2003 VW Passat 2.8L V-6

[billr]

It has an auto trans, FWD, and had the CEL on for some time. The codes set were P2181, P0300, P0303, and P0304. I pulled the spark-plugs to inspect and check compression. The first thing I noticed is that the plugs are way down deep, and that "well" was very full of oil on #1, 3, 5, & 6. The firing-end of the plugs all looked good and clean, maybe even recently changed. Compression-testing was a real kick! All that oil around the plugs ran down into the cylinders, so compression on the oily ones was very high, >300 psi on the first... but it came down steadily as I kept cranking and testing as the excess oil blew out the open plug holes. One of them I checked repeatedly and it settled out at 190. The two non-oily ones (#2 & 4) were 185 and 190 on first pass, but then #4 steadily decreased with each try until it was down to 85. Later I put all the plugs back and ran the engine briefly, then checked #4 again (with all others in); it was back at 190. My conclusion was that compression is probably OK, at about 190 on all. I checked the plugs for firing while they were out and I was cranking for compression, all OK. By the way, these are "super-dooper" two-electrode plugs and they only fire on one electrode at a time; big surprise, huh! Although I would think oil is a pretty good insulator, cleaning it off the four seems to have cured the miss-fire problem. None of the P03xx codes have come back and the engine now runs smooth at all times. First question: how hard is it to change those valve covers, and how likely is it to be successful?. And just out of curiosity, how is miss-fire detected; by listening to the knock sensor?

Now on to the P2181 code, "engine cooling system performance"; that one keeps coming back. The only info I have right now is that "the cooling system has to be checked and topped-off routinely". I don't really know how often or how much is added, but get the impression it is checked frequently but little is added. It may be the frequent checking is in response to the P2181 and fear of over-heating the engine. The other tid-bit I have is that the car has been a money-pit and their regular mechanic is exasperated with it. My impression, after cleaning the plugs and driving it for a bit, is that there is nothing terribly wrong with it; I just need to get to the root of the P2181. The throttle response is a bit squirrley, but I think that is because it is an all-electric system. At this point I was stymied, as I don't have a scan tool and I couldn't even find the ECT sensor or thermostat to even consider checking; and batauto's server crashed. Next question, for Jim F: can you post some pictures of where stuff is located on that engine?
Good news is that this engine is mounted fore-and-aft, so everything is much easier to access that transverse V's I have seen. I have a block test kit and was going to check for combustion gas in the coolant, but my test fluid had turned to yellow over the years; I'll have to do that next session. At this point I am open to any hints or suggestions, but feel I have to get a real scan-tool to go much further. I'll post in "Auto Products" about that.

 

[nickb2]

Hey bill, how you doin'!? Might want to change those spark plug wires and boots as the oil in the plug tubes will have deteriorated the synthetic rubber insulation causing futur misfires arcing to ground within the tubes through the rotted boots. As for the valve covers, they are really quite easy to remove once all that decorative crap is removed from engine surface. You may also want to replace the coolant sensor as they are notoriously a problem for VW. This is basically an audi engine which is tuned down from 3.2l to 2.8l. These are inverted coolant systems, make sure all cooling system is clean and in good order. Again, check into a new coolant sensor. Just be glad you are not changing a oil pan or timing belt on this fu%king engine. They are hell for the DIY. Need special tools all over the place. The oil pan needs a 6inch long 5mm allen socket. Where do you buy that? Only snap, mac or SK seems to sell em. Another problem location for these 2.8l is the cam sensor oil ring leaks oil onto the timing belt and scraps it in the process. Check it out on the driver side near front of engine behind cam shaft backing plate. Should see the cam sensor there and look at base to see for oil leakage. Be sure to have a good set of allen sockets or grind the used ones down that you have if they are chipped. I use compressed air on all the bolt heads to make sure all the crap is out before setting a socket in before rounding out those allen bolt heads. They are everywhere on this engine. Will need 5mm,6mm, and 1/4inch for the 6mm allen drive if it's rounded. I use "the right stuff" when bolting back on those valve covers in the cam shaft seal crevices. Permatex makes that stuff. Awesome sh%t!! Well worth the extra $$. Have fun with that project. See ya and yes ethanol is cool and ok to use. A 10% mix is acceptable in a non-flex fuel engine.

