Ls swap obd-2 connections w/ mpvi2 issues
Hello everyone!
i have just finished figuring out an issue with my MPVI2 that i would like to share as it doesn't seem like the MPVI2 has been out long enough to have many successful troubleshooting posts, or at least not that i could find before being forced to open a service ticket.
i want to start by clarifying HP tuners does NOT have a contact phone number. i personally find this insane - especially after working with a five member staff company supplying wiring harnesses throughout the world and still taking phone calls for orders or issues. the wait time on the service tickets suck but the person (i believe it was Eric) was helpful to clarify questions i had when he did get a chance to reply.
Previous to this incident i was using my MPVI2 to download to the LS PCM with only intermittent issue.
My setup is a fully built 5.7 in a 87 rx-7 utilizing the newer 99-02 pcm with HPtuners software. i got a universal OBD2 port off amazon and wired it in according to their instructions. (1 pin to blue connector pin 58, 1 pin to constant power, and two wires going to ground) this setup worked for roughly 1.5 years and never really had any issues with it besides when my laptop wouldn't let go of a USB device in that port.
Recently, i installed a new wiring setup running off switches that are controlling relays for the sw. 12v for pcm and all the engine electrical as well, and a constant 12v going to PCM constant. Ensure that these wires are properly powered, and verify that the grounds are all connected as well.. all you have to do is remove the red and blue pin locks off the PCM connectors as originally after installing the engine i had forgot one small ground that was holding back HPtuners to connect.
After receiving a third revision of my tune i went to download to the PCM and i got the fateful message "unable to detect vehicle diagnostic protocol"
opened service ticket and we went from there.. hopefully i can save others some time by posting useful tips
-as always, ensure your MPVI2 has been resynced by pressing re sync on the help dropdown menu. you will need to be on the internet for this. use your phone for hotspot or a verizon jetpack if you have one.
- open vcm editor and click help, and then press the blue i button and wait for the messages to show up. It is my understanding that as long as the information about your interface, and the credits available show up, your PC is communicating with the MPVI2. anything past this is solely an issue between communication between the car and the MPVI2. THE MPVI2 SHOULD SHOW AS A SERIAL CONVERTER NOT CHANNELS A/B LIKE THE OLDER ONE. seeing this misinformation on the internet really screwed me up as i was constantly worried about the wrong issue because even after installing the exe drivers, it said serial converter.
- you cannot read the debug file HPtuners requests yourself unfortunately. personally i feel if i had been able to i could have figured out if the pcm was roached quicker or not, as this was my first obstacle i wanted to clear upon troubleshooting.
-if the writing process gets past bootloader download, the MPVI2 is definitely communicating with the car is some manner.
-if your MPVI2 works long enough only to erase the calibration and not upload it thus causing your car not to run, do not freak out. it is almost a good sign.
-my BIGGEST TIP FOR SWAP GUYS RUNNING A UNIVERSAL OBD2 PORT ---- on the universal bits, there are red, black, white, purple, and brown wires. i don't know why they even put all of them on there because they're not used but oh well. the PURPLE wire goes to blue connector, pin 58 which is a dark green wire. i stripped back the purple wire from OBD port for now and pushed it in the terminal cavity. RED WIRE goes to constant power. BROWN WIRE - garbage. Here's where it gets interesting. multiple instructions on wiring the port in told me to ground both the white AND black wires together. DO NOT DO THIS as this was my issue in the long run. i was able to upload before changing wiring even with them tied together but this time the process just wasn't allowing it. ONLY the BLACK WIRE must go to CHASSIS GROUND! not battery ground, not the dirt ground, the CHASSIS ground.
after re-wiring in that obd2 connector everything worked fine.
