk VW stealer in Richardson is open xmas eve, surprisingly.

Inspection is past due, but I am going on a trip next week and won't be back until 2012. Hopefully it's the L-hose or the CEL goes off again so I can get that done. :)
 

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Discussion Starter · #8 · (Edited)
Welp, is this the L hose that is common culprit for these 2 codes? Haven't removed, but felt around and there isn't an obvious split that I feel on the bottom. Top looks fine.



Anything else that could be the cause here? Should I wrestle off those one-time clamps to inspect?

The ends don't really look like this dude's, is that just from the clamps or am I looking in the wrong place here?
 

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Discussion Starter · #10 ·
CEL went off next start after tinkering with that L-hose and a couple of the check-valves. Looks like last original check valve I haven't replaced is in the vicinity, would that throw the CEL?

None of the other ones did...didn't check for too much play on this one b/c I didn't want last original to break it if it wasn't already busted. Damn things get crazy brittle.
 

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Discussion Starter · #11 ·
Man this is frustrating. Mostly b/c my inspection is past due and car won't pass until I figure this out. Really don't want to take it somewhere, at this point I am guessing it's just a regular vac line - L hose appears in tact and I checked all one-way valves, etc.

Just for my future reference since I'm out of time today:
http://www.passatworld.com/forums/4...46-please-help-find-4-th-vacuum-hose-awm.html
http://www.passatworld.com/forums/6...38-diy-how-replace-1-8t-awm-vacuum-hoses.html
http://www.passatworld.com/forums/4...3294-b5-5-awm-vacuum-diagram.html#post2682956
SVH™ By the Foot : HoseTechniques Silicone Turbo Hose, Buy Direct from Manufacturer, Best Quality / Best Price - Hose Techniques established 1983 - Quality, Performance, Style
 

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Discussion Starter · #12 · (Edited)
All the vac lines feel decent - ones underneath the intake look like a bitch to replace, too. Surprised, everyone mentions they're braided lines...mine are rubber, think I saw somewhere that 2003 was year they switched. Used this thread to locate: http://www.passatworld.com/forums/6...38-diy-how-replace-1-8t-awm-vacuum-hoses.html

Is this the end of bottom one that runs length of the engine then goes underneath to DV? Just inside the passenger wheel?



If so, mods may want to put pic in the thread.
 

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Discussion Starter · #14 ·
Thanks. No hand vac pump handy, I live in an apartment. :p

Can't view pic from work, any chance whatever that is came loose and is causing CEL? Presumed only the vac line could cause lean code so I did not bother past confirming it was connected and line looks OK.
 

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Discussion Starter · #15 ·
Quick question: Does the fact that CEL is intermittent point to any particular area in the vac system? Seems if it were a gaping hole somewhere CEL would be constant, probably just a small leak/clog somewhere.
 

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Discussion Starter · #18 ·
Have you tried swapping the coilpacks around to see if the misfire code moves with the coil or stays with the cylinder?
Believe a misfire did not show up on OBDII printout from botched inspection - just the lean codes. Will double-check at lunch break and update.

It'd be good to see what your learned fuel trims are. If the Additive value is way off, look for something leaking manifold vacuum. If the multiplicative value is way off, the MAF may be contaminated or bad.
Fuel efficiency itself is actually fine - this fill-up was better than previous. 24.484/gal most recent tank, prior was 23.869. Have an app that tracks it.

Presumed if the fuel trims were off I'd be getting worse mileage? I did more hwy driving on recent tank so not terribly surprising, but it was still mixed w/ plenty city. Just happened to be going further distances within Dallas than usual.

Doyles, try pinching the hose that connects to the intake mani right under the L Hose. It goes to the PCV. If the PCV or "bleeder valve" plunger dislodges internally, you will get on and off CEL as sometimes it makes a seal and other times not. Do you hear anything hissing while running and listening under the hood?

03+ got the nice almost indestructable rubber lines. 125K and they still look new to me.
Will do next chance I get. Don't recall any obvious hissing, would have focused on that area if so.

And yeah, vac lines look fine - which is actually kinda disappointing, I was hoping swapping them would be the fix. :p Opted out after inspecting, hope they last to 250k! (personal target for the car)
 

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Discussion Starter · #20 · (Edited)
Interesting. Bought a cheapo VAG-COM cable b/c of all this that I have yet to try out, hopefully software can advise fuel trims?

