2002 Jetta FAILED smog test! Nooooo!

[jenxo]

So I took my 2002 Jetta Tdi with 245,000 miles to get smogged last week, after
already being miffed at having to put up with emissions nonsense in California.

The check engine light is on, so the smog tech said it would fail.
He said I failed.

The OBD II Diagnostics Trouble codes:

Emissions-related powertrain DTCs, mode3:
Electronic control unit ID: OA
P0674
Manufacturer specific code
P1556
Manufacturer specific code
P0740
Torque converter clutch circuit malfunction
Continuously monitored systems DTCs, Mode 7

Any ideas what I'm looking at? What is needed to fix. I looked up some codes and only found 1 of them...related to glow plug. So that's a clue!


Background info.
Well maintained machine.
The belt/pulley + oil service was done 6 months ago ($700). I think 2 glow plugs were replaced. 2 appeared to be good still.
The Fuel injection pump was resealed for $450 at Wild Rose motors in Whittier, CA
My upper cooling/intercooler pipe has a small hole. I will replace the pipe.

 

[Got Bearings?]

Why would anyone take a car to a smog test when the check engine light is on? Do you like to give away money? If so, I'll send you my paypal account. A check engine light is an automatic fail. When the tech said it would fail, why did you have it smogged anyway?

Then you say it's a "well maintained machine." If you have multiple DTC's, it's not "well maintained".

For the first code - P0674. Cylinder 4 glow plug is the possible culprit. Swap it with #3 and see if the DTC follows it (P0673). If it does, replace glow plug. If it doesn't, it's probably the harness. With that mileage, it may not be a bad idea to change all the glow plugs and harness. IDParts.com usually have a package deal. Search for Glowplugs 2.0 on here for more info.

For the P1556 code, it's probably related to the intercooler pipe hole. See here for more info. http://forums.tdiclub.com/showthread.php?t=336027

For the P0740 code, it's looks like it's your transmission. With that mileage, it could be on it's way out. See these threads
http://forums.tdiclub.com/showthread.php?t=347336
http://forums.tdiclub.com/showthread.php?t=252885

 

[oilhammer]

Yep, well maintained vehicles don't have warning lamps on.

Unfortunately in your case, one of those DTCs points to a possible major transmission problem. Could be something as simple as a TC solenoid.

 

[jenxo]

Hi GOTBEARINGS,
You are of course absolutely correct.
However, the SMOG center is owned by a friend, NO CHARGE.
He had the equipment.
Plus I'm new to TDi, and actually erroneously ASSUMED the smog test was just a visual!
Thank for your help and kindness in helping me learn.

 

[Rual817]

Actron CP9575
This is an inexpensive code reader $80-$130. I have one and it works great. AutoZone (130) carries or you can get a little cheaper on Ebay. I'd love to have a VagCom but this will do for now.

 

[romad]

At $130 you're more than 50% to VAG-COM; unless like me you don't use Windows. Then it is only about 10%!

 

[oilhammer]

I love it when people think a generic OBD2 scan tool is worth a darn...

Funny how none of those people have ever used a real scan tool.

 

[Dave_D]

If all you want to do is read codes then you can download the shareware version and get one of the cheap cables on eBay that is known to work with it. There is a thread on here somewhere noting some that are know to work. This will get you the VAG specific codes and give you access to the other modules as well that a generic OBD reader cannot access.

If you then decide that you need some of the registered version functions you can do so and have the ability to tweak things, check timing, etc.

Dave

 

[turbocharged798]

Snag yourself a cheap KKL "dumb" interface of ebay and run VCDS lite. It will read some codes and give you the taste what full VCDS is like. Totally legal as well, unlike some stuff.

 

[firehawk618]

I love it when people think a generic OBD2 scan tool is worth a darn...

Funny how none of those people have ever used a real scan tool.

This is true.

 

[jenxo]

Hi "GOTBEARINGS?",
Latest update Sept 2012 :
I took my 2002 Tdi Jetta to my regular mechanic :
1) He Replaced the intercooler pipe (he had originally caused the damage by not tightening the clamp, and the pulley rubbed up against it)
2) he checked the glow plugs, all were good. Cable seemed loose, he tightened it, and now :

P0740 code is till showing and P1556 is still showing.
BUT the CHECK ENGINE light is NO LONGER ON!

Looks like P0740 is really the most critical one to check. "Torque Converter clutch circuit malfunction"

What is STRANGE is : My Transmission (automatic) is working PERFECTLY.

I'm going to carefully study the links you kindly provided me.

Again, your generosity in sharing and advising has helped me more than I can ever repay.

Thanks.

 

[jenxo]

Hi "OILHAMMER",
New to Tdi, my first one this last February.
How to know if indeed it is the TC Solenoid?
Help appreciated.

 

[Got Bearings?]

