Canbus wiring diagram?

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Stuart W
Donor 2022
Posts: 50
Joined: 27 Jan 2022, 18:05
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Canbus wiring diagram?

Post by Stuart W »

You may recall my previous posts from over a year ago re what started out as a parking brake failure on a 2015 grand picasso 1.6 exclusive.After the ABS was replaced a whole host of intermittent faults occurred which have since defied the efforts of various Elecrical specialists and several Citroen main dealers.So here I am again with a car that may work for a week or only a few minutes before throwing ip multiple fault lights.The last dealer insisted on swapping the abs again and then was engaged in a series of messages direct with PSA technical when it did not fix the fault.
I have since been lucky?? enough for the fault to actually occur whilst I had the oscilloscope on the canbus and saw the waveform completely screwed up on the can H bus.I have since isolated the fault to a high resistance in the CanH wire between BSI and Engine ECU.The Can L cable is ok.
However when tracing these cables they are different colours at the BSI and ECU ends.They obviously go to another intermediate device or connector en route. Please can anyone provide a wiring diagram to help identify the route the canbus takes? I would dearly love to get this car back on the road again.
Hell Razor5543
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Re: Canbus wiring diagram?

Post by Hell Razor5543 »

The cable may NOT connect to a different device. It is not unknown for cable colours to change (such as may occur when passing through a bulkhead, for example). However, every few inches there will be a code printed on each cable, and THIS code remains the same throughout the length.
Michel
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Re: Canbus wiring diagram?

Post by Michel »

James is correct. He used the codes printed on the wires to complete the wiring for my towbar, on my Citroen C3 Picasso, saving losing my temper..
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GiveMeABreak
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Re: Canbus wiring diagram?

Post by GiveMeABreak »

There will very likely be interconnections along the way, but the code will be the same - I will send you the diagram and codes by email Stuart, so check in a few minutes of this post. This will be of the Injection ECU, but shows all connections to and from it from the various systems.
Stuart W
Donor 2022
Posts: 50
Joined: 27 Jan 2022, 18:05
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Re: Canbus wiring diagram?

Post by Stuart W »

Thanks guys. This is invaluable information.Thanks Marc. Wiring diagram received. It appears that the canbus is connected in and out of the injector unit for the adblue.Does anyone know where this is located on a 2015 grand picasso please?
Stuart W
Donor 2022
Posts: 50
Joined: 27 Jan 2022, 18:05
x 1

Re: Canbus wiring diagram?

Post by Stuart W »

It seems likely that the controller would be with the adblue tank in the rear of the car.Strange that the canbus should run from the BSI all the way to the rear of the car then return back to the front,on a different pair of wires to almost the same area to connect to the engine ECU .Any info very welcome before I tear more of the car apart!😀