Fuel gauge false readings - will OBD2 help?

[pidgeonpost]

I've read a few of the posts on the forum, and it seems that the sender unit may be the cause. Seems the tank has to be dropped if a replacement is needed, but I'm wondering if my phone app Car Scanner might show a code or anything meaningful? It's a friend's car and some miles away. Any clues please? Thanks.

[Sol]

I don't think so, never seen a fault code for a fuel gauge and even if it reads wrong, how would the ECU (BSI) know the difference between a really empty tank and one that just "says" it's empty...

Plus generic scanners can't read the BSI or instrument bus data / codes. Engine stuff only as far as I've seen and I've got every kind of scanner imaginable. Including the app you mentioned (which is actually one of the best Android ones)

It's likely a sender fault, or bad wiring between BSI and sender.

[pidgeonpost]

I don't think so, never seen a fault code for a fuel gauge and even if it reads wrong, how would the ECU (BSI) know the difference between a really empty tank and one that just "says" it's empty...

Plus generic scanners can't read the BSI or instrument bus data / codes. Engine stuff only as far as I've seen and I've got every kind of scanner imaginable. Including the app you mentioned (which is actually one of the best Android ones)

It's likely a sender fault, or bad wiring between BSI and sender.

[pidgeonpost]

Thanks for that - I feared as much. Looks like he's going to have to bite the bullet and take it to the local dealer, which will grieve him greatly.
All the best....

[Sol]

Cheers buddy. A decent regular garage would be able to check it to an extent, though the BSI end will be a mystery to most non Citroen centred places.