Vauxhall zafira (no crank) CAN Bus faults

I used the Carmin pro wiring diagram for this, there is a free version called Carmin std.
hi this Vauxhall was not starting due to a no crank. apparently the starter motor had been tested and it was ok.
I carried out a code read, found no comms to the engine ECU and CAN Bus faults.
I checked the can bus signal at the 16 pin connector and I'd didn't look right.
I disconnect the engine ECU and the can bus signal looked ok.
next I checked for power going to the engine ECU before I blamed it for messing up the can bus signal.
it was missing the power on both thick red/blue power wires, when I gave those two wires power the car would crank and start.
I had a look in the under bonnet/hood fuse box and found corrosion, I cleaned what I could but it didn't improve the car.
I decided to wire in a relay to do the same job as the smart hook.
the car is cranking and starting now.
this shows that a good ECU can mess up a can bus signal if that module doesn't have all of its powers and grounds.
this was missing it's power and the base line on the can bus was pulled down from 2.5volts to just 1 volt.
thanks for watching

[@carmaxo9424]

As usual, Matt, I can learn a lot from you, correct diagnosis, as always, good job 👍

[@kennedysgarage3281]

Well done Matt, I didn’t actually know that no power coming to an ECU would effect the can signal, so once again it’s a school day. Thanks Matt 👍

[@mechanicmatt871]

I thought may be interesting, until I powered it up I was thinking it would be needing an ECU cheers Matt

[@chrisc5739]

Good diagnosis and a decent real world (temporary) fix. You're a clever bloke Matt and thank you for sharing your know how 👍

[@mechanicmatt871]

Thanks Chris

[@adamswire9152]

Damn, you're good!!!! After looking at that trace, then unplugging and plugging ECU back in, I would've junked the ECU. Thanks for the lesson.

[@mechanicmatt871]

Thanks Adam, really glad I powered up the ECU and found the can bus improve before condemning the ECU, Cheers Matt

[@TheGibby3340]

Two words…TOP MAN. I hope your well paid Matt. Yer worth every penny!

[@mechanicmatt871]

Thanks Ian, maybe one day. Cheers Matt

[@sollykhan2385]

Thanks for sharing this video with us all, Matt, this scope of work often confuses and becomes soul destroying, as most mechanics are not quite up to the in depth level, we had a zafira in our shop,which was passed around like a bag of sweets from 1 place to another for 3 years< as a non runner, there were several problems initially with the car,plus a host of others that got 'Donated' by die hards without the technical expertise, apart from missfueling (petrol) in a Diesel, plus Dpf blocked, wrong air mass, a non working Ect sensor, and a damaged crank sensor, the Major Haul was the underhood control module (Fuse Box corroded) but thankfully it got sorted, Customer wasn't particularly grateful ,as he had shelled out a small kings ransom to all the others, plus an eternal wait collectively, but it made it back on the road, without the impending 'GRAVEYARD' that it was scheduled for, Keep up the good work, we do like your ingenuity and alternative mindset, most tech's out there are simply lost when it comes to improvising. Bless 😇

[@chrisi1909]

Best place for a Engine ECU :-) There will never get any Water ! But i never would have guessed that a missing Power would influence the CAN Signals that much ! Nice Work around !

[@romanosautomotive]

Great diagnosis Matt! It's easy to call modules but good you proved this one wasn't a module fault

[@mechanicmatt871]

It's crazy how missing powers messed up the can bus signal. Cheers mate

[@danielgreenbaum8875]

Really great video your knowledge and skill set no money could buy 👍

[@mechanicmatt871]

Thanks for watching and your comment Daniel

[@KLeeson]

Great stuff Matt. Really enjoyed that. Subscribed

[@mechanicmatt871]

Thank you

[@kevinpalmer7452]

Top marks absolutely brilliant Matt.

[@mechanicmatt871]

Thanks for watching and your comment Kevin

[@johnbickle4654]

nice diag matt another good lesson here starting with the basics is paramount . thanks for sharing

[@mechanicmatt871]

Thanks for watching John

[@JohnnysSpeedShop]

Well done Matt, very interesting stuff indeed 😁😁

[@mechanicmatt871]

Thanks Johnny, I found another use for the smart hook with this one.

[@8power0]

I LOVE THIS VIDEO,,, I AM WORKING ON A CAR WITH A NO START AND I THINK IT'S THE FUSE BOX ALSO... JUST WAITING ON THE CUSTOMER TO GET THE FUSE BOX THANKS FOR YOUR TIME!!!!!!!!!!!!!!!!!

[@mechanicmatt871]

Thanks for watching, I'm glad you liked the video. Cheers Matt

[@rayrundell5484]

Excellent video

[@willd4111]

Hope you got well paid for that! Excellent job 👍

[@robertmobileman8304]

Nice one Matt , good fix

[@mechanicmatt871]

Thanks for watching Robert

[@CANDiagnostic]

Top stuff as always

[@mechanicmatt871]

Cheers mate, the diag was the main thing here, I think the owner wants a fuse box when he gets one from eBay

[@Lambros_Stefaneas]

Well done mate Matt.

[@mechanicmatt871]

Thanks for watching Lambros

[@DJ-tn7vj]

Nice fix bro.

