OBD2 passenger port to display gauge/sensor info?

[donutholer]

Picked up a ScanGauge 3 (plugs into OBD2) for my ’99 Z3. Tried it on the passenger-side OBD2 port, but it won’t power on or read anything when the car’s running.


Car does have some ongoing electrical issues, so maybe that’s related. I know there’s another diagnostic port under the hood that is more descriptive and for clearing codes, but shouldn’t the passenger port normally show live data like RPM, coolant temp, etc.?

 

[Rudyrov]

Picked up a ScanGauge 3 (plugs into OBD2) for my ’99 Z3. Tried it on the passenger-side OBD2 port, but it won’t power on or read anything when the car’s running.


Car does have some ongoing electrical issues, so maybe that’s related. I know there’s another diagnostic port under the hood that is more descriptive and for clearing codes, but shouldn’t the passenger port normally show live data like RPM, coolant temp, etc.?

But, does the port power up a code scanner with the engine not running and say just ignition turned on?

 

[donutholer]

But, does the port power up a code scanner with the engine not running and say just ignition turned on?

No, nothing as if there’s no power (which may be the case) starting the engine and accessory mode yield the same result, screen still black.

 

[Rudyrov]

That port should have power so you can run a scanner, that's where I would start.
Perhaps a wiring diagram would help.
Open the attached file and using the search feature type in OBD, there is some info there that might help.

 

[donutholer]

i did test briefly, the scan gauge is working, plugged it into another car and turned on immediately.

 

[donutholer]

That port should have power so you can run a scanner, that's where I would start.
Perhaps a wiring diagram would help.
Open the attached file and using the search feature type in OBD, there is some info there that might help.

I'm a really big noob at eletrical stuff, I just downloaded and am looking at a couple of the pages that I think are the OBD2 port, how exactly do I test for power, and what exactly am I looking at? My amateur suspicion is that because my positive battery terminal has some wear and tear, it's causing a lot of electrical glitches. Previously my power windows worked, the dash went out and so did the windows. So im guessing the OBD2 port could be out too.

 

[Rudyrov]

Try a test light.
Sorry but I cant teach you to be a tech, try googling U tube for electrical troubleshooting videos to get a handle on it.

 

[donutholer]

Try a test light.
Sorry but I cant teach you to be a tech, try googling U tube for electrical troubleshooting videos to get a handle on it.

yea absolutely. I'll do some more research. I really appreciate you providing the file, it should be a lot of help.

 

[Rudyrov]

Carefull, get a test light that use an LED or other low current draw bulb to prevent overloading computer circuits.

 

[NZ00Z3]

Is the top on the 20 pin diagnostic port under the bonnet/hood? It needs to be in place for the OBD2 port to work.

 

[donutholer]

Is the top on the 20 pin diagnostic port under the bonnet/hood? It needs to be in place for the OBD2 port to work.

Oh that’s a great note. I’ll have to check, thanks so much for pointing that out. Might not be capped but I think it is. I heard there’s a way to short the connections on the bonnet OBD2 so that you can do everything from inside

 

[colb]

The 16pin obd2 socket inside the car will only read the engine and transmission modules if it has one, the under bonnet round 20pin Pac-man diagnostic socket reads all modules. I have read that bridging some pins in the 20pin socket the 16pin socket will read all modules but never tried that.
You do need a BMW cable changer cable to plug into the round socket so scanner with 16pin can be connected, Cable changers on ebay here

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