Need help with 1998 Jetta CEL light

lbarrack · November 12th, 2007, 11:08

First - I have been through this forum and found it very helpful.
Some history - I bought this car a few weeks ago for 3500.00. It had 193000 miles on it but seemed in good shape - small dealer, saw it would need tires and stereo but little else.

After driving it a few days, noticed the airbag light would flash on and off (seems to be related to bumps in the road). Had a stereo and amp put in. A few days later the CEL light came on. I got my mechanic (who does not specialize in VW's) to read the code. It was realated to vacuum hose (P0605). I checked your forum and found the procedure to replace the hose in the ECM and had my mechanic tear it appart. He checked the vacuum hose with on it and it was measuring no vacuum loss on his tool. He then suggested to take it to the dealer.

The dealer found other hoses that were bad, replaced them and cleared the codes. About 40 min later the CEL light came on again. I took it back to the dealer and this time they said it's throwing out a 65535 code and I would need to replace the ECM. But they also said that it appeared as if I was running normally, there were no vacuum lline problems and that I could just ignore it.

Now, however, my airbag light is coming on more frequently. Are they related? I saw something here about the airbag relay getting corrupted but it looks like it applies to later models.

Any help would be appreciated. By the way, the car drives fine, no loss of power or gas mileage (about 38 all around).

rdkern · November 12th, 2007, 11:16

Quote:

Originally Posted by lbarrack

First - I have been through this forum and found it very helpful.
Some history - I bought this car a few weeks ago for 3500.00. It had 193000 miles on it but seemed in good shape - small dealer, saw it would need tires and stereo but little else.

After driving it a few days, noticed the airbag light would flash on and off (seems to be related to bumps in the road). Had a stereo and amp put in. A few days later the CEL light came on. I got my mechanic (who does not specialize in VW's) to read the code. It was realated to vacuum hose (P0605). I checked your forum and found the procedure to replace the hose in the ECM and had my mechanic tear it appart. He checked the vacuum hose with on it and it was measuring no vacuum loss on his tool. He then suggested to take it to the dealer.

Well, this hose measures pressure - not vacuum. If he was in there, he should have swapped out that hose - they deteriorate and the time spent to get there is about 100X the cost of replacing it once there. His test told you nothing.

Quote:

Originally Posted by lbarrack

The dealer found other hoses that were bad, replaced them and cleared the codes. About 40 min later the CEL light came on again. I took it back to the dealer and this time they said it's throwing out a 65535 code and I would need to replace the ECM. But they also said that it appeared as if I was running normally, there were no vacuum lline problems and that I could just ignore it.

That little hose in the ecu causes this type of problem. Swap it out.

Quote:

Originally Posted by lbarrack

Now, however, my airbag light is coming on more frequently. Are they related? I saw something here about the airbag relay getting corrupted but it looks like it applies to later models.

Any help would be appreciated. By the way, the car drives fine, no loss of power or gas mileage (about 38 all around).

Airbag lights mean one of two things - the airbag is getting bad, or the connections are bad.

Only 38 mpg? Odd - do you drive almost exclusively city?

Antsrcool · November 12th, 2007, 11:17

http://www.ross-tech.com/vag-com/vw_issues.html#Airbags the 65535 code that you have is for your airbag. That link will help u fix that. We will need a code form teh ECM to see what that CEL is all about

lbarrack · November 12th, 2007, 20:30

Thanks for the fast replies. I'll try to answer your questions to the best of my knowledge.

On the line inside the ecm, he hooked up a gadget to one end and it pumped pressure into it and did not loose any pressure. That is why he did not replace it.

They cleared out all the codes when they reset the ecm. When the cel light came on again it only threw out the 65535 error this time. They said it was a checksum error but could not find anything wrong. Do you think that this is now an airbag related problem? The light was not coming on for that when they had it.

