Engine Code P0018
 

Hello all,

My engine light is on and I have code P0018 - 001 - Incorrect Correlation. at this time I don't have any other codes for the engine. It does idle a little rough at times and runs smooth above idle. I'm wondering what sets this code off is it the main chain tensioner, and guides or could it be left or right or both cam chain tensioners and guides?

I started the engine and had the occasional tensioner rattle but this time followed by the sound of something rubbing up against a chain. shut the engine off and restarted the noise wasn't there anymore and then the check engine light came on. I was wondering if cam chains, tensioners, or guides could be the cause, and if so could they be changed in the car if needed?



2007 A8L,
4.2 BVJ
213,000+ miles

Something at fault with the timing gear. Could be just needs an oil change, bad sensor, stuck adjuster, all the way up to a failed tensioner, stretched chain, and an engine out job to fix.

Good luck.

https://youtu.be/WXpN2bFmYFI

So I swapped out the intake solenoids with no change. Took some pics of measuring blocks, the pic with the place positions has phase position bank 2 intakes with nothing in the block. this would be an issue with the left (Drives side) chain, guides, and chain adjusters. shouldn't be the main chain, guides, and chain adjuster.

What would cause phase position bank 2 intake to be blank?


https://cimg3.ibsrv.net/gimg/www.aud...c06f9c404d.jpg
https://cimg4.ibsrv.net/gimg/www.aud...fde53161e2.jpg
https://cimg5.ibsrv.net/gimg/www.aud...570003640f.jpg

Bad bank 2 intake cam position sensor? Try swapping out that cam sensor with a known hood one from the other bank, see if the fault moves with it.

Well, it's something with chain timing. It must have jumped a little more now all kinds of miss fires flashing lights. cut the cats out and send it to the salvage yard.

If it’s now jumped timing then it’s probably mechanically totaled.

did you figure this out? I have the same exact issue with phase position bank 2 being blank. I have replaced both cam sensors with brand new audi ones and nothing changed. I wondering if a fuse are a harness issue is what is causing it since vcds is blank. I also cant get rid of the DTC P0018 code. I delete it and it always comes back after I start the car. Only issue I have is a rough idle but the car drives perfectly.

I removed both bank 1 and bank 2 cmp sensors and did as the manual states. Check with the harness off, pin 1 to pin 3 and there should be 1.5 ohms max. Also... check for 5 volts across those pins with the ignition on. I have 5 volts on both bank 1 and 2. Now when I check the ohms, bank 1 (passenger which reads in group 93 without any issues) is showing 135ohms. Bank 2 ( drivers) is showing 1.35 KOhms. Bank 2 is the side that is not showing in vcds like the picture above. Would it be safe to assume ECU J623 is at fault?

You have any luck figuring this out?

He did. The fault code was because of skipped timing. Likely because of a stretched timing chain and/or failed tensioners.

Prepare for a similarly catastrophic prognosis in your case too.