VW Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
38 Posts
Discussion Starter #1
Just picked up a (new to me) Jetta as a commuter car for my wife. In checking it over, I have found a few things needing attention. I'll list them with my limited understanding. Any expounding by other members would be greatly appreciated.

First, the brake pad wear indicator light was on when I bought it, and thought it would be an easy fix so I wasn't worried about it. It was, once I learned how it worked. Turns out, the doofus I bought the car from replaced the front pads, but not with the type with a sensor. So, I crimped the two wires together and the light went out.

Second, shortly after getting the car (about 10-15 miles) the CEL came on. So, I took it to the local parts store (O'Reilly's) and had them pull the code and reset it. The guy at the store told me it had to do with the catalytic converter and that it was below efficiency threshold (whatever that means). I have driven it 30 miles or so and it hasn't come back on again. I did however put some Techron type fuel additive in it and filled up the tank. This XP additive has helped my other cars in the past and it may or may not help here.

Third, there were other small issues, but nothing to do with drivability, so I'll leave them out of this post.

Now, I seek your suggestions and recommendations. It has 95,000 miles on it and it doesn't look like the O2 Sensors have been replaced. The spark plugs look good (chocolate brown) but appear somewhat worn and may have been in there a while. I'm also pretty sure the timing belt hasn't been replaced, nor have the plug wires. So, before I pull the trigger on the purchase of such items, is now a good time to do these likely neglected items? I welcome your thoughts.

Oh, and while I think of it, I'm looking for 2 wheel covers (10 spoke OEM) for the same auto.

Thanks in advance for your interest and assistance.

Michael B.
 

·
Registered
Joined
·
353 Posts
sounds like the brakes are fine, i would personally just ignore the cat issue, nothing to really worry about.
the o2 sensors are probably fine, but you might want a second opinion on that.

i would, however, change out the plugs, it's a cheap fix and you can only benefit from it. NGK gapped to .032. ECS has them for like 2 bucks each.
also, DEFINITELY check the timing belt. (or chain if its a vr6) i just had mine fail at 50k and trust me, it SUCKS. it's worth the money to have it checked out now. trust me, it'll cost alot more if it fails.

and for the wheel covers, ecstuning.com should have everything you need. they've always served me well.

good luck and enjoy the new dub!
 

·
Registered
Joined
·
1,869 Posts
That code will come back in <80 miles for sure.

Heres your to do in the next 20k-40k miles (off top of my head)

everything below is simple and cheap for even an amatuer except the timing belt.
The guys on this forum can walk you through any of it.

timing belt/water pump
complete rad flush
oil/filter
fuel filter
air filter
clean MAF in alcohol bath and intake (butterfly valve)
new vacuum hoses for aged ones
check injectors for function
new plugs and wires (essential, they start to fail at around 100 to 135k)
tighten rear light housings (10mm bolts) -critical - im serious
replace coolant sensor maybe fan switch
check replace valve cover/oil cooler/oil filter/pan gasket (depending on condition)
clean any suspect electircal fittings and connections
clear out sunroof drains with compressed air
change cabin filter
check alterntor diodes/functionality
replace serpentine belt
check fuel tank cap for pressure
check water tank cap for pressure
check PCV
grease the nipples and linkage
replace O2 sensors
retension older push fit electrical connections
replace any fuses and relays
inspect door boots and dash connections
grease locks
grease bake cable
swap tranny fluid.
 

·
Registered
Joined
·
38 Posts
Discussion Starter #4
That code will come back in <80 miles for sure.
Well, just went out to dinner and on the way, the CEL came back on. 35 miles, exactly. Do you suppose changing the O2 Sensors, plugs and wires will keep the CEL from coming back on? Or, am I up against a cat replacement, period? I guess I should have written down the code, but if memory serves me correctly, I think it was "P0420" (Catalyst System Efficiency Below Threshold).

Thanks for the list of things to do... I will be getting them done during the winter months as it's too hot to do anything in the summer here in Phoenix.