 

[billr]

Oh. oh... you said "timing belt" Nick, is this an interference engine? I don't know right now, but I expect it has over 100K miles on it (and the seven years). I might be able to find out whether it has ever been changed, but that info is probably not available. Too bad it takes all those special tools, the front of this engine looks pretty easy to get to! If you are familiar with these cars, where are the ECT, thermostat, and fuse/relay panel(s)? I couldn't find any of them... have asked Jim F. to post pix, but maybe you know. Plug wires and boots look OK, no sign of softening from oil-exposure. Over-all this engine doesn't seem to be a leaker, just down in the plug wells. Those are part of the valve covers, right, not separate tubes sealed top-and-bottom?

 

[nickb2]

1. Find the following tools=
T-20 Torx socket
T-20 Torx screwdriver
T-25 Torx socket
T-30 Torx socket
T-45 Torx socket
Phillips head screwdriver
10mm socket
13mm socket with extension
17mm socket
5mm Allen key
10mm Allen socket
12 inch adjustable wrench or a 32mm wrench
Strap wrench or VW special tool 3212
6mm Allen socket
6mm Allen key
5mm Allen socket
VW Camshaft Pulley puller
24mm 12 point socket, ½”drive
10mm wrench
VW special tool 3242
8mm Allen socket
VW special tool 3391 camshaft clamp
Torque wrench(s).
2. Disconnect battery.
3. Remove plastic bottom engine shield.
4. Remove 3 T-20 Torx head screws holding plastic wheel liner to bumper cover, each side. There are several more Torx screws in the wheel
liner but only these three need removed. (T-20 Socket).
5. Remove T-20 Torx head screw holding plastic wheel liner and bumper cover to fender, each side. (T-20 screwdriver or socket with small
extension).
6. Remove 2 Phillips screws, yellow circles in photo, holding air cleaner intake to the top of the “engine cowl area” and remove two segments of plastic “air intake“.
7. Unclip turn signal lenses.
8. Unplug headlight connections.
9. Remove 10mm bolts holding plastic cover to bumper, located under parking light lens area. 1 each side. .
10. Remove 2 phillips head screws holding black rubber “hold-downs” to top of bumper cover. Located front, top, middle(one general location,
not three different areas) normally hidden by car hood of car. Indicated inside the square in the photo.
11. Remove 3 T-25 Torx screws from front of hood lock area.
12. Remove hood-release lever from hood lock. Hint: With small flat-head screwdriver gently pry retaining clip off of pin that holds the plastic
release lever to the lock mechanism. Using snap ring pliers (even though there is no snap ring), spread the two arms of the release lever apart and off of the pin on the release mechanism.
13. Remove bumper cover. Work gently- - work from side to side trying to pull the cover straight.
14. Remove bumper carrier using 13mm socket and extension.
15. Remove bumper guides using T-25 Torx socket and extension. Remove 2 or 3( I had 2 but Bentley shows 3) screws from each bumper guide.
(Looking from directly in front of each headlight, the screws are below the headlight facing you). Use screwdriver to gently pry bumper guide plastic retaining clips(actually part of bumper guide, built-in if you will) from fender (2 each side).
16. Remove air temperature sensor from the bracket connected to the power steering cooler lines. Remove the retaining clip holding the air
temperature sensor line to the front of the radiator. Feed air temperature sensor wiring to the rear of the radiator up into the engine compartment.
17. Remove power steering cooler line from the front of the AC radiator by removing the 2 bolts using 10mm socket with extension. I moved it
under the engine and gently hooked it out of the way on the lower engine protector support.
18. Remove 3 10mm bolts holding hood-release lock mechanism to lock carrier.. Move the hood release lock mechanism out of your way. Hood
release cable does not have to be removed from hood release lock mechanism.
19. Remove coolant reservoir filler cap. Open radiator drain. Some suggest replacing the drain and gaskets with new.
20. Pull up upper coolant hose retainer clip (do not remove). Remove upper coolant hose from radiator.
21. Unplug electrical connection to radiator fan thermo switch from lower coolant hose. Do not unplug the plastic horseshoe clip that holds the
thermo switch into the radiator hose. Pull up lower coolant hose retainer (do not remove). Remove lower coolant hose from radiator
22. Reinstall the coolant reservoir cap.
23. Close radiator drain.
24. Unplug wire that runs from engine side of radiator on the passenger side. It connects to a connector emanating from above the oil pan to the
rear of the alternator. Plastic cable tie may hold this line with another wire to the oil pan. If so, cut cable tie. Be careful not to cut black
shielded wires.
