[The_Tok'Ra]

Hello,

Just received a cheap ENET cable from Amazon.

I noted that on Amazon's product reviews somebody stated that their cable did not work at first as there was the wrong value of resistor fitted between pins 8 and 16 on the OBDII connector.

That's the pins top left and bottom left in the image attached. The resistor fitted to mine is 1.5K Ohms, which is the same wrong value the reviewer noted.

Over the weekend I also found this DIY guide that states the value should be between 506 and 560 Ohms, so 510 as that's a value to can buy.

Can anybody else check theirs cable with a ohm/multi meter and confirm that the correct value is 510 Ohms please.

I'd imagine it's the same for both F series and G series cars, but... just checking.

Thanks!

[xenon]

I built a cable for my F series and used a 560 Ohm. Not used on my G21 as there's not anything I'd particulary want to code but I'd assume it's the same.

[The_Tok'Ra]

Originally Posted by xenon

I built a cable for my F series and used a 560 Ohm. Not used on my G21 as there's not anything I'd particulary want to code but I'd assume it's the same.

Thanks Xenon,

I've had a dig around and I don't have any 510 Ohm resistors, but I do have some 560 Ohm ones.

They are 1/2 Watt mind you, so a bit bigger, but I should able to squeeze it in w/o any issues.

They are measuring around 556 Ohms, so one should be fine.

Cheers!

[xenon]

That should fit no problem - if not let me know and I'll post you a couple of 1/4W.

[The_Tok'Ra]

Originally Posted by xenon

That should fit no problem - if not let me know and I'll post you a couple of 1/4W.

Thanks! Should fit fine though, but if not, I'll be sure to let you know

[The_Tok'Ra]

OK so 560 Ohm resistor fitted, no issues there, but while checking that the other pins were wired correctly, I found that pins 4 & 5 on the OBDII plug which are supposed to be ground and are shorted together, were connected to pin 8 on the RJ45. That's the white with blue stripe wire, now tied up out the way.

The other wires were correctly wired, but

[a.summers86]

Would it not have been easier to just buy a new cable : )

[bmnut]

But where would the fun be in that?

[The_Tok'Ra]

Originally Posted by a.summers86

Would it not have been easier to just buy a new cable : )

Nah, I had the resistors at hand, and I solder often, no big deal to change a resistor. The white and blue wire should have been connected to the outer metal sleave on the RJ45 connector, but as I'll be using it with and ethernet to USB-C adapter to my phone anyway, that's not required as the ethernet adapter does not provide a path to ground anyway.

[The_Tok'Ra]

Originally Posted by bmnut

But where would the fun be in that?

Indeed! I'm glad I cheacked the wiring though! Or I could have been

[bmnut]

Originally Posted by The_Tok'Ra

Indeed! I'm glad I cheacked the wiring though! Or I could have been

Way beyond me all this mate!

[The_Tok'Ra]

Originally Posted by bmnut

Way beyond me all this mate!

Repairing fairly simple electronic devices is a part of my job, so this is easy street, but OMG, the wiring on this cable is very poor.

The rest of the wires are going to the correct pins, but they have not followed the proper standards for wiring the ethernet RJ45 plug to the OBD2 plug at all.

If you look closely, you'll notice that the two pairs of wires in mine are the opposite colours to the ones in the YT video I linked to, and not only that, but two of those wires are the wrong way around to, as far as the wiring standards for ethernet cables are written anyway.

But hey, that's what you get when you pay £6 odds for the cable

[bmnut]

Originally Posted by The_Tok'Ra

Repairing fairly simple electronic devices is a part of my job, so this is easy street, but OMG, the wiring on this cable is very poor.

The rest of the wires are going to the correct pins, but they have not followed the proper standards for wiring the ethernet RJ45 plug to the OBD2 plug at all.

If you look closely, you'll notice that the two pairs of wires in mine are the opposite colours to the ones in the YT video I linked to, and not only that, but two of those wires are the wrong way around to, as far as the wiring standards for ethernet cables are written anyway.

But hey, that's what you get when you pay £6 odds for the cable

Absolutely! You see I haven't got much of a clue about that stuff so I'd be the poor unknowing sod who'd have bought that six quid cable, found it didn't work, would have blindly applied my own non-existent knowledge to trying to put it right and probably 'bricked' an ECU!

[The_Tok'Ra]

Originally Posted by bmnut

Absolutely! You see I haven't got much of a clue about that stuff so I'd be the poor unknowing sod who'd have bought that six quid cable, found it didn't work, would have blindly applied my own non-existent knowledge to trying to put it right and probably 'bricked' an ECU!

Thankfully, I've not read any Amazon reviews on this cable that stated that it bricked their ECU, but I think CAN bus is fairly robust.

Most recent reviews just stated the cable didn't work for them.

That said, that blue and white wire that was connected between the OBD2 ground and pin 8 on the RJ45 connector.... That's just wrong!

Though thanfully, pins 7 and 8 are not used and considered not connected in this instance, but still....