jenkins214

Hi all,

I have a 2001 Avant (2.8) ATQ with 185k miles. I recently started to develop some cam chain tensioner noise (like a diesel sounds) and just for confirmation asked a great local shop for a diagnosis. They agreed that the bank 2 CCT needed to be replaced. I ordered a supposedly quality OEM adjuster for $350. It is a new unit not a reman. I replaced it the other day and everything went well until I started it. Car was running rough so I plugged in my Vag Com and checked for codes. Code 17938 - Camshaft Timing Adjustment - Short to ground? This had me baffled. I checked the pins on the plug, all good. After some research it sounds like the Adjuster might be bad? I did run the engine output test from the Vag Com. Initially the adjusters did nothing, so I unplugged the new one (bank 2) and bank 1 started to cycle away. If I plug Bank 2 back in they will not cycle. I tried to hook a meter up to the plug (for bank 2) during a test to read for power and it will create the same result, neither works? Not sure I understand that. At any rate with the car idling the bank 2 plug reads 12+ volts steady on the brown/yellow (top) wire. I think the bottom wire is grounded per the ECU?

When the car is running and the new bank 2 adjuster is plugged in I get multiple misfires and the ground codes. If I unplug it, no misfires or codes.

Questions:

1. Do I have a bad Cam Chain Tensioner?
2. Is there any other test I can do to verify it is faulty?

Thanks, I just hate to go through the trouble of pulling it out, swapping in a OE Audi for $800 and finding the same issues somehow.

Rick

SloopJohnB@mac.com

Electrical test of solenoid valve for camshaft adjustment
Cylinder bank 2 (left)

Remove cover - 1 - in engine compartment (left side).

Remove coolant reservoir (arrow)

Remove line from Engine Coolant Level (ECL) warning switch F66 and lay coolant reservoir to side.

Note:

Coolant hoses 1 to 3 remain connected.

Cylinder bank 1 (right)

Remove cover - 1 - in engine compartment (right side).

Remove bolts (arrows).

Remove air guide - 1 - .

Disconnect Evaporative Emission (EVAP) canister purge regulator valve N80 - 1 - at air filter housing.

Remove air filter housing (arrows).

Continuation for both cylinder banks

Disconnect harness connector (arrow) from connector-adapter.

Sorry about no illustrations…ebahn is about impossible other than a screen shot and upload.
The above steps are basically to get to the harness for the camshaft adjuster.
BTW…I don't think the 2.8 doesn't control cam chain timing with a CCT like on the 4.2.
The CA is a rotary adjuster.

Note:

Illustration depicts cylinder bank 2 (left).
Checking internal resistance
Valve for camshaft adjustment (intake)

Connect multimeter between terminals 1 and 2 for resistance measurement.

Specification: 7.4 to 8.2 Ω

Valve for camshaft adjustment (exhaust)

Connect multimeter between terminal 2 and 3 for resistance measurement.

Specification: 12.8 to 14.2 Ω

All

If specified value is not obtained:

Replace valve.

If specified value is obtained:
Checking voltage supply Requirement
Fuse for valves for camshaft adjustment OK. Electrical Wiring Diagrams, Troubleshooting and Component Locations

Connect voltage tester VAG1527B as follows:

Harness connector Terminal Measure to
2 Engine Ground (GND)
Switch ignition on.

LED must light up.

If LED does not light up:

Check wire connection from terminal 2 of connector via fuse to Motronic Engine Control Module (ECM) power supply relay J271 for open circuit: Electrical Wiring Diagrams, Troubleshooting and Component Locations

Repair open circuit if necessary.

If LED lights up:
Checking activation

Connect voltage tester VAG1527B as follows:

Valve for camshaft adjustment Harness connector Terminal
Intake bank 1, Valve -1- for camshaft adjustment N205 1 + 2
Intake bank 2, Valve -2- for camshaft adjustment N208 1 + 2
Exhaust bank 1, Camshaft Adjustment Valve 1 (exhaust) N318 2 + 3
Bank 2, Camshaft Adjustment Valve 1 (exhaust) N319 2 + 3
Initiate output Diagnostic Test Mode (DTM) and activate valve for camshaft adjustment.

