OBDII connections
 

Question on the OBDII connections. The ECU is signaling the CEL and I am trying to get a scanner to work so I can see what the issue is. I am using the cheap bluetooth scanner I have and I can not get it to talk to the ECU. Hopefully someone with a working conversion can help me figure out what pins need to be connected.

I know the following for sure:
4=Ground
16= 12v

The pinout shows 12 and 13 are the CAN + and - respectively but that is not working. My research on the Web has only added more confusion...LOL

does that bluetooth work with other cars? Sometimes the cheap ones are DOA or super flaky.

Where do you see 12 and 13 being CAN high and low? I thought it was standard that 6 and 14 were CAN HIGH and CAN LOW respectively.

I put in my other car and it worked just fine but you are 100% correct.....it was a PITA to get working with my phone. I would go buy a "real" scanner but I live out in BFE and was just trying to get it working with what I have on hand.

So there's probably some confusion stemming from 2 highspeed GMLAN's being output to the OBDII connector.

6 High, 14 Low - This is the SAE standard. This is the one you need to run the wires from the ECU to.
12 High, 13 Low - Optional Additional from GM

https://www.miataturbo.net/attachmen...ine=1465526198

That is from the OBDII pin out for an LFX Camaro. everything else has been 100% in the wiring diagrams so I trust it personally.

WHy not just use the scanner function built into hp tuners?

OK....I will try those now. Are there any other wires that are needed?

Sorry for spamming your build thread but I was hoping this would help the next guy...

I had V8R program the ECU so I do not have HPTuner...yet. I am hoping to install an e85 sensor and upload a table down the road but for now I just want to see what the LFX is complaining about.

Power and ground(s). 16, 4 + 5. https://developer.mbed.org/media/upl...GdyXCBV7-t.jpg

Leafy - I'll need to post an update about it, but the Torque app saved my ass last week. Besides - you'll need the proper pins to get Hptuners to work as well. :)

Still no joy.... Forgive my ignorance but is there a difference in an error code reader and a full blown scanner as it relates to interface ports on the OBDII? I ask because I am wondering if the scanner is looking for serial data on pin 2 to establish the OBDII interface connection rather than just talking to the ECU via CAN Bus the way something like HPTuners may do.

O well.... I will research a bit tonight and try again tomorrow.

Nope - 4, 5, 6, 14 and 16 are the only ones we have hooked up. The other pins, like J1850, are non-canbus based OBDII protocols. OBDII has been standardized since 96, CANBus as the primary OBDII protocol wasn't established until 2008.

I found it....

As you like to call them gooflophaze..."pro tip":

If your harness happens to be out of an auto the transmission has an internal loop that goes to and from the ATX-Q8 connector. Fell back on the good old rule of "when in doubt...ohm it out". 1 unloomed ECU harness and 2 hours later I now have a working OBDII port.

12 and 13 are only used if the vehicle has a chassis expansion communication bus. I pulled up a 13 camaro wiring diagram and the only modules on that bus are the abs, power steering, steering angle sensor, suspension control module, and multi axis sensor.

If someone could verify that they have 12v on pin 5 of their MAF plug (pink/blk) I would greatly appreciate it. It looks like it should have voltage via the schematics but I'd like to verify before I just start throwing 12v to something.

All of my error codes are linked to the multi-function MAF sensor and again I traced the wire back to the transmission plugs that went to the auto. I guess I would STRONGLY advise others doing this swap to just fork out the coin for a standard trans harness if your motor was pulled from an auto.

Pretty much everything pink/blk is fused 12v in GM. It looks like you're looking for F14UA fuse, which is.. maf, iat, vss, fpcm, reverse inhibit solenoid, skip shift actuator.. so it makes sense that it'd shoot to the tranny plug.

Gooflophaze, It's been a while. Did you get all the gauges working?

fyi, I found a controller for the fuel pump. They use the tach signal to detect the engine running, primes and shuts off

Fuel Pump Safety Switch

It's been a while since posting, but I wanted to give you guys still building a little encouragement. Have done a lot of autox since the LFX swap, but finally got around to doing my first track day. Within my group, I was able to keep up with the vettes and 911s, and in the below video was running with a really nice GT40. I couldn't be happier with the setup. Driving the car has been a blast, but it's been a lot of fun talking to people that stop by after each run to check out the car after seeing it on track.

Little traffic in the first two minutes, but after that things open up and get a lot more fun:

Awesome!