FYI, scan on 12/5/11 thread start was probably the first since previous inspection 14 months ago - no misfire in the recent 1/24/12 scan. 1,521 miles clocked between them...misfire was probably unrelated. Here are updated codes from 1/24/12 scan:


17544 P1136 001
Bank1, mixture adaptation (add)
System Too Lean
static

16555 P0171 004 -- note this was on first scan too, forgot to include in OP
Fuel Trim, Bank1
System Too Lean
static

16891 P0507 001
Idle Control System
RPM Higher Than Expected
intermittent


CEL went off again last night, still off on my drive to work this morning.

If VAGguy's PCV bleeder valve test yields nothing I may see if PZ can take a look, seems this is getting over my head...no clue why CEL is intermittent. Hope it's nothing blatantly obvious, not sure my pride could handle that. :(
 

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Discussion Starter · #21 · (Edited)

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Discussion Starter · #25 · (Edited)
Replied to your PM. A MAF flow test is also a good idea. If your system can't run one, mine can (I just have to figure out how!). When I had my 1.8T, my P1136 was from a bad MAF.

If you need to swing by this weekend, give me a call. PM if you don't have my #.
Thanks Paul. Was down in Houston this past weekend (in someone else's car). Gone again this upcoming weekend to Austin - any chance you have time throughout the week (if yours does MAF flow test)? Still haven't hooked my cable up, no clue what its capabilities/limitations are.

Pretty sure I am going to replace key PCV parts regardless of MAF status. When researching I saw way too many threads of 1.8's with a lot less miles having clogged PCV.

Right. If my pcv goes, I'm getting the kit from 034 and doing it all. Same for my amb a4.
I'm iffy on 034, solely b/c of the extra line going to back of valve cover it doesn't seem to support on 03+ AWM.
 

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Discussion Starter · #26 ·
PCV is definitely the culprit, #2 in below diagram is busted where it enters T housing - breather hose and T are completely separated:



Unfortunately I couldn't get the one-time clamps off before I had to abort given amt of daylight left. While trying from above with a long flat-head, I busted the only check valve that has a 3rd prong - right above suction jet pump. Even though I ordered a couple of back-up check valves...broke the only unique one. :( VW gods shat on me.

Since I'm replacing 2, 5, 6A and 10...I could put that whole line together before installing, then I'd only have 2 clamps to tighten. Which means it's only those 2 clamps I have to remove.

Any advice on strategy/angle to remove clamps from right side of T housing and bleeder valve (6A leading to 27) would be much appreciated. Fu#$ me if I have gotten this far and still have to pay a shop. Soonest I can try again is next Sunday.
 

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Discussion Starter · #27 ·
Well hell, I finally got clamp off #5 but can't get that t-housing itself off #9. :( So frustrating. Guess I'll have to take it somewhere and see if they'll only uninstall 2 & 5 for me, let me do the rest. Really hate paying someone to just connect everything past that.

If only I had a dremel, would just cut through 5 and be done within couple hours at most. :banghead:
 

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Discussion Starter · #29 · (Edited)
Yeah, knew that from replacing check valves previously. Much tougher on something that's beneath the manifold with extremely limited space for leverage, I used a very short flat-head and eventually finagled an angle where I could put force behind it. Cut my hands up pretty decently, finally removed clamp...only to find out the t-housing is basically melted to the pipe it's connected to. :(

Considered buying a dremel, but honestly I'm not quite sure how #2 is removed anyways...probably best to have someone who's done it before handle. Left PZ a voicemail.

Edit: PZ indicates razor blade should do the trick on that rubber T housing, think I'll try box cutter - one more DIY attempt next weekend! Also, the retaining spring that holds #2 in place is apparently very similar to the CTS clip.

Also, tip for others - if replacing at least 2, 5 & 6A...the only clamp you have to fret over is right side of #5 (T housing). For the other line coming off PCV valve going to 24, much easier to just remove top clamp on that first section of breather hose where it meets check valve (instead of trying to get bottom clamp off where it connects to PCV valve). Easily accessed from above, suggest having a replacement check valve on hand if it's original one.
 

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Discussion Starter · #30 ·
Really hate my car atm. Couldn't get the retaining spring off #2, so I didn't even bother trying to cut out the T-housing. Tried with a few different pairs of pliers, kept slipping off. Hopefully PZ to the rescue, so pissed I have to pay someone else to do this after 6+ hours of my time was wasted. :(
 
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