Need serious help fixing my lemon

[Deserthawk]

Hey guys, need some serious assistance please. My car is throwing consistent codes and no matter what I replace I can't get rid of them
The car is a 2004 A4 Avant quattro 1.8t USP

Here are the issues

Check engine keeps coming on for these codes
16523 - Oxygen (Lambda) Sensor B1 S2: Response too Slow

P0139 - 004 - No Signal/Communication - Intermittent

16524 - Oxygen (Lambda) Sensor B1 S2: No Activity

P0140 - 004 - No Signal/Communication - Intermittent

17522 - Oxygen (Lambda) Sensor; B1 S2: Internal Resistance too High

P1114 - 008 - Implausible Signal - Intermittent

16395 - Bank 1: Camshaft A (Intake): Retard Setpoint not Reached
(Over-Advanced)

P0011 - 002 - Lower Limit Exceeded - Intermittent

Biggest problem is no matter what it won't keep time and it's throwing a fit over O2 sensors, both of which have been replaced. Matter of fact here's a list of what's been replaced recently. Some are related some aren't who knows.

New head (old one was cracked when I bought it which had it's own host of issues with misfires-Solved)
Timing belt full kit including water pump, tensioner, belt etc
Thermostat
Timing chain tensioner (replaced twice, first replacement failed)
Oil pump and pickup
Turbo
APR diverter valve
both o2 sensors
catalytic converter (with aftermarket cat from ECS tuning)
coil packs
New fan control module and main fan
Freshly serviced AC
2.5 inch down pipe

This car has been an absolute nightmare, the check engine light hasn't been off since the night I drove it home. I regret taking it home but the wife still loves it and it's gonna be the baby wagon next month so it needs to be fixed.

[redline380]

I'd look at the timing, both belt and cams, as well as the ECU possibly. Who was doing the labor on the car?

[Deserthawk]

247 Auto here in El Paso did the initial work. Vag Haus checked the timing over and over afterwards. I've replaced the valve cover gasket about 6 times now each time they checked timing. Verified correct # of links between the 2 cams.

[Deserthawk]

How do you check ecu?

[00passat]

What brand timing chain tensioner did you use? Did you use the oem like oxygen sensor that plug and play if so what brand? Was this a problem before the head was changed as well or after?

[Toronto5.5]

Maybe buy a used AMB, swap it in and part out the current shitty one? You can swap all your new parts onto it, so the money won't go to waste.

How good are you at

[Deserthawk]

Oxygen sensors were replaced with the Bosch oem replacements.
The timing chain tensioner is one off eBay with the Audi logos on it. Supposedly oem. Firs tensioner replacement failed after 1k miles so I swapped oil pump. Good thing too cause the pickup was pretty clogged with junk. I'm fine at the work. I can replace the engine but I'm already way too much money into this car. Don't want to part it or sell it but I'm almost there if I can't figure this out. It also isn't putting out heat to slap me in the face some more. But that's a different issue

[Toolaa]

I think it's important to note that all of your O2 sensor errors are from the rear sensor which does not impact air/fuel ratio. The only thing the post-cat sensor does is monitor the efficiency if the CAT. Unless the pre-cat sensor fails and then the ECU will use the post-cat to adjust fuel trims. I think these codes are totally unrelated to the P0011 - 002 - Lower Limit Exceeded - Intermittent

For the P0011 it sure does point to the Cam Adjuster but it could be related to the wiring to the solenoid or even low oil pressure which is keeping the adjuster from advancing the timing in the manor that the ECU is expecting. Do you ever get any oil pressure warning lights?

There is a test procedure in VCDS to check the Cam adjuster solenoid. I think it's block 094 under basic settings.



Sent from my iPhone using Tapatalk

[Deserthawk]

Never had a low oil pressure light. I'll give that block a try right now if I can figure it out. I'll post back in a few with results

[Deserthawk]

First block says 800/min
Second says cam ctrl.ON
3rd says test off

[Deserthawk]

Just remembered something. I wasn't getting all these o2 sensor codes before my friend put in a 034 motorsports o2 sensor spacer. The reason he said to out that on was because the previous code it was getting was catalyst efficiency low. Do you think the codes I'm getting now are because it's not spaced out properly?
I would rather focus on the timing issue first but since I remembered we did that I figured id put the info up.