[@ehombie]

great video, diag and thanks for sharing! And i think for the custumer a permenant fix...:)

[@mechanicmatt871]

Thanks for watching Erik

[@stephanevaucelles6378]

thanks for video

[@karmagreenock7622]

Brilliant video 👍

[@mechanicmatt871]

Thanks Karma

[@ADDAUTOMOBILESERVICES]

Great finding 👍

[@mechanicmatt871]

Thank you for watching

[@alexanderstefanxandraswedi5835]

Good job sharing

[@jimpetty2961]

nice job thanks for time.

[@mechanicmatt871]

Thanks Jim

[@jamesbarratt593]

Matt I have the same issue. Zafira B and it literally does not crank. The R75 fuse in the pcb board engages a relay to starter. Its grounded by engine ECM. So swapped over ecu lockset with rear electrical centre to try that. £100 ebay. Still same issue. I had plans for checking the ecm wiring powers and grounds tomorrow. Likely the same fault. So if fuse box was changed in engine bay twice and same fault each time, I am thinking the short run of wire to ecm in inner wing might have a break in it.

[@davidwaters5348]

Excellent mate

[@mechanicmatt871]

Thanks for watching David

[@simonedwards5401]

Good video

[@mechanicmatt871]

Thanks Simon

[@alrifainidal]

well done Mate . i am sure u used the wiring diagram to know the 12v wire going to the ECU .

[@mechanicmatt871]

Oh yes it was Carmon pro from the play store. I forgot to mention that.

[@mechanicmatt871]

I've updated the description to say where I got the wiring diagram. Carmin pro has been extremely good. Cheers Matt

[@alrifainidal]

@@mechanicmatt871 i can't find the app i fond Carmon

[@Ianf1x]

For me Good fix if keeps working end of fix if customer just wants old car to run. I am not keen to have relays on side when I add one even knowing this is normal under steering wheel fuse box. I know I say great job on every comment because that what it is😁

[@mechanicmatt871]

Thanks Ian, I'll have to remember that side on relays can cause problems. Thanks for watching

[@sebczajna700]

Hi, good job👍 I had a similar case once. Ecu did not give mass to the main relay, then after disconnecting the battery, I connected togheter main cables +\- of the battery to reset the driver (capacitors). after all, everything is back to normal. can you tell me the name of your device that you used to power the Ecu? Best regards from Poland

[@mechanicmatt871]

That is sometimes all it needs, I used something called smart hook, I don't use it any more I was trying it out to see what it was like, a fused jumper wire would do the same thing. Thanks for watching

[@djadam2766]

Hi I have same fault no comms to nay module, which wires on the ecu plug is +12v and which are ground, any help would be greatly appreciated

[@mechanicmatt871]

Hi what scan tool are you using, which module is it not communication with?

[@sokakutakeda1500]

hi sir good day! I have the same hantek 2d82 auto like you using on this video why on mine can't get a can bus signal all my set up is good the only difference is I don't have a breakout box I installed directly to dlc. or is my time base incorrect? thank you and God bless.

[@mechanicmatt871]

I'm not sure why your hantek is not showing a can signal, I find this works ok for me. Maybe try adjusting the trigger or time scale. Thanks for watching

[@sokakutakeda1500]

@@mechanicmatt871 thank you sir more subscriber to come & God bless to your channel.

[@deanjamesanthony]

I am having the same problem how much is it to get a fuse box coded ? And where ? I am in Manchester And thank you for this your are really good

[@mechanicmatt871]

I don't program modules myself, not sure what they would want at the dealers, what I did here was change the circuit board from one fuse box to the other to get it to start. Thanks for watching and your comment

[@deanjamesanthony]

@Mechanic Matt no problem mine will start if I have jump leads connect to another car but take them off and no crank nothing lol its doing my head in cheers 👍

[@osagieodion4853]

Please I have a problem like this in my ople zafira

[@davesterl]

Fantastic

[@mechanicmatt871]

Thanks Dave. For a minute I was thinking it would be needing an ECU, I'm glad I tried powering up the ECU first. Cheers Matt

[@leehayes70]

Got an issue with my wife’s Zafira. Can’t find anyone with the knowledge to sort it. Desperate!

[@jonny_s14]

Hi matt, I hope you can get this comment. I'm a vehicle mechanic and had a mondeo of my own with the same problem. It wouldn't start, no signal from key crank position to the starter relay. Made my own relay to get it working then later realised my wife had kicked a body connector down at the footwell on passenger side. She had knocked the delphi connector just enough to look like it was on the lock position but it wasn't making a good contact. Eventually I realised this after I was half way through removing the body control fuse box as I was going to try open it for repair or send away for repair believing it was faulty. Anyway the comment I was supposed to make to you, I love your work and I really like your approach to things with electrical faults. For me (14 years in the motor trade) every day is a school day. I have a request. Could you do a walk through video of some of your diagnostic equipment please? As I'd like to buy that tool you had which can give 12v on demand for fault checking wires, also the scope you used and the obd board looks a fascinating piece of equipment. I need to get up to date as my old multi meter and test light clearly are not cutting it anymore 😂 Wishing you all the best and I hope you see the comment. Thanks. Jonny.

[@jonny_s14]

Also the further i search, I may have found this in your videos. Just watching some others now. I do have to ask, do you have a video on how to find a parasitic draw on a battery?

[@DanWallis86]

Ripper Diagnosis.

[@ayoubladjreb2110]

hello. I need your help if it is possible. I have a problem with the speed of a toyota hilux (5 GL engine) which cannot exceed 100 km / h and which does not react well on the 4 and 5 speed