# 2008 MK5 Jetta 2.5l cranks but will not start now.



## AlAmir (Aug 13, 2018)

hello, I have been looking for a solution over the net for sometime now and haven't gotten any closer to getting my car fixed. I will list the issues I have had with my car in order as well as any fixes. I have a MK5 2008 Jetta 2.5l with 190k automatic. I never had any major issues with it other than the normal wear problems.
- 6 months ago I changed both O2 sensors due to the emissions warning light. the light went away after the fix. 
- 3 months ago I hit a raccoon while driving. I replaced the radiator support, front bumper, wheel-well covers, and engine shield. These were the only parts effected from what i can tell. while fixing the cosmetic damage I also flushed the coolant, changed the spark plugs, changed the oil and filter, cabin filter, added fuel injector cleaner to my gas tank, and air filter. the car drove normally without any issues. 
- 2 months. I usually warm my car up every time before i drive it. I went out to start it like normal and in about 10 minutes i came back to it and when i tried to drive off I didnt notice that is was off and radiator fan was running. I tried to restart it, it would crank but not start. I checked the battery and it was low. from what i remember it was round 10%. i didnt check the volts with a multimeter i just hooked it up to the jump pack i had. even after hooking it up to the jump pack i was not able to start it. my friend gave me a lift to work and i picked up a new battery. i replaced the battery that night and my car started right up. i moved it to another part of my driveway that night. i have no warning lights at all from all these issues. the next day i tried to start it up but it only cranked. I checked the new battery with my jump pack and it read at around 50%. so with in about 9 hours half the battery was gone. I recharged the battery and it started right up. before it started the battery was around 12.8v, and when it was running my multimeter read the battery at around 15.5v. i figured the alternator was running. i didnt think i had a starter problem because it started right up and i had never had a hard time starting it. i started think i may have a something draining my battery over night. when i checked how many amps were drawn from the battery when my car was off i found it to be a little less than .8 amps. i checked all the fuse to see if anything was still draining power with the car off and i didnt find anything. i drove the car without issue for about two weeks. i also thought that maybe i had bad gas so i added HEET to my gas tank.
- 1 month ago my car would start and then shut off at different times. sometime 2 minutes after start, 10 minutes, or while driving. i couldnt predict when it would turn off. the battery looked ok still at 12. whatever volts and the alternator still charging it. if my car died i would just restart it. it only shut off once while driving. if i heard my RPM lower i would just give it gas and it would just continue to run normally. when it stalled i added two gallons of gas to it, thinking maybe my gas gauge was broken. it started right after i added gas and disconnected and reconnected the battery. I drive my car atleast 100 miles daily to work. i live a little ways out of town. i changed the crank shaft sensor, coolant temp sensor, fuel filter, and attempted to change the fuel pump relay however the VW dealer near me would not give me the part number for the relay or the price unless i brought my car in to get scanned. what a scam. his words were "we don't know what relay it is we have to bring it in to get looked at."
- less than a month ago i replaced the camshaft sensor and fuel pump. when i open the door i can hear the pump prime but only for about 3 seconds or so. i turn the key and the my cranks but will not start. how is it the more new parts i put on this car the worse it gets. no matter how much i try to start it, it wont start. so i checked for spark, air and fuel. there is fuel at the rail. it looks like the pressure goes up to 58 psi when priming and down to about 54psi when just sitting there. the car starts when i spray starter fluid for about a second then shuts down. i pulled and cleaned the injectors. started to individually test them but i stopped after one. that one did spray.
- 3 days ago i started checking the wire harness to the fuel injectors. i read online that the computer controlled the injectors by pulsing the ground to the injectors. i tried testing with a noid light. i check all five injector plugs and they did not light. i then checked each plug to see if i was getting a ground signal from the ECU which it was only when cranking. THE ONLY THING I AM NOT GETTING IS THE 12V POWER to the fuel injectors. i pulled the wire harness today to check for brakes and found non. i checked every fuse and the all looked fine. i was getting power on each fuse. the only relay slot that seemed different was the one that held this relay #53. it also didnt have power to it. relay 53 in located in my dash under and left to the steering wheel. i also dont feel it clicking unlike the other ones when i start the car. i have a relay and circuit test which i used to test about half the relays. i got the the fuel pump to turn on with it even as i cranked the engine and still it wont run. i also cleaned the the ground and power connections around the engine bay.

