Jetta Check Engine Light Keeps coming back on

[garth_schultz]

Folks - My 1996 Jetta GL (manual transmission, 96K) engine light came on a couple of days ago. I took in to the shop to get a much needed tune-up, and have them check out the light. They did a full tune up - plugs, wires, etc...and replaced the vaccum seal for the oil-dipstick, which was broken.The guys at the shop did say that the clutch needs replacing, but they don't seem to think that it is causing the engine light to come on, and they can't find what is causing it.

Got the car back, and in some ways it feels better (smoother, I think), but the engine light came back on within a day, and it has stalled on me a couple of times at low RPM's (which it never did before). I brought it back to the shop, they put the computer machine on it, tightened down the gas cap (which I hadn't touched since they worked on it) and sent me on my way. The engine light came on again 40 miles later, and the gas cap was not the issue, cause I checked it.

Symptoms:
-Fluctuates at Idle, even stalls (now, not before I brought it in this week).
-Sputters a bit while accellerating/deccellerating at low RPM's 12 - 20
-Gas mileage has dropped from 30 a year ago, 28-29 recently, and 26 now.
-When accelerating quickly, clutch seems to slip - RPM's jump with no jump in speed.
-About 1/4 of the time, when I turn the key to start it nothing happens, or it turns and doesn't catch, like there isn't enough fuel. The rest of the time it starts just fine.

What is causing these things? Why does the engine light keep coming on? And, if the guys at the shop can't figure it out, what do I do? Is it possible that the engine light just comes on, or is there always a good reason?

The help is much appreciated.

[IowaHawkeye24]

As far as all the stalling goes and RPM's shooting up you did need a new clutch. That is what mine did right before mine needed replaced. And for as far as the check enginge light goes what the heck kind of shop are you taking it to that can't tell you whats wrong? You should be able to just hook it up to and OBD code reader and it should tell you whats wrong. I can do that with my own and know exaclty what it is. It usually costs about 125 for the cheap ones so I would suggest just getting one instead of paying about 125 to have them just hook it up.

[stuzman]

Originally Posted by garth_schultz

Folks - My 1996 Jetta GL (manual transmission, 96K) engine light came on a couple of days ago. I took in to the shop to get a much needed tune-up, and have them check out the light. They did a full tune up - plugs, wires, etc...and replaced the vaccum seal for the oil-dipstick, which was broken.The guys at the shop did say that the clutch needs replacing, but they don't seem to think that it is causing the engine light to come on, and they can't find what is causing it.

Got the car back, and in some ways it feels better (smoother, I think), but the engine light came back on within a day, and it has stalled on me a couple of times at low RPM's (which it never did before). I brought it back to the shop, they put the computer machine on it, tightened down the gas cap (which I hadn't touched since they worked on it) and sent me on my way. The engine light came on again 40 miles later, and the gas cap was not the issue, cause I checked it.

Symptoms:
-Fluctuates at Idle, even stalls (now, not before I brought it in this week).
-Sputters a bit while accellerating/deccellerating at low RPM's 12 - 20
-Gas mileage has dropped from 30 a year ago, 28-29 recently, and 26 now.
-When accelerating quickly, clutch seems to slip - RPM's jump with no jump in speed.
-About 1/4 of the time, when I turn the key to start it nothing happens, or it turns and doesn't catch, like there isn't enough fuel. The rest of the time it starts just fine.

What is causing these things? Why does the engine light keep coming on? And, if the guys at the shop can't figure it out, what do I do? Is it possible that the engine light just comes on, or is there always a good reason?

The help is much appreciated.

Since they tightened the gas cap, I would assume that you have an EVAP problem. It's possible that the cap could be bad (not sealing correctly) or there is a leak in another part of the system such as canister, purge solenoid, associated vacuum line(s), etc.

Since the vehicle is running pretty rough with stalling, I would suspect that there would be another code set for this. An engine scanner would be needed to look at some of the data. Also, since you say the car didn't do this before the tune-up, it's possible that the tech may have forgotten to plug something back or inadvertently unplugged something. Take a look around the engine and see if you see anything loose such as a vacuum line, spark plug wire loose, etc. Other possibilities which can cause these symptons are a dirty throttle body, idle control assembly or the EGR system.

The clutch sounds worn and will need replacement.

As far as the ignition switch, it sounds like a bad switch assembly.

Keep us posted of your results and good luck with it!