As for the gas mileage - it is disapointing but I do hit a lot of stop and go traffic when I drive. I have had the car for only 3 or 4 weeks and perhaps as my handling of a stick improves, so will my driving.

rdkern · November 13th, 2007, 08:57

Last I have to say on this subject.

push here

Replace the hose, and the one that goes to the innercooler from the ecu.

jettagirl98 · November 22nd, 2007, 18:45

Well, I am definitely not the expert here but sounds to me like you may have two completely unrelated problems here - vacuum hose and airbag issues. I also just recently bought a Jetta TDI, and have the P0605 code. Like a true newbie, I bought a new ECM off of Ebay - didn't help. So, then looked at this forum and looked at the vacuum hose inside the ECM - this hose was badly deteriorated on both the original and the one I bought! Unfortunately, this still hasn't fixed the problem...Next I'm going to try to replace some of the other vacuum hoses. I think your bad mileage could be due to this error though - if the car is in limp mode, my understanding is your mileage can go way down. My car also is only getting ~30 mpg. Good luck with yours, let me know when you fix it!

jettagirl98 · January 27th, 2008, 20:41

Just wanted to update everyone, since I finally fixed my P0605 CEL. The problem was (1) bad hoses in original ECM and Ebay ECM; and (2) bad original ECM. Now that the Ebay ECM is put in with a new hose, it seems to have fixed the problem. I've driven it 5 or 6 times with no CEL so far.

One question - I just had my timing belt replaced, and now I've put the new ECM in the car. Will this screw up the timing?

rdkern · January 30th, 2008, 13:42

Contragulations. Glad it's fixed.

Hope it's fixed for the long haul.

No, new ecm should not impact timing.

jettagirl98 · February 10th, 2008, 09:28

Nope, not fixed for the long haul. Sigh. All the vacuum hoses but one are done, and I'm not sure I have the confidence to try that one myself. Am trying a new N75 valve. Incidentally the CEL now displays two error codes: P0605 and P1550 "charge pressure deviation". I am hoping both these error codes are related to the same problem.

jettagirl98 · March 9th, 2008, 22:53

OK, so I've replaced all the vacuum hoses (unless there are some hiding where you can't see them?). I've also replaced the N75 valve. No luck. From other posts on this forum I'm guessing it's time to look at my wastegate acutator. How tough of a job is this? Keep in mind I am a complete novice (I will not admit publicly how long a couple of those vacuum hoses took me) but I am also extremely tenacious. So...I'd rather not spend the money on a mechanic...how bad can I screw it up??
Thanks!

paramedick · March 10th, 2008, 07:00

Not hard to do. Only thing is to have a bicycle pump and an adapter that will connect to the pump and the vacuum tubing. Many hardware stores sell an adapter that will work with the pump.

Disconnect the line to the wastegate actuator. Connect the bicycle pump to a short piece of vacuum tubing. Connect that to the actuator.

Have someone pump away while you look at/touch the rod on the actuator. It should start moving at <10psi pressure. If it moves, lubricate the linkage the rod connects to with a good spray synthetic lubricant. I like teflon lubes.

If it doesn't move, check the pressure gauge on the pump. Does the actuator hold pressure? Good. Your problem may be a rusted linkage at the rod/turbo interface. Spray the linkage with some PBBlaster rust penetrant and let sit a bit. Try again with the pump. If it moves, work it with the pump to free it up. If it doesn't move, you may have to get something to manually move the linkage until it breaks free. Then exercise it until it moves smoothly and lube as above.

If it doesn't hold pressure or leaks off slowly, you have a bad actuator and it will need to be replaced.

coot · March 16th, 2008, 10:50

Hey all..

I'm a newbie too, with thee same dreaded PO605 code coming up... I went so far as to Jason's TDI repair in Wisconsin here, who replace all my high prsure lines... he really has this car (97' Jetta) running so much better, but..... On the way home, yep.. the CEL came back on coding PO605 at the local AutoZone.. replace ECM...???

Guess I don't understand how this car runs so well... if there is a ECM issue...?? Guess I could get used to the little orange engine pic, but...

And on that last post... Are the comments on the wastgate acctuator still realtive to the PO605...?

I'll stay tuned... light still on.!

rdkern · March 16th, 2008, 10:55

I believe the P0605 often means you need a very expensive $.10 piece of tubing to replace -

coot · March 16th, 2008, 19:26

Thanks rdkern

I did replace the hose, but still have the CEL. Is it that that code needs to be cleared with VAG-COM... Should it have cleared itself (I've read that after "X" starts... the system clears itself...??)

Car runs fine if I have to live with it...!!

rdkern · March 16th, 2008, 19:29

I don't know if this is one that will clear the cel after 10-20 starts - it does need to be removed from the ecu to have the dtc cleared. Clear it to see if it's fixed. The system doesn't "clear" itself, but often the cel will go out after a certain number of starts if the condition doesn't repeat itself.