Last post on Nov 10, 2013 at 1:53 PM
You are in the Volkswagen Jetta
What is this discussion about?
Volkswagen Jetta, Sedan
#5845 of 6655 Re: VOLKSWAGEN JETTA CHECK ENGINE LIGHT [bridgeatl]
Nov 02, 2008 (7:05 pm)
I would put MONEY on the fact that your MAF (Mass AirFlow) sensor is failing. There was a "factory extended warantee" on your MAF because VW knew there was a problem with MAF.
BOTH of my daughters 2001 VWs had their MAF replaced for free under this "extended warantee".
Since I have a VagCom , I was able to diagnose their bad MAF. (running lean and/or rich)
One way to help diagnose a bad MAF is to disconnect the electrical wire and drive the car. If it runs better, the MAF is definatly bad.
#5846 of 6655 Re: VOLKSWAGEN JETTA CHECK ENGINE LIGHT [bridgeatl]
Nov 02, 2008 (7:15 pm)
Sparkplugs which are "dark brown and crusty" are NOT considerd "burnt".
A "burnt" sparkplug would be bright white on the tip because everything except the ceramic has burned off of it.
A competnet mechanic can "read" sparkplugs and determine a lot about the condition of an engine. (fuel mixture, rings, valvestem seals, ignintion system, fuel grade...etc)
Too bad there are not many COMPETENT mechanics around anymore.... many of them just hook computer to car and have little clue how to REALLY diagnose a problem. Also, many of them are paid based on HOW MANY PARTS THEY SELL and not by HOW MANY CARS THEY FIX.
I have always wanted mechanics to be paid based on FIXING a problem... (not on TRYING to fix it) 8-)
With that said - If all of your sparkplugs look about the same condition, this DOES NOT point to an ignition nor a mechanical problem and instead points to somthing IN COMMON to all of the cylinders. (MAF sensor, O2 sensor...etc.)
#5847 of 6655 Re: VOLKSWAGEN JETTA CHECK ENGINE LIGHT [bpeebles]
Nov 02, 2008 (7:25 pm)
Hey Thanks!!...I will look into that tomorrow. But I have the manual here and there are apparently two MAF sensors: LOW INPUT and HIGH INPUT
Which one?....and how could you tell?....is there a separate electric wire for both of them?
And What do you mean, "If it runs better..."? Because the car runs fine....it's smooth and shifts consistently for the most part...but the Auto Parts Store Computer Reading was giving the Too Lean/Fuel Injector problem reading.....so how would I do that?.....would I run it without the sensor and see if the Auto Parts store Computer give the All systems Pass Reading (or whatever the technical term for all systems pass)?....Would the computer show the MAF sensor as "CANNOT BE READ" if I disconnect it?....Let me know....thanks....I seriously think this might be the problem.
#5848 of 6655 Re: VOLKSWAGEN JETTA CHECK ENGINE LIGHT [bpeebles]
Nov 02, 2008 (7:31 pm)
Yeah...I will look into the MAF Sensor tomorrow....but if the spark plugs weren't bad....then why has the Check Engine Light gone off and STAYED OFF?....That's what baffled me.....even though the reading on the Auto Parts Store Machine said Fuel Injector problem. I thought long and hard about taking my Jetta to a VW dealer...but it would have been $106 just for a further examination and possible dianosis. I just wasn't sure I was up for that...what with being a College Student and all lol
#5849 of 6655 Re: VOLKSWAGEN JETTA CHECK ENGINE LIGHT [bridgeatl]
by MrShift@Edmunds HOST
Nov 03, 2008 (8:24 am)
Once again, any diagnostic machine is only as good as the person using it. People are throwing parts at your car and hoping that one sticks, sounds like. Not being there, I can't start a "diagnostic tree", but basically such a "tree" is a system of logic wherein the...ahem...technician tests THIS, and if not THIS, then he/she goes to THAT....and if not THAT...and so on, starting from most likely to least likely based on the initial codes from the machine. Each THIS or THAT has a value to be read, or a function to be tested, to eliminate it or accuse it of the crime.
So what i'm saying is that a code that says something like "misfire" or "bad injector" could be caused by many things, and the idea is not to replace all those things at once and then say "see, I solved it" (at the owner's great expense).