LED must blink.

If LED does not blink or if it remains constantly lit:

Connect test box VAG1598/31 to harness connectors of wiring harness (do not connect ECM). Connect Ground (GND) clip at test box (not visible in illustration) to Ground (GND). 3.0 Liter V6 5V Fuel Injection Ignition, Engine Code(s): AVK - Repair Group 24

Check following wire connections for open circuit and short circuit to Ground (GND) and B+:

Valve for camshaft adjustment Harness connector Terminal Test box VAG1598/31 Socket
Intake bank 1, Valve -1- for camshaft adjustment N205 1 115
Intake bank 2, Valve -2- for camshaft adjustment N208 1 120
Exhaust bank 1, Camshaft Adjustment Valve 1 (exhaust) N318 1 22
Bank 2, Camshaft Adjustment Valve 1 (exhaust) N319 1 18
Repair short circuit to Ground (GND) connection or open circuit if necessary.

If wire connection is OK:

Replace Engine Control Module (ECM).

If no malfunctions are detected:

Replace mechanical camshaft adjuster i.e. camshafts, removing and installing, Camshafts and camshaft adjusters, removing and installing .

Copyright © 2006 Audi of America, Inc. and Bentley Publishers. All rights reserved. Last processed:

Prospeeder

No it sounds like the adjuster has a bad solenoid, the winding inside touching ground. Try another one. I have used the cheaper versions with good luck.

With your ohm meter check if either terminal on the adjuster has continuity to ground.

jenkins214

Thanks so much SloopJohnB, not sure I follow the directions completely. Where in the Ebahn reader did you find those? I have the Bentley manual (albeit an older version 2009) and don't see those directions. The Adjuster looks identical to the ones used in the 2.7 and 4.2. I will keep reading what you posted and see if I can get it. Could I not just test the resistance across the solenoid?

And thanks Prospeeder, I will check for continuity as well.

jenkins214

Update: both pins of the solenoid for the tensioner are grounded.

Could I put the solenoid from my older tensioner on the new one? or would that be unwise.

SloopJohnB@mac.com

And it looks like it sent me to a 3.0 page although the page doesn't say 3.0. I looked back a few pages and the 3.0 used those C-shaped camshaft holders for timing belt replacement,

I looked at the valve train mechanical assembly for the 2.8 and it indeed does use a cam chain tensioner to vary timing between the belt-driven exhaust cam and the chain-driven intake cam.

As for swapping the solenoid; it depends on whether it meets the electrical criteria, not grounded, proper resistance, and not least operation. I've not tried to swap the solenoid but if that was the problem on the old tensioner, probably not a good idea. Can you return the 350$ tensioner?

jenkins214

Thanks,

My other tensioner is the original Audi part. I believe the tensioner itself was starting to fail, I am not sure what part if any the solenoid played in that. It test fine for continuity but its an unknown. I was just getting excited at the thought of not having to do it all over again.

I can return the $350 tension and if that is the course I go then it an original Audi part from the dealership for me.

SloopJohnB@mac.com

just the nylon bits needed to be replaced. At 185K miles chances are they're pretty worn. The pistons on the tensioner only go out so far. New tensioner shoes are the same as the 1.8 4cyl, used on the 4.2 V8s as well as the sixes. If you have the tensioner out it's a snap to put on new shoes.

Got a pic of the old tensioner shoes?

jenkins214

The shoes were a little worn but not terrible. There was certainly something else wrong with that tensioner, so much so that it caused a low oil pressure problem. It appeared that the pistons were not extending out at all, or much. I think I am just going to replace the whole unit.

SloopJohnB@mac.com

I've been in the dealership so many times, bought two from them, had the cars repaired there a few times, I can sometimes get quite a discount from book.