Why won't my 2012 VW Jetta tdi start?

Asked by Jun 17, 2015 at 08:17 PM about the 2012 Volkswagen Jetta TDI w/ Nav

Question type: Maintenance & Repair

The high pressure injection pump failed on my 2012 Jetta tdi so I replaced it and now the engine won't start. I check the fuse and tested both electric fuel pumps to make sure they were good. I primed the fuel system after replacing the pump. When I turn the ignition on I don't hear the fuel pump turn on at all. What could be wrong?

10 Answers

8,265

Check your relays and fuses, Also check the wiring harnesses under the car for daamge.

1,235

Did you replace the fuel filter? What caused your pump failure? If there are metal fragments in the system the injectors may be bad too.

It turned out to be the fuel pump relay.......thanks

1,235

Glad it's resolved. Thanks for posting the solution.

8,265

Keep in mind the 2010 -2014 jettas all have moisture issues in the cabin. So if something like your dash unit or headlights stop working its probably due to the moisture build up inside your car. it ussaly can't be helped and is probly half the reason your relay failed in the first place.

1 out of 1 people think this is helpful.
1,235

Deathjam, what causal issues have you seen to create moisture? I haven't seen water intrusion issues in this generation of Jetta.

8,265

I have seen alot of issues mostly in the dash unit and head light control switches. This causally happens more in the winter time tho. I have a 2012 jetta and during the winter one day i went out o my car and grabbed my sun glasses out of the roof holder and they were all covered in ice.. i was like wtf?? looked up and there was a large patch of condensation in there. in some extreme cases the water freezes and causes the switch to malfunction i had water in my vacuum which tore the seals to pieces and that was all condensation. i even had condensation build up and form water in the engine and get into my oil pan froze and nearly grenaded my engine cause it froze the sucker pipe for my oil up. they had to manually drop the pan and scrape it out on a fresh oil change maybe 2000Km from before that. I do short trips in the winter so the constant hot cold causes this for engine issues. but long runs can cause build up in the cabin regardless. I had a audi 5000 once. the moisture was so bad in the cabin i had to use a scraper on the window and during the summer i called it the sweat box cause it was always stifling and moisture ridden :P but that all said i have answered a number of moisture related issues in jettas and gotten to know most of the problem area's So moisture is usually only a problem during cold weather.

I have another guestion. 2012 jetta TDI, diesel. it will crank over like it should. glow plug light is out like it should be after they warm up. but the engine will not fire. i spray starting fluid in the air horn and it fires right up. i hate using starting fluid because after years in the army I've seen diesels turned into either babies more times then i can remember. can anyone help me out. the pick up pump was replaced on advice of a friend. did not help. fuel pump is good. like i mentioned before it cranks like normal but no fire. runs great after it starts. any one with a clue what i am looking for i should mention that two mechcanic's have looked at it one said computer needs re-flashed? the second said $6500 to replace every wire in the car yeah i called bulls@$t one that one.please help if you can its a beutiful car but it got me at my last nerve.

1,235

May be a good idea to perform a compression test to make sure the engine is internally alright first.

8,265

chris brings up a logical test. I don't know alot about diesles myself but i am sure like most VW cars they require clear air ways and lots of vacum power. So i would check out all the vacum lines and any crank cases hoses.

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