how do i get 12v power to my injectors. i am thinking there my be a short somewhere preventing them from getting power. and i am only assuming i have spark because of using starter fluid. i didnt actually visually see a spark by pulling the plugs one by one. either i have a bad relay, a short in the line, or maybe there is some safety feature to protect the engine. like it wont start because i dont have enough power to create spark or maybe not enough fuel pressure? at this point i am ready to give up and stop throwing new parts into this car. any help with trying to get power to the injector would be much appreciated. sorry about the long post


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## AlAmir (Aug 13, 2018)

*checking the harness*

today i will remove the ECU and disconnect the harness. I am guessing at this point but im looking for a red and black wire. the red and black wire at the injector is what provides the 12v power to the injector. does anyone know what the colors of the power wires at the ecu end are? im going to check for breaks and hopefully update later.


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## AlAmir (Aug 13, 2018)

*After Checking the wire harness*

I checked the Harness from the ECU to each injector connector and I had at least continuity for the power and ground connector. so this leads me to believe that the ECU wont turn on the injectors. So what signal is the ECU wait for? is there air in the fuel lines from changing the fuel pump? But i changed the pump due to no start in the first place. but i did change the fuel filter when my car was still running. I changed the filter due to occasional stalling so im not sure if this problem of no start it even connected to the stalling. I am wondering if made the situation worse? At this point i will try to recheck each relay. if i get my ECU scanned will that tell me more than just no communication with TCM?


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## AlAmir (Aug 13, 2018)

*Relay Check*

Just checked all the relays in my car today. I used my car battery and a multimeter. when checking the relays i could hear each one click and i also checked to continuity in each relay while powered. i checked for continuity between pins (86,85) and (87, 30 while powered). so i am back to square one. so i checked each wire from the ecu to the injectors yesterday and they all checked out. originally the problem was that i was not getting 12v positive power to the injectors when cranking preventing the car from starting. i didnt visually check for spark but the car did run briefly with starter fluid. i thought maybe i had a break in the wire to the injectors. i cleaned all the positive wires coming out of the fuse box in the engine compartment. then i cleaned all the ground wires around the engine. when i checked each harness connector to the injectors with test light i found the ground wires supplying the ground from the ecu to each injector when cranking. so atleast the ecu is signally my injectors to switch on via ground signal. again my only problem was not having a positive power which should be supplied to the injectors continuously. Does anyone know were i should start checking for that positive supply. remember i checked the positive wire to each injector from the ecu and found no breaks. i also though i found the power wires going to the ecu from the back of the relay area under my driver side dash. when i moved my hand under there i could see the resistance increase in my multimeter connected to the ecu harness. about four years ago a deer hit my car on the driver front side between the driver door and the front head light. i am thinking if there is a break it might be on that side. i just dont want to take apart this car even more. any suggestions would be appreciated thanks.


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## Ichabod0525 (Feb 11, 2018)

Wiring diagram / ECM pinout diagram is going to be the tool you need. You've done a lot and taken some side trips but it looks like you have narrowed it down to a power problem either with the ECM or harness. I've looked but didn't find anything for you. Anybody have a diagram saved from erWin


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## AlAmir (Aug 13, 2018)

*starting diagram*


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## AlAmir (Aug 13, 2018)

*starting circuit*

trying to post the starting circuit but can't. i can't find a way to post an image to the platform.


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## AlAmir (Aug 13, 2018)

*thanks*

thanks for the input but i am wondering if anything could be stoping the ECU from providing a signal to the injectors like a safety feature? i am just hoping i dont have to strip this car down and test ever wire. I fear that the ECU might be fried and i dont want to replace it. I may take the ECU apart and look for damage. I know it is wishful thinking that I would see a problem with it from the get go but cant hurt to try. maybe the ECU suffered some physical damage that can be visually detected. Are there any recommendations on where to send the ECU for repair or testing? and if repaired will it then work with my immobilizer chip?


