My 09 VW Jetta 2.0 TDI has a check engine light, any idea?

Question

I got a letter from VW that my car has a recall. When I called the dealership to book an appointment, they asked me if I have a check engine light on, which I did. So they told me they have to get that over with first before they service the recall. My cousin is also a mechanic and he checked the CEL and told me its nothing to worry about, so I've driven the car for a year with the CEL and haven't had any problems with the car.

This morning I ran into my neighbor who's dad is a mechanic and I told him about the CEL, he told me he has a scanner he can look it up. So I hooked it up to my car and he told me there is a code that says the sparkplugs needs to be replaced. I also forgot to mention that when I drove the car last night, my engine was creating some unusual noise. So I continued to drive it a little bit to see if it would go away, which I think it did almost completely go away.

I haven't been driving the car much due to the pandemic, but my neighbor told me that since it is a diesel engine, they are meant to be driven often otherwise parts will wear out. Not sure if that is true. But can anybody give me some insight on my situation? My car's engine is a 2.0 TDI

Anonymous · Answer

The spark plugs are GLOW PLUGS like an electric range element that gets red hot when you put it on High.  So long as the car starts, then enough glow plugs are working that you do not need to replace them.  When all 4 die, then you will find the car REALLY HARD TO START.  But it still can happen if it is summer.
MAYBE THAT IS WHAT THE CEL sensed. A single dead glow plug. You take it to THEM WHEN THEY WANT IT.  They know more than your cousin. They want you to have a reliable vehicle.

"but my neighbor told me that since it is a diesel engine, they are meant to be driven often otherwise parts will wear out."   You mis-heard your neighbor. Diesels are NOT grocery getters.  They are meant to be driven long hours and many miles.  Thats why the big highway trucks are diesel as they criss-cross the country, and why farm equipment is diesel as they run for days 24/7 on the farm when either plowing or harvesting the crops.  If you just need it to drive 2 miles to work and then the car is shut off for the entire day. THAT IS HARDER ON AN ENGINE THAN CONTINUOUS RUNNING.
"Parts only wear out if they are used.   If the new car sat in the car lot for several years, it is still NEW as no parts were being used running it.  No different than wearing shoes.  If you never wear them then the soles would look like brand new because  they have not been used.

Find out when or IF your cousin or neighbor puts a MILLION MILES ON THEIR GAS POT. You "could" achieve that in a diesel vehicle.  Them...never. Maybe 300K or 1/3 of the distance you could go on the same engine without any repairs except for maybe glow plugs(which are essentially spark plugs for diesels and used on morning starts(cold starts)  That is why you have an "S" knob you pull out all the way and you turn the key slowly till the lights come on and you look for the amber light.  Once the amber light goes OUT then you turn the key farther to engage the starter motor to start the engine.  Only need the glow plugs on cold starts.  Not halfway through the day if you drove to town as the oil is still warm.  Car will start instantly. Once you know how to drive a diesel, you know it is just different on the starting of the diesel.  And the noise it makes.  More like bolts being shook in a tin can.  That is a healthy diesel engine.    In a gas engine, if they heard that noise they need to see a mechanic(not cousin or neighbor)

What the dealership was telling you is that they have 2 jobs to do.  First to get rid of the Check engine light problem  and then they can work on the second issue.
, Why they would even BOTHER to inform you of that, is unknown to me.  It is a repair.  Your car needs it, it needs both issues resolved.  Only the DEALERSHIP SHOP knows WTF they are doing.
. Being so informative is just detrimental to their business.  They should have just done the work.
Your cousin and neighbors are both IDIOTS.  VW has special scanners which is not commonplace domestic car scanners.  The coding is different too.  VW is like that.

The Devil · Answer

You need to go by the trouble code, not gossip. The trouble code has a specific meaning. Diesels do not use spark plugs. Clearing the CEL does not fix the car. The problem needs actual repair.

John Alden · Answer

Diesel engines have glo-plugs, not spark plugs. Gl plugs are only used for starting, so yeah, once it starts and warms up it will sound fine.

jimanddottaylor · Answer

You lost me when the scan said that you should replace the spark plugs on your diesel engine.  Get to the VW dealer and have them scan it and correct it and then take care of the recall.  Then you will know what the problem was and can be assured that it will not return (not soon)

My 09 VW Jetta 2.0 TDI has a check engine light, any idea?

4 Answers