25. Remove black cover located to the right of the oil filler cap, left of power steering reservoir, front of ABS box, and rear of the driver’s side
headlight.
26. From the “wiring harness” located underneath this black cover, unplug the connectors that have wires leading up to the area between the viscous
fan and electric AC fan. It is necessary to also make sure these wires do not get caught or tangled in anything when you initiate step 30 below.
27. Remove 2 Torx T-30, 1 each side holding lock carrier to bracket that attaches to front frame that supports fenders.
28. Remove T-30 Torx screws (1 each side) from top of front-end assembly where it meets the inner fender hood area.
29. Using T-45 socket, remove bolts holding lock carrier to front end frame. 4 on the passenger side, 3 on the driver’s side. We are now
ready to remove, not just pull lock carrier into service position. you can insert the two bolts that attach the inner bumper support into the two holes designed for the VW special tool
3369. The extra room and view prove more than helpful in working on the pulleys and belts.
30. CAUTION!!!! As you are doing the following step, make sure you have a good grip on the lock carrier/radiator section and make sure
you have a support ready on which to set the lock carrier/radiator.Slowly pull lock carrier/radiator section forward a
couple of inches off of the frame and engine snub and swing the driver side outward like a door with hinges on the passenger side. There is no hinge on the left side and there are still hoses and wires connected to the left side. Be careful not to disconnect them or damage them. Support the lock carrier in a very, very upright position. You do not want it to fall backward or forward or downward. I used a board to not let it fall backward.
31. Remove top three sections of black engine cover.
32. Using 17mm socket, turn accessory belt tensioner bolt clockwise to release tension. While tension is relieved, still holding pressure clockwise,
insert a 5 mm Allen wrench (or other suitable device to use as a pin) through the holes that will line up at the top left of tensioner.
33. Remove accessory belt tensioner using 10mm Allen socket. Keep retaining pin in postion. Do not remove it and relieve the tension. You
need it in this position to reinstall.
34. Remove accessory belt.
35. Remove viscous fan. I used a 12 inch adjustable wrench for the fan nut (32mm), which is turned clockwise to loosen. I used a strap wrench to
grasp the viscous fan pulley in lieu of using VW special tool 3212 spanner.
36. Remove fan retainer using 6mm Allen socket , 6mm Allen key, and 5mm Allen socket on the bolt partially hidden by fan pulley, depending
upon position of pulley..
37. Remove upper three timing belt covers by unclipping. Passenger side, middle, and driver side. The middle one may take some wiggling and careful, gentle cajoling—kind of like a puzzle.
38. NOTE: I have a five speed manual transmission. It needs to be in neutral with parking brake engaged. I don’t know what difference an
automatic transmission makes. Use a 24 mm 12 pt socket to turn the crankshaft pulley/vibration damper clockwise to line up timing marks on lower timing belt shield and crankshaft pulley. The mark on the crankshaft pulley is a vertical line stamped into its edge. There is an arrow on the plastic timing belt shield.
39. There are two holes in each camshaft pulley, one larger than the other. All four holes should be on a straight horizontal line at this point. The
larger two holes need to be towards the inside of the engine. If the larger holes are towards the outside of each pulley (towards the fenders), turn
the crankshaft pulley until the larger holes of the camshaft pulleys are on the inside position of each pulley in a linear position.
40. Remove 8 bolts holding crankshaft pulley/vibration damper using 6mm Allen socket.
41. Remove two bolts holding lower timing belt shield, which is located behind the crankshaft pulley you just removed. Use 10 mm socket.
42. Remove 10mm bolt from sealing plug located in lower driver side of cylinder block on the under side of the block to the rear of the AC compressor. Remove sealing plug and o-ring. You have to work in a small area doing this. I used a 10mm wrench. Thread in VW tool 3242 clamping tool. This makes sure the crankshaft doesn’t move while you’re working on the timing belt and camshaft pulleys. Use a mirror and light to look into the sealing plug hole. The indentation/divot/crater must be visible to ensure you are at TDC(top dead center).
43. Insert 8mm Allen socket into timing belt tensioner and turn socket clockwise to compress tensioning lever until you can insert a holding pin through the silver/chrome piston housing and tensioner piston. I used a 6D finishing nail grinded down, until it fit into the holes.
44. Remove timing belt, note direction of rotation if not installing new timing belt.

