T6 Ignition will not turn on engine cranks with no term15 or term30 [Resolved]

[dodge5326]

Hi if anyone could help it would be much appreciated I am all out of ideas, I left my camper parked up on Monday after a 90 mile journey when i came back after approximately 2 hours it would not start. The key turns fine in the ignition but there is no term15 or term30 its as if the battery is flat but when i turn the key to attempt to start it the engine cranks and fires but as soon as I let go of the key it turns off.

I have checked all the feeds to and from the ignition switch and even tried a donor but the fault is still present, I have checked the term15 and term30 relays and all check out fine both where bench tested (coil and contact side). I have also tried to scan the vehicle with VCDS but it reports no faults or no comms due to no ignition feed.

I Have checked all the main fuses under the battery and all the fuses in the cabin fuse box and all check out fine. I have got as far as I can without the relevant wiring diagrams and knowledge of the T6 so I am asking for some well needed advice please LOL. Does the T6 have a general body control unit?

 

[Loz]

It must be a supply fuse.
VIP membership will give you access to fuse and wiring diagrams.
You say under the battery? these?


You also need to give us a bit more detail:
Year and model etc?

 

[dodge5326]

Hi sorry for the lack of info it my first time posting on a forum its a 2019 Reg transporter highline camper. Yeah I've checked the fuses under the battery in the E-Box and all checkout ok .

 

[Loz]

Have you checked the larger fuses at the bottom of the Fuse box C specifically SC38?

 

[dodge5326]

yeah I have checked them, I have just pulled sc38 and checked it again as a precaution checks out all ok, I have got good supply up to the ignition switch and down to the term15 and term30 relays.

 

[Loz]

Have you checked Fuse box B next to the coolant bottle?

 

[dodge5326]

yeah I checked them with a meter initially but I have just pulled them all and re-checked - All ok

 

[Pauly]

I would start checking the actual rails in the fuse boxes and see which rails if any have power then you can start checking what fuse/relay feeds what row of fuses etc and hopefully track it back

 

[Loz]

The staring and then stopping is also what you get with an immobiliser issue, have you tried a different key?
Also are there any warning lights after it stops running?

 

[dodge5326]

thanks for all the help so far much appreciated, yeah i have tried the spare key my initial thoughts were immobilizer but I don't get any dash lights at all when
turning on the ignition.

 

[Loz]

okay so defo power, so if you are 100% confident you have a supply voltage to each fuse and you have measured voltage on both sides of the fuse (using the tiny hole on top of the fuses) then the next thing is to remove the clocks and check the earth terminal behind the dash module.

Whilst you have the dash out, you can check the supply voltage on the plug, (Give me 5 and Ill get the pinouts)

 

[Loz]

 

[dodge5326]

Hi again I want to thank you for you help I have now found the issue!!!! I found that the SC32 fuse was failing under load! I carried out a voltage drop test over the fuse which highlighted the issue after removing the fuse I found it was a non genuine eBay fuse that was very brittle and must have been very poor quality i replaced it with a good genuine fuse and voila away it went it has now started an run every time I have tried it over the past hour, this would have been a pain to find had I not of had the fuse pictures that were supplied by everyone here so again thankyou!!!!

It blows my mind that a 7.5 amp mini blade fuse could cause a non start fault like this lol, this happened after the car was left locked in the heatwave on Monday afternoon I'm not sure if that may have contributed to the fault all I know is its now fixed lol

 

[Loz]

Splendid! SC32 feeds lots of buttons and modules like steering angle, dash, headlight switch, mirror etc.

 

[dodge5326]

Hi all, unfortunately I am having an issue with the same symptoms only this time its not blowing the sc32 fuse with the key inserted and turned to position 2 I have no term 30 to any dash instruments. The dash display lights up with the door open info etc but no ignition lights I have removed and inspected the J329 (term 15 supply relay)
and all ok. The engine even starts intermittently but then instantly shuts of (like you have turned the IGN off)

I have also had the battery out and checked all the supply fuses and the j317 (terminal 30 supply relay) all seem to be ok but still no ignition feed when the key is turned.

I have also tested the ignition switch just to make sure its ok.

I was thinking maybe looking at the j519 (onboard supply control unit) any ideas where this might be?

any help would be much appreciated.

 

[Pauly]

J519 is the BCM, its the brain of the van and is located above/to the right of the pedals