[janea]

Just a little info regarding your check engine light.I noticed someone replyed by asking what kind of mechanic did you take it to and why could they NOT find the problem with your CK Eng LT.Well...listen to this:My 95JettaGL broke down on the highway after stalling a few times it finally just quit.Took it to the dealer (VW in Connecticut)and they did$3000 worth of work on it(replaced the mass airflow meter,and,well I do not have all the info w/me) but 10 minutes after driving off the lot the check engine light came on.I took it back and they replaced the temperature gauge sensor.It came on again.I took it back and they hooked it up to do another diagnosis.....no body could tell why the Ck Eng Lt kept coming on and this is a DEALER!I gave up and this was 2 years ago and the damn thing STILL comes on but the car always ran damn well.To this day I still have a check engine Lt that goes on.It DID stop for 5 months straight when I found a gas station with particularly good,clean gas but when I moved and switched stations the light came back on.I would,however,like to see it go off once and for all.You would think $3000 would have done it!Good luck~~~~~J

Originally Posted by garth_schultz

Folks - My 1996 Jetta GL (manual transmission, 96K) engine light came on a couple of days ago. I took in to the shop to get a much needed tune-up, and have them check out the light. They did a full tune up - plugs, wires, etc...and replaced the vaccum seal for the oil-dipstick, which was broken.The guys at the shop did say that the clutch needs replacing, but they don't seem to think that it is causing the engine light to come on, and they can't find what is causing it.

Got the car back, and in some ways it feels better (smoother, I think), but the engine light came back on within a day, and it has stalled on me a couple of times at low RPM's (which it never did before). I brought it back to the shop, they put the computer machine on it, tightened down the gas cap (which I hadn't touched since they worked on it) and sent me on my way. The engine light came on again 40 miles later, and the gas cap was not the issue, cause I checked it.

Symptoms:
-Fluctuates at Idle, even stalls (now, not before I brought it in this week).
-Sputters a bit while accellerating/deccellerating at low RPM's 12 - 20
-Gas mileage has dropped from 30 a year ago, 28-29 recently, and 26 now.
-When accelerating quickly, clutch seems to slip - RPM's jump with no jump in speed.
-About 1/4 of the time, when I turn the key to start it nothing happens, or it turns and doesn't catch, like there isn't enough fuel. The rest of the time it starts just fine.

What is causing these things? Why does the engine light keep coming on? And, if the guys at the shop can't figure it out, what do I do? Is it possible that the engine light just comes on, or is there always a good reason?

The help is much appreciated.

[stuzman]

Originally Posted by janea

Just a little info regarding your check engine light.I noticed someone replyed by asking what kind of mechanic did you take it to and why could they NOT find the problem with your CK Eng LT.Well...listen to this:My 95JettaGL broke down on the highway after stalling a few times it finally just quit.Took it to the dealer (VW in Connecticut)and they did$3000 worth of work on it(replaced the mass airflow meter,and,well I do not have all the info w/me) but 10 minutes after driving off the lot the check engine light came on.I took it back and they replaced the temperature gauge sensor.It came on again.I took it back and they hooked it up to do another diagnosis.....no body could tell why the Ck Eng Lt kept coming on and this is a DEALER!I gave up and this was 2 years ago and the damn thing STILL comes on but the car always ran damn well.To this day I still have a check engine Lt that goes on.It DID stop for 5 months straight when I found a gas station with particularly good,clean gas but when I moved and switched stations the light came back on.I would,however,like to see it go off once and for all.You would think $3000 would have done it!Good luck~~~~~J

I'm not surprised with your story janea as it's typical of a lot with dealers these days. My dad was an auto mechanic for 45 years and I can remember in his days when most of the techs had years of experience. Today, and this is not to give any short comings to the younger guys, but a lot of the techs are a lot younger. I've met and talked with some of them and some are pretty sharp, but most lack the experience that's also needed to help diagnose autos. Anyway, for people who like to save money and do their own work, a person needs to learn all they can to be successful in their own car repairs. By the way, do you remember what the code was and if not, why don't you go ahead and read the code for yourself. I understand that you don't even need a scanner or code reader for a 95 and try to do some diagnosis for yourself.

[Passat1.8]

Have either of you checked your o2 sensors Volkswagon sensors are very fussy and the littlest thing can set them off and an o2 sensor can affect your idle.

[janea]

Originally Posted by stuzman

I'm not surprised with your story janea as it's typical of a lot with dealers these days. My dad was an auto mechanic for 45 years and I can remember in his days when most of the techs had years of experience. Today, and this is not to give any short comings to the younger guys, but a lot of the techs are a lot younger. I've met and talked with some of them and some are pretty sharp, but most lack the experience that's also needed to help diagnose autos. Anyway, for people who like to save money and do their own work, a person needs to learn all they can to be successful in their own car repairs. By the way, do you remember what the code was and if not, why don't you go ahead and read the code for yourself. I understand that you don't even need a scanner or code reader for a 95 and try to do some diagnosis for yourself.

Can you give me some step by steps on how I go about reading a code or getting it to read?I would really appreciate it!Thanks!

[stuzman]

Originally Posted by janea

Can you give me some step by steps on how I go about reading a code or getting it to read?I would really appreciate it!Thanks!

Below is a step by step procedure for reading the code(s) on early and latter 94 and all 95 Jettas and for erasing the codes. Most of this comes from the factory manual with the exception of my own thoughts to clarify a step. In this procedure, you can use a jumper wire or you can use a DTC adapter which can jump the two pins listed below. According to the service manual, it's attached to the wiring harness with a wire tie under the rear seat if your vehicle doesn't have ABS. If it has ABS, then it's stored beneath the ABS coaxial cable next to to the ABS control unit. If you don't have this adapter, just use a jumper wire.