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## AlAmir (Aug 13, 2018)

*ECU testing*

I called APR Tuning, AWE tuning, and BBA reman today about testing my ECU. APR and AWE do not test ECUs just flash working ones. I asked if they would be able to tell if my ECU was completely functional if they looked or tested it and the APR rep stated that there can be multiple issues with an ECU that their software or Techs wont detect. AWE tuning rep just said that they cant do anything for me. BBA reman rep told me that they would test the unit for $100 dollars and if a repair would be needed then it would be $500. BBA rep said it would be a cloned whatever that means so i wouldn't have to take the car into the dealer to get reprogrammed. I did a google search for BBB complaints on BBA and didn't find that many. I am wondering if anyone has ever do anything like this to their ECU. last thing i need is to send them a good working ECU and then have them break it. here is link to the BBB page.
https://www.bbb.org/us/ma/taunton/profile/used-and-rebuilt-auto-parts/bba-remanufacturing-inc-0021-100622/customer-reviews


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## Ronny Bensys (Apr 17, 2014)

The ECU should have feedback signal from fuel pump control module. The flow diagram I think should be like this.

Power --> Relay --> Control Module --> ECU --> Injectors 

Did you replace the control module when you changed the pump?


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## Ronny Bensys (Apr 17, 2014)

'Intermittent not starting' is not an issue a software could cause. When the ECU software is bad, it is bad and it cannot recover by itself the next day.

Permanent water leak could cause rust inside the housing but Bosch makes them really good and hermetic. As far as I know Rabbits host their ECUs under the plastic cover under the windshield wiper, like B6 Passats. Right?


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## AlAmir (Aug 13, 2018)

*Control module?*

thanks for the reply. I spent some time online looking for a module that would control ignition or fuel delivery but couldn't find one for my engine type 2.5L. apparently there is one for the 2.0T model only. I researched this when I was looking to replace the fuel pump. when watching youtube videos about replacing the fuel pump i noticed that some videos contained the fuel delivery module attached to the top of the black cover to the fuel pump. wires went into the module and then the module connected to the fuel pump. mine did not have that module or atleast not in close vicinity like the 2.0T models. so what you are saying is the 12V power goes from the battery to the relay switch to the module then to the ecu to control injector power not just the pulse? here is a link i found today https://www.youtube.com/watch?v=ZhmcwSCsnT4
so im guess there must be a control module between the fuel pump and relay circuit. i tried to look up the parts on Deutsche auto parts website and still nothing https://www.shopdap.com/make-model-year/volkswagen/jetta/mk5-2005-5-2010/engine/2-5/repair/fuel.html so does the fuel module send a signal to the power to the injectors? i have already checked for the control grounds to each injector and they were there just not the 12V power. I replaced the crankshaft sensor but now im doubting that it is a good unit. I cant remember if my car started and was stalling after or before i changed the sensor. i could have had a fuel pump issue which turned into a no start issue after replacing the sensor with an Autozone one. i will try to swap it out today with the original to see if my car starts.


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## AlAmir (Aug 13, 2018)

*ECU water damage*

I also thought there might be water damage but when i pulled the ECU i didnt see anything unusual back there like no nests or any broken wires.


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## AlAmir (Aug 13, 2018)

yes you are right about the location. in my 2008 jetta 2.5L the ECU is located between the engine and windshield. under the windshield wipers. must remove the windshield wiper arms and cover. these arms were a huge pain to remove had to rig up an extractor.


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## Ronny Bensys (Apr 17, 2014)

AlAmir said:


> thanks for the reply. I spent some time online looking for a module that would control ignition or fuel delivery but couldn't find one for my engine type 2.5L. apparently there is one for the 2.0T model only. I researched this when I was looking to replace the fuel pump. when watching youtube videos about replacing the fuel pump i noticed that some videos contained the fuel delivery module attached to the top of the black cover to the fuel pump. wires went into the module and then the module connected to the fuel pump. mine did not have that module or atleast not in close vicinity like the 2.0T models. so what you are saying is the 12V power goes from the battery to the relay switch to the module then to the ecu to control injector power not just the pulse? here is a link i found today https://www.youtube.com/watch?v=ZhmcwSCsnT4
> so im guess there must be a control module between the fuel pump and relay circuit. i tried to look up the parts on Deutsche auto parts website and still nothing https://www.shopdap.com/make-model-year/volkswagen/jetta/mk5-2005-5-2010/engine/2-5/repair/fuel.html so does the fuel module send a signal to the power to the injectors? i have already checked for the control grounds to each injector and they were there just not the 12V power. I replaced the crankshaft sensor but now im doubting that it is a good unit. I cant remember if my car started and was stalling after or before i changed the sensor. i could have had a fuel pump issue which turned into a no start issue after replacing the sensor with an Autozone one. i will try to swap it out today with the original to see if my car starts.