1. Did you/mechanic clear the codes after you took it back to him and fixed the issues?
If "no", clear the codes and then drive around for a few days and recheck for codes.
If "yes", keep looking for issues re: P1556

from http://wiki.ross-tech.com/wiki/index.php/Category:Fault_Codes
17964/P1556 - Charge Pressure Control: Negative Deviation
Possible Symptoms
Reduced power output
Limp mode

Possible Causes
Boost Pressure too Low
Hoses/Pipes incorrect connected, disconnected or leaking
Charger Pressure Control defective
VNT (variable nozzle turbo): nozzles stuck
Solenoid Valve for Boost Pressure Control (N75) defective

Possible Solutions
Check Hoses/Pipes to/between Components
Check Solenoid Valve for Boost Pressure Control (N75)
Check / Clean / Replace Charge Pressure Control
Check / Clean mechanism for variable nozzles

As for your tranny, I'm not familiar at all with them but I've read enough about them and how awful they are. With 245k miles, you may need to replace it.

BTW, if you still have stored codes (codes without the check engine light on), you will fail again.

 

[JWest]

Pass Smog with a P0740 Code

Hi "GOTBEARINGS?",
Latest update Sept 2012 :
I took my 2002 Tdi Jetta to my regular mechanic :
1) He Replaced the intercooler pipe (he had originally caused the damage by not tightening the clamp, and the pulley rubbed up against it)
2) he checked the glow plugs, all were good. Cable seemed loose, he tightened it, and now :

P0740 code is till showing and P1556 is still showing.
BUT the CHECK ENGINE light is NO LONGER ON!

Looks like P0740 is really the most critical one to check. "Torque Converter clutch circuit malfunction"

What is STRANGE is : My Transmission (automatic) is working PERFECTLY.

I'm going to carefully study the links you kindly provided me.

Again, your generosity in sharing and advising has helped me more than I can ever repay.

Thanks.

I am new to the forum so I apologize if this is in the wrong thread. I live in CA and have had the P0740 Code going on five years. I understand that my TC isn't locking up and that it is in the valve body. I tried several quick fixes but wasn't willing to put a lot of money into the Valve Body. To pass smog, I clear the code with my scanner, then drive around for 150 miles in the "3" position on the gear shift, not "D." After I get enough miles and my scanner tells me that all sensors are up, I take it in to smog. Obviously, this is for those who don't want to put repair money in to the vehicle. My car has 196K and still shift smooth, but I can feel the TC slip when I am light on the pedal in 4th gear. Hope this helps someone. Took me a while to figure out the TC doesn't lockup until 4th gear.

 

[scooperhsd]

No - the TC locks in EVERY gear if it it is working correctly - so you kind of get an 8 speed transmission effect - 1u, 1L, 2U,2L, 3U,3L, 4U,4L. when it is working correct the changes between U and L happen so fast in the lower gears that you can't tell. My Beetle ran for 120K miles with that code happening regularly until the final demise of the transmission at 252,000 miles (where upon I replaced it with a 5 speed manual). @ 245,000 miles - I'd check with someone who is a real expert in these transmissions (coolairvw in KC as an example) who might be able to get it repaired, or start saving up for a 5 speed manual conversion (mine ran $3000).

 

[bizzle]

No - the TC locks in EVERY gear if it it is working correctly

I read JWest's post to mean that his is not working correctly and that it took him a while to figure out that his TC wasn't locking until 4th gear as the issue.

 

[JWest]

No - the TC locks in EVERY gear if it it is working correctly - so you kind of get an 8 speed transmission effect - 1u, 1L, 2U,2L, 3U,3L, 4U,4L. when it is working correct the changes between U and L happen so fast in the lower gears that you can't tell. My Beetle ran for 120K miles with that code happening regularly until the final demise of the transmission at 252,000 miles (where upon I replaced it with a 5 speed manual). @ 245,000 miles - I'd check with someone who is a real expert in these transmissions (coolairvw in KC as an example) who might be able to get it repaired, or start saving up for a 5 speed manual conversion (mine ran $3000).

Thanks for the clarification. But, I will say that leaving it in "3" worked for me and I know there are alot of CA TDI people that should at least give it a try. I never got a single 0740, or pending 0740 driving it like this before the test.

 

[nwdiver]

What is needed to fix.

Just a suggestion

Consumer reports


Those smog checks exist for a reason... and they work.

 

[flee]

Those smog checks exist for a reason... and they work.

And this with at least double the vehicles and miles driven!

 

[jenxo]

it was the TRANSMISSION.
Reconditioned it for $2,000. Engine light gone. SMog passed.

 

[gmcjetpilot]

1/4 million miles. you got your monies worth of that trans.

 

[Thunderstruck]

Money well spent. Congratulations on gittin' her fixed.