#5850 of 6655 Re: VOLKSWAGEN JETTA CHECK ENGINE LIGHT [Mr_Shiftright]
Nov 03, 2008 (10:24 am)
the idea is not to replace all those things at once and then say "see, I solved it" (at the owner's great expense).
But most of us are happier paying for new parts to be installed, than we are paying diagnostic charges, as in:
it would have been $106 just for a further examination and possible dianosis. I just wasn't sure I was up for that
#5851 of 6655 Re: VOLKSWAGEN JETTA CHECK ENGINE LIGHT [jeffyscott]
by MrShift@Edmunds HOST
Nov 03, 2008 (11:21 am)
The thing to do in that case is to work it out so that the diagnostic charges are subject to cancellation if the diagnosis proves to be incorrect.
I'm certainly not going to pay for a wrong diagnosis. I can do that myself
Nov 03, 2008 (11:28 am)
I am having power loss on my 1999.5 Jetta TDI.
The whole story is important here probably. Head needed rebuilding, has new camshaft, timing belt, tensioners waterpump since it was all open. I also had the turbo actuator valve replaced (the bladder gizmo behind the engine). Right after that the turbo worked great, car ran like a dream for about a weak. I then noticed when the turbo would spool when at high RPMs that it would skip and then plop into limp mode. It has gotten progressively worse so that now it will drop off almost from the first acceleration in first gear. It will usually fix when the key is cycled.
when I run the codes I get P0101 an P1550 (regular handheld jobby), and under the the Vag-Com there are also codes for the rear ABS sensors.
So far to fix this issue I have replaced the Turbo Solenoid (up by the windshield with the hoses going to it), I have replaced the MAF....I have taken apart the hoses going to the air filter (all clear). I have visually inspected the vacuum hoses and though a little frayed don't see any breaks. The air filter is relatively new.
The connector plug (that plugs into the MAF) is a replacement plug so it leads me to believe someone looked at replacing that before I came onto the scene. I am thinking I should check to make sure that is wired well...but what else should I try. Any advice, happen to anyone else? I am reaching the end of my wits thinking about it....need some things to check so I feel like I am sniffing out the problem....give me your best shot!
Oh something else you should know. The engine light doesn't work it was somehow disconnected or blown, I wager disconnected so they could sell the car.
#5853 of 6655 '03 Jetta GLI - Coolant always empty and Fans don't turn on
Nov 07, 2008 (2:26 pm)
Prior to my car accident, I did not experience any issues with my car. A almost month after the accident, my coolant light came on. I couldn't even open the hood after the accident. I later got it to open and realized that the coolant tank was empty. Then I thought to myself I haven't heard my fans turn on in a while. Sure enough, the fans weren't turning on. I got my crappy insurance company to come pick up the vehicle and take it to one of the "approved" shops. A month later I pick up my car. I didn't like how they fixed my body kit, but I could deal with that sorta. 50miles down the road, my coolant light came back on. I looked and it was BONE dry. The shop towed my car back and for the first time a mechanic check my car. They call me back saying that there is a pin hole in some hose that has allowed air to get in. They then said it wasn't accident related and that I had to pay to the diagnosis. Is this possible for a pin whole is a hose to cause my fans not to turn on and my coolant to leak out at the point of impact? I just know that my car was in perfect working order prior to the accident, no lights indicating problems and regular check ups. Can someone help me understand please...
#5854 of 6655 Re: Codes P1550 and P0101 [freeantelope]
Nov 10, 2008 (4:38 pm)
The key here is your mention of replacing (the bladder gizmo behind the engine). That may have been a bad idea.
First of all, that thing is called the VNT actuator.
The turbocharger is a VNT (Variable Nozzle Turbocharger) and the adjustment on the 'shaft' of the VNT actuator is tuned at the factory. Altering it can have devastating effects on your engine. (like overboost!)
the code P1550 you are getting is pointing directly at that as the problem ( http://wiki.ross-tech.com/index.php/17958/P1550/005456 )
Essentually, code P1550 is telling you that the computer senses a problem with the VNT actuator or its control piping. Also check your N75 valve.
Here is a website that has excellent photos of the inner-workings of your VNT... pay close attention to the very last moving photo which shows how the VNT vanes move.