I have changed my share of timing belts, filters and pumps, etc. Last winter I replaced the head gasket on my Mercedes 300CE (dual overhead cam). So, none of actual work will be foreign to me, just the car and its idiosyncrasies.

Again, thanks. Looking forward to helping someone else once I get my sense of direction.

Michael B.
 

·
Registered
Joined
·
38 Posts
Discussion Starter #5
More Cat Research

After more research, I found this at OBD-II Trouble Codes - DTC Codes Car Repair

P0420 OBD-II Trouble Code
Catalyst System Efficiency Below Threshold (Bank 1)

What does that mean?
The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

Symptoms
You will likely not notice any drivability problems, although there may be symptoms.

Causes
A code P0420 may mean that one or more of the following has happened:
  • Leaded fuel was used where unleaded was called for
  • An oxygen sensor is not reading (functioning) properly
  • The engine coolant temperature sensor is not working properly
  • Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
  • Retarded spark timing
  • The oxygen sensors in front and behind the converter are reporting too similar of readings
Possible Solutions
Some suggested steps for troubleshooting a P0420 error code include:
  • Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required.
  • Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
  • Inspect the downstream heated oxygen sensor (HO2), replace if necessary
  • Replace the catalytic converter
With this information, I think I'll first replace the O2 Sensors, since it looks like they haven't been replaced anyway. If the code comes back, then I'll look into replacing the Cat. Seems the right way to go at this time. Any thoughts from others with more O2 sensor experience?

Happy Monday!
 

·
Registered
Joined
·
38 Posts
Discussion Starter #6
Update: Well, I replaced the O2 Sensors (forward and aft) and the P0420 code returned after a short time. I was pretty sure the sensors hadn't been replaced since new and with 95k on it, I thought it was time anyway. With some hope, I was thinking this would correct it, but no joy.

So, now I'm in the hunt for a new Cat. I see this company (http://www.macautoparts.net) has a few. The price looks good. I'm assuming they're a reputable company.
 

·
Registered
Joined
·
1,869 Posts
Unfortunately the CAT aint cheap. I dont know that company.

ALthough my usual source is more expensive than your link

GermanAutoParts.com

I would get it from a junkyard for pennies on the dollar if I were you.
 

·
Registered
Joined
·
962 Posts
Goto your local VW dealer. Your car qualifies for a warranty recall on the Cat. 10 years, 100,000miles. 2.0 motor only.
 

·
Registered
Joined
·
38 Posts
Discussion Starter #10
@Geezir - Thanks!

Went to the dealer on 12/29 and the service writer told me, "no, it's not covered, but here's a number you can call." So, I called VW and gave them my VIN and engine code and the nice gal on the other end said, "According to your VIN and if in fact you have engine code AVH, the converter is covered for 10 years and 100k miles."

Then she said, "I'll have the dealer call you by end of business tomorrow."

I was a bit apprehensive, but VW has made a believer out of me, because I walked out of the dealer on Monday (01/03) with a new Catalyst (installed) for $0.!!!
 

·
Registered
Joined
·
1,869 Posts
@Geezir - Thanks!

Went to the dealer on 12/29 and the service writer told me, "no, it's not covered, but here's a number you can call." So, I called VW and gave them my VIN and engine code and the nice gal on the other end said, "According to your VIN and if in fact you have engine code AVH, the converter is covered for 10 years and 100k miles."

Then she said, "I'll have the dealer call you by end of business tomorrow."

I was a bit apprehensive, but VW has made a believer out of me, because I walked out of the dealer on Monday (01/03) with a new Catalyst (installed) for $0.!!!
That is amazing! GEEZIR for the win!!!
 

·
Registered
Joined
·
1,869 Posts
When someone posts an earth shaking repair revelation it shall now be referred to as "goin all Geezir" or "getting Geezy"
 

·
Registered
Joined
·
335 Posts
I used to have that same code pop up constantly when i put my exhaust on, so after the turbo replacement i got a stage 2 apr chip and asked if they could put a test pipe code in there, hasnt popped up since...
 
1 - 20 of 21 Posts
Top