:ROFL Ok Bill, ready to take this on? Post back if you want more info!!

 

[Jim Fairbanks]

Here you go Bill...sorry I didn't get it sooner....Jim...Glad to see everyone back...Gee...I missed this site not running...LOL...Hmmmm having trouble posting the pics...it says the file is to large...I will keep trying..

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[billr]

Jim,
Thanks for the pix. I don't have the car right now, but suspected the thermostat was down there someplace once Nick said it is a counter-flow system. I was looking all over the front of the engine for the ECT, so your pic there is what I needed. I forgot to ask before, but how about the fuse/relay panel(s), I couldn't find any; although I was intrigued by the battery buried under the cowl area!

Nick,
All that to change the timing belt??? The tool list doesn't worry me so much, but all the stuff to remove seems a pain. It looked like there was so much room between the engine and radiator I thought it should be simple on this car! I was amused by that little plug and alignment "crater", just like the Model A Ford; except there you could turn the plug around and use it to feel for the crater (on the cam gear, actually).
Is this an interference engine? (Anyone feel free to answer, that's the key issue for me.)

 

[Jim Fairbanks]

The fuse panel is located behind a cover on the driver side end panel of the instrument panel (dashboard)........Jim.

 

[billr]

OK, I finally discovered the "Timing Belt Interval" section on this site... it IS and interference engine. Ugh!

 

[Jim Fairbanks]

That sucks...LOL...Jim

 

[billr]

Is this one of those engines that has two ECT sensors/senders; one for the panel gage and one for the ECM? And Jim, is that "LOL" lots-of-luck, or laughing-out-loud?

 

[Jim Fairbanks]

Hey Bill...it only shows one sensor....sorry...it was laughing...Jim

 

[billr]

Time to get back to this, I have a scan-tool now. The original codes are gone today, but P0421 and P0431 were set (bank 1 and bank 2 cat warm-up efficiency). The first thing I noticed from live-data is the TPS seems bad. It ranges from 14% to 87%, no throttle to full throttle; and it doesn't seem to be linear. However, I think this is an all-electric throttle system, so maybe I am not understanding it correctly. First question: where is the throttle and TPS? I believe that is all at the rear, between the intake runners and firewall; but I only see two solenoids and what I think is the IAT sensor. Also, is there no MAP sensor for this system? My scan-tool shows nothing for MAP, not even a field for it on the screen. The ignition advance seems kind of flaky, at idle it hunts between 5 and 15 deg advance, but that may well be because of the TPS since at idle the "calculated load" is about 30% I figure to fix the TPS, if those reading do indicate bad, then re-group.

 

[Jim Fairbanks]

here you go Bill....hope this helps some...Jim..........

NOTE:
The overview of component locations shows the following components:


EPC indicator lamp for electronic gas activation
Brake light switch -F- and brake pedal switch -F47-
Throttle Position (TP) sensor -G79- and sensor 2 for accelerator pedal position -G185-
1 - 4-pin harness connector

Green
For Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) -G130-, bank 1 and oxygen sensor heater -Z29-, cylinder bank 1
2 - 4-pin harness connector

Brown
For Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131-, bank 2 and heater for oxygen sensor -Z30-, cylinder bank 2
3 - 4-pin harness connector

Black
for Heated Oxygen Sensor (HO2S) -G39-, bank 1 before Three Way Catalytic Converter (TWC) and oxygen sensor heater -Z19-, cylinder bank 1
4 - 3-way connector

Brown
for Knock Sensor (KS) 1 -G61-, cylinder bank 1
5 - Engine Coolant Temperature (ECT) sensor -G62-
6 - Secondary Air Injection (AIR) solenoid valve -N112-

Secondary Air Injection system:
7 - Intake Air Temperature (IAT) sensor -G42-
8 - Intake manifold change-over valve -N156-
9 - Throttle Valve Control Module -J338-
10 - 4-pin harness connector