[00passat]

Will defiantly get these codes with a spacer:
16523 - Oxygen (Lambda) Sensor B1 S2: Response too Slow


16524 - Oxygen (Lambda) Sensor B1 S2: No Activity

I dont think this code will come from the spacer:
17522 - Oxygen (Lambda) Sensor; B1 S2: Internal Resistance too High

[Deserthawk]

Awesome that helps thank you. Maybe I'll try getting another new sensor. Is the pre cat sensor same part number as post cat?
Now just need to figure out the timing issue

[00passat]

No they are very different sensors.

[LINDW4LL]

Ignore the rear o2 codes for now as they don't affect how the car runs.

Here are the possible causes for your timing code:

-Camshaft Adjustment Valve 1 (N205) faulty
-Fuel Pump Relay (J17) faulty (I don't think this is your issue)
-Mechanical Timing not correct, including Chain and/or Belt timing.

[Deserthawk]

I didn't even know there was a cam adjustment valve. So even if it's not throwing a code for that valve it could be bad? Where is it located?

[CyberPMG]

Just remembered something. I wasn't getting all these o2 sensor codes before my friend put in a 034 motorsports o2 sensor spacer. The reason he said to out that on was because the previous code it was getting was catalyst efficiency low. Do you think the codes I'm getting now are because it's not spaced out properly?
I would rather focus on the timing issue first but since I remembered we did that I figured id put the info up.

Take the spacer out. It's not needed if you're running with a OEM catalytic converter. Only time you may need the spacer is if you are using a high flow catalytic converter or a test pipe. Clear out the codes, and then try again.

[alexza4]

I think these are VVT issues. I would double check everything even though you're saying you've replaced the chain tensioner. It sounds like your timing may be off a bit

[Deserthawk]

Not running an oem cat. It's an aftermarket which I think is why I got catalyst effiecency low.
I'll check timing for like 8th time lol. Is there a vcds block that will tell me if timing is off?

[Charles.waite]

the " No Signal/Communication - Intermittent" part of those codes makes me think it could be bad wiring or a bad relay somewhere in the ECU box or the engine bay. I would try pulling the ECU and confirming if there is water/rust/corrosion on any of the relays under the ECU.

You also might want to inspect the chassis grounds in the engine bay and make sure they're clean an corrosion free. If the grounds are dirty and not making a good circuit, they can throw all sorts of phantom codes.

If the timing has been verified repeatedly, thats unlikely to be the issue, I wouldn't bother checking and rechecking the timing, its not going to change, you're just throwing money down the drain..

[Deserthawk]

Grounds is a good idea. Does anyone happen to know where they all are? Ive also replaced the engine wiring harness btw. Forgot to mention that as well. This car has had issues for a long time, lots of part swapping has gone on. (didn't fix the issue)

[Charles.waite]

One is off the battery negative terminal, one is down by the starter I think. Can't recall the third.

[Deserthawk]

Ok I'll poke around and see what I can do. Doubt this will fix it but worth a shot

[diagnosticator]

Ok I'll poke around and see what I can do. Doubt this will fix it but worth a shot

Are the same DTCs occurring after replacing the engine wiring harness compared to before? BTW, there are no used lemon Audis.

[LINDW4LL]

I didn't even know there was a cam adjustment valve. So even if it's not throwing a code for that valve it could be bad? Where is it located?

The list I posted is the possible causes from Ross-Tech's website. The N205 valve is actually only a term used for the 2.0T engine, but it refers to the cam tensioner assembly on the 1.8T. Very weird since you already replaced it. It could technically be a wiring issue to the cam tensioner I suppose.

How does the car drive? If the timing is perfect, the car should drive 100% regardless of the codes you are throwing.

[Deserthawk]

Ok good to know I couldn't find any info on an N205. But yeah the cam chain tensioner was replaced and the car drives fine until the check engine light comes on. it becomes a little sluggish. Same codes are popping up after the wire harness change. I'm gonna advance the timing one tooth on the intake cam this weekend to see if that makes it happy. It seems to only trigger the CEL when I get on it. If I just put around and never get up high in the rpm range it takes a long time to pop the CEL.

[diagnosticator]

Ok good to know I couldn't find any info on an N205. But yeah the cam chain tensioner was replaced and the car drives fine until the check engine light comes on. it becomes a little sluggish. Same codes are popping up after the wire harness change. I'm gonna advance the timing one tooth on the intake cam this weekend to see if that makes it happy. It seems to only trigger the CEL when I get on it. If I just put around and never get up high in the rpm range it takes a long time to pop the CEL.

Interested in the results of moving the cam sprocket one tooth in the advanced direction, (counter clockwise,).. BTW, the part is not a timing chain tensioner, it's only purpose is to vary the intake cam timing with relation to the exhaust cam and crankshaft angular positions.