I watched youtube video. It shows a basic description of a fuel delivery system. But every engine is different. For instance, 2.5L engines don't have a fuel pressure sensor.

Cannot believe a 2.5 engine do not have a fuel pump control module. It might be that you have an older generation MAF engine. 

There is a two way data exchange between ECU and pump module. The ECU sends a command to pump module, then receives a feedback. Of course, there are other feedback signals from other modules too but it is fortunate that 2.5L's fuel delivery sistem is quite simple. No HPFP, no regulating valve, no pressure sensor, no return line etc.

If you have your engine code, I can check OEM catalogue for you.

Did you scan your car for stored DTCs?


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## AlAmir (Aug 13, 2018)

I never got any engine codes. when i had a hard time starting it i would hear beeping and the fan would turn on and stay on. at this point i would get a warning light when cranking for over 5 to 6 seconds. i didnt pay attention to it because i assumed it was due to the no start issue. when my car did run a couple of months ago when it would stall out i would get the warning light for emissions. after driving for 20mins or so it would go away. also if it stalled out i would see all the gear indicator lights on at the dash. but after driving it would disappear. i got it scanned a few times at autozone once they told my that there was no communication with the transmission control module. i drove it without issue for a few weeks. also once it stalled and after restarting it would drive over 40 mph it was live it was stuck in 1st gear but it only happened once. i am just going to start from the beginning today. ill reinstall the original crank sensor. i will try to watch the tachometer when starting to see if it moves when cranking. i may rent the circuit tester this weekend and look for faults.


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## Ronny Bensys (Apr 17, 2014)

AlAmir said:


> I never got any engine codes.


I mean engine code, like CBTA we have in the latest generation. Is your engine CBT or BGP? It is written on the code label.


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## Ronny Bensys (Apr 17, 2014)

AlAmir said:


> i may rent the circuit tester this weekend and look for faults.


Yes, you might have codes pending in the memory. Scan with a generic OBDII dongle and Torque app. A chinese one will do the job.


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## 07 jetta WBE (Sep 15, 2021)

Hello ; 
So I'm having the same issues as ALAMIR. ALAMIR, did you find a solution for your start but no crank issue??

I've been experiencing same problems with my 2007 vw jetta 2.5 Wolfsburg edition manual transmission.
I drive the car daily to work and about 3 times a week the car would just shut off out of no where. I would pull over and I'd crank it'll start. Then same issue persist for about 2 year's, keep in mind that these 2 years I've lost half my gas mileage has gone down. Instead of getting 400 miles tank, I would hit between 220 280 miles out of a tank. What ALAMIR explains and what he has done to try to find the problem I have done myself with this car but I don't want to give up. ALAMIR thread stopped and I guess he never replied back to thread to what he found. 
He was onto something about the ECM not communicating, but one difference between my jetta to his jetta, his injectors weren't functioning causing a no start, mine on the other hand was the fuel pump. I could not get that dang pump to turn on for nothing. I have been researching for over 4 years now but it has gotten that time for me to let it go. I really want to fix this problem so I could keep it as my secondary vehicle. 
I ha e narrowed it all down to the ECM not communicating with fuel pump. Before I spend the money on ECM, can anyone else reply back to this thread?


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## le0n (Jun 12, 2013)

07 jetta WBE said:


> Hello ;
> So I'm having the same issues as ALAMIR. ALAMIR, did you find a solution for your start but no crank issue??...


if you're driving the vehicle around town, it's not the ECM.

i would first test the battery, then get it scanned with VAGCOM for proprietary codes.

if the battery checks out to be good, check your main ground connections.

it seems to be power related if your car randomly shuts off.

how many miles are on the vehicle?


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## Eddie Santa (4 mo ago)

Im having the same problem that the two above are having, but in a rabbit. Anybody find a solution?


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