If your vehicle is an earlier 94, then its possible that you have two connectors; one connector is black and one is white. There are two pins in each connector. Pin 1 is on the bottom while pin 2 is at the top of each connector. You will jumper pin 1 (bottom) of the black connector to pin 1 (bottom) of the white connector. This will replace step 2 in the procedure below which is for a 16 pin connector. Step 1 of course is still used for either type connector. All steps thereafter are followed.

You will find the diagnostic connector located to the right of the ash tray. To access the connector, pull the ash tray out and then slide a cover which is located to the right of the ash tray to the left. This will expose the diagnostic link connector (DLC).

PROCEDURE TO READ CODES:

If your vehicle is a later 94 or 95 model which uses the 16 pin DTC, the procedure utilizing pins 4 and 15 in step 2 are used.

If your vehicle is an earlier 94 which uses two connectors where one connector is black and the other is white, the procedure utilizing pins 1 of each connector in step 2a are used.

1) In this step, you want to turn the ignition switch to the ON position (engine not running).

2) Using the adapter or jumper wire, connect pin 4 of the 16 pin data link connector to pin 15 with the adapter or suitable jumper wire. If you notice, there are two rows of pins with 8 pins on each row. The top row has pins 1-8 counting from the left. The bottom row has pins 9-16, again counting from the left. So, connect pins 4 and 15, but be CAREFUL in your counting of pins and not jumper any other pins.

2a) Connect the bottom pins (pins 1) of the black and white connectors with a jumper wire.

3) The jumper should be connected for about 2-1/2 seconds and then removed.

4) After one blink of the malfunction indicator light (MIL), the first 4-digit diagnostic trouble code (DTC) will be displayed. Appoximately one second later, the MIL will blink the first digit, then pause, blink the second digit, then pause, and so on.

NOTE 1: A blink code of 2-1-1-1 will always be displayed because the ECM only reads the engine speed (RPM) sensor signal when the engine is running. This code will erase itself once the engine is started.

5) Once the first DTC has been displayed, reconnect the adapter or jumper wire for 2-1/2 seconds and then remove it. The second DTC code (if present) will be displayed.

NOTE 2: Record blink codes on paper for later reference. If an error is made reading blink codes, they can be recalled as many times as needed as long as they have not been erased.

6) Repeat step 5 until no more codes are displayed.

NOTE 3: End of blink code display will be identified by 4 long blinks (0-0-0-0).

7) When all codes have been displayed and recorded, turn the ignition key OFF.

PROCEDURE TO ERASE CODES:

1) Connect adapter or jumper wire to the DLC as previously described. The ignition switch is in the OFF position during this step.

2) Switch ignition ON, but do not start engine.

3) Leave jumper connected for at least 5 seconds and then disconnect.

4) Reconnect jumper for 2-1/2 seconds and then disconnect.

5) The first blink code will be displayed.

6) Repeat step 4 to display all blink codes stored in memory until 4 long blinks (0-0-0-0) are displayed.

NOTE 1: All blink codes must be displayed before they can be erased.

7) Reconnect jumper wire for 2-1/2 seconds and remove it. The DTC memory is now erased.

8) Switch the ignition OFF.

NOTE 2: Confirm that the memory has been erased by displaying blink codes. Only blink code 2-1-1-1 should be displayed.

Keep us posted of how it goes in your repairs and with your car in the shop now.

[aaron_m]

I couldn't get the codes using that method. It turns my check engine light on, but nothing comes up when I pull the wire. Just goes blank.

[jetta4j]

do you know where I could find out what a code is/94 jetta

[aaron_m]

Originally Posted by jetta4j

do you know where I could find out what a code is/94 jetta

I took mine into a mechanic that charged something like $20-$30 to find out what the error was. Got lucky and got a used part for free then spent $60 to get it installed.

Found out that the dealership wanted $100 but that also went toward the cost of service. So if the part cost $100 you'd come out even. So you'd only wind up paying for service.

[jetta4j]

so once i get the code from the vehicle i still gotta bring it in to find out what the code means....is there a way to find out what code it is once i pull it, without takin it to a shop? thnx

[aaron_m]

I couldn't get the codes. The code readers at the autozone or kragen didn't work. The one from Snap-On didn't do it. I have a place close by that does nothing but european cars and their code reader cost them something like $6k and another $500 a year to keep it up to date.

VW I thought was a decent deal. $100 to find out what the problem is, which also went toward the repair bill. Both places after getting the code checked to make sure that's what was really the problem.

In my case I needed to replace the distributor. It kept loosing power on me every so often, I'd have the pedal floored just to keep it going at 50mph then the power would suddenly come back.

[jetta4j]

ok, i got the 2-1-1-1 code...and i also got a 2-1-1-3 blink code....does anyone know what the second code is????thnx..any help would be appreciated

[jetta4j]

the 2-1-1-1 code is /no speed signal from engine....this one is on because the engine is off/the 2-1-1-3 is hall effect switch...check your connection at distributer and test for 5 volts at connecter,,good luck