Black
for Heated Oxygen Sensor (HO2S) 2 -G108-, bank 2 before catalytic converter and oxygen sensor heater -Z28-, cylinder bank 2
11 - 3-way connector

Brown
For Knock Sensor (KS) 2 -G66-, cylinder bank 2
12 - 3-way connector

Gray
For Engine Speed (RPM) sensor -G28-
13 - Engine Control Module (ECM)
(control module for Motronic -J220-)

Installation location: in protective housing, radiator tank on left
14 - Fuel pressure regulator
15 - Camshaft Position (CMP) sensor 2 -G163-

Engine bank 2
16 - Heated Oxygen Sensor (HO2S) 2 -G108-, bank 2 before catalytic converter, 50 Nm
17 - Engine Speed (RPM) sensor -G28-
18 - Knock Sensor (KS) 2 -G66-

Engine bank 2
19 - Valve -2- for camshaft adjustment -N208-

Engine bank 2
20 - Ignition coils (-N-, -N128-, -N15

With power output stage -N122-
21 - Knock Sensor (KS) 1 -G61-

Engine bank 1
22 - Fuel injector (-N30-, -N33-, -N83-, -N84-)
23 - Camshaft Position (CMP) sensor -G40-

Engine bank 1
24 - Ground connection

On engine bracket, right side
25 - Heated Oxygen Sensor (HO2S) -G39-, bank 1 before catalytic converter, 50 Nm
26 - Valve -1- for camshaft adjustment -N205-

Engine bank 1
27 - Secondary Air Injection pump motor (V101)

Secondary Air Injection system:
28 - Mass Air Flow (MAF) sensor -G70-
29 - Evaporative Emission (EVAP) canister purge regulator valve -N80-

On air cleaner housing
EVAP system:







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[billr]

Jim,

Well it should, but remember I'm the guy that took 40 yrs. to figure out a grease-gun! I looked at the list and think I am looking for the G79 TP sensor and the G185 accel pedal sensor. But I don't see them on the diagram, I think they are probably inside under the dash. That item #1 is the green 4-pin connector for the (bank 1) O2 sensor. Any pix of the pedal area? How about a schematic of the throttle circus?

 

[Jim Fairbanks]

OK...let me know if this helps and if you need more...Jim......Throttle Position (TP) sensor, checking

Recommended special tools and equipment



V.A.G 1526 multimeter or V.A.G 1715 multimeter
V.A.G 1594 Connector test set
Wiring diagram
Test requirement



The respective fuses of Motronic Engine Control Module (ECM) - J220- must be OK:
Function
Both the Throttle Position (TP) Sensor -G79- and the Sender -2- for accelerator pedal position -G185- are located at the accelerator pedal and communicate the driver's intentions to the ECM completely independently of each other. Both sensors are stored in one housing.

Test sequence

Note: When servicing terminals in the harness connector for the Intake Air Temperature (IAT) sensor, use only gold-plated terminals.



Remove footwell cover (driver's side).
Disconnect 6-pin connector from Throttle Position (TP) Sensor.
Switch ignition on.
Checking voltage supply and wiring to control module


Connect multimeter to the following connector terminals for voltage measurement Terminal 1 + Ground (GND)
Terminal 1 + 5
Terminal 2 + Ground (GND)
Terminal 2 + 3

Specified value: at least 4.5 V



Switch ignition off.
If specified values are not obtained:


Connect test box to control module wiring harness, connect test box for wiring test. See: Computers and Control Systems\Testing and Inspection\Reading and Clearing Diagnostic Trouble Codes\Scan Tool Connecting\With Generic Scan Tool\Test Box, Connecting For Wiring Test
Check wires between test box and 6-pin connector for open circuit according to wiring diagram. Terminal 1 + socket 72
Terminal 2 + socket 73
Terminal 3 + socket 36
Terminal 4 + socket 35
Terminal 5 + socket 33
Terminal 6 + socket 34
Wire resistance: max: 1.5 Ohms



Also check wires for short circuits to each other, to vehicle Ground (GND) and to B+.
Specified value: Infinite Ohms

If no malfunction is detected in the wiring and if the voltage supply was OK:


Replace accelerator pedal position sensor.
Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
Generate readiness code. See: Computers and Control Systems\Testing and Inspection\Monitors, Trips, Drive Cycles and Readiness Codes


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