I’m trying to understand this:

I’ve been able to read my codes, and shops have been able to read my codes up until lately it seems. I even took to Infiniti couple years ago, and they gave it back to me saying they couldn’t connect to the computer at all. Earlier this week, I heard the same thing from another shop.

I’m just like, this is odd because I have no trouble reading/clearing codes on my android or iPhone device using my $5 “micro mechanic” device. It’s disappointing I keep hearing this can’t connect excuse. But one thing I have noticed: the engine has to be running, in order to connect. And if it doesn’t, it has to be unplugged, and reconnected while running. They making it seem like it’s something wrong with my ECU/ECM: it’s nothing wrong.

Seems these people don’t know how to connect. I tried to get my airbag light turned off: Infiniti did it before, but then another location said they couldn’t connect. Just trying to figure out what to tell them, because they think I’m crazy. I’m like: take my phone: you CAN connect and read it, I have the whole app that reads data and curves, but they act like they’re scared to use it.

Sometimes my car can be picky or finicky to communicate. It will usually only work with generic OBDII protocol, the Infiniti/Nissan specific protocols don't usually communicate.
Infiniti themselves should be able to do it, even if they have to dust off the old Consult I tool. Assuming someone there knows how to use it.

Makes sense. I know the one I use is the option a step above the generic obd. I remember at a dealership in Phoenix couple years back, they told me they couldn’t connect after trying 2 different type of consults.

I hope these places are turning the engine on to read the codes, but I also don’t know if I’m f*** up the communication by using the little device and doing it with the engine on? That’s been the only way to connect. Even on my 2 other vehicles, the engine usually has to be cranked on to read the codes with my little Bluetooth device. Not sure if that’s standard practice with auto shops.

Don't worry about screwing up the bus with your OBD dongle, that won't happen. The problem with early OBD-II cars is that they didn't have true CAN and talked to the port with the K-line, which is a bit-bang format. Consult3+ can't see it, and with Consult2 you need to ditch the "converter" attachment and use either a straight cable to the gray "Consult port" or a modified OBD cable that swaps the K-line on the OBD to the right wires. The latter is usually a problem on '00~'02's where they were transitioning to CAN. So unless a Nissan shop still has a working C2 and an old timer who knows to ditch the converter and use the gray port, they'll end up telling you they can't read it.

VStar knows his stuff. There is software you can buy (nisscan) that will communicate with the car via the gray consult port.
When doing diagnostics I usually start with a key on/engine off code scan and live data. Sounds like it could be a fluke with your software if you have to have the engine running to communicate. That is not the case with my '97.

Thanks much to you both. I’m going to have to copy VStar’s post so I can relay that next time I come across the issue.

So basically on the main OBD port, it needs to be using consult 2 without the converter right?

As for connecting with engine running; I generally find I plug to device in, turn on engine, then do the connection with my phone code reader app. Or I can plug it in while running. But the main thing is, it won’t read if I’m “on”, has to be engine running.

However the auto parts stores haven’t had this issue last time I’ve tried. It’s been awhile, but they usually just had me turn to “on” without turning on engine.

I’m going to try my code reader again also, the be paid version apparently has more features.

98_Q45 wrote: ↑

Tue Oct 03, 2023 11:06 pm

So basically on the main OBD port, it needs to be using consult 2 without the converter right?

On the gray Consult connector, correct. On early stuff, if it has a standard OBD port at all, it usually isn't wired correctly to be able to talk to later Consults. If you look at the LAN diagrams in the FSM you'll see why, the lines will be labeled RX and TX instead of CANH and CANL. It's a bit-bang setup that needs to be read like a K-line, and the Consult converters/VI's can't do that. Only a Consult2 interfaced directly to the gray connector without the converter will get a response.

VStar650CL wrote: ↑

Wed Oct 04, 2023 4:23 am

On the gray Consult connector, correct. On early stuff, if it has a standard OBD port at all, it usually isn't wired correctly to be able to talk to later Consults. If you look at the LAN diagrams in the FSM you'll see why, the lines will be labeled RX and TX instead of CANH and CANL. It's a bit-bang setup that needs to be read like a K-line, and the Consult converters/VI's can't do that. Only a Consult2 interfaced directly to the gray connector without the converter will get a response.

Can’t say I understand any of that lol, but I’m still going to bookmark this all lol. Like I said, I’ve had codes read at auto parts and some mechanics shops normally, but seems the past couple of times, even at the same shop who diagnosed an issue in the past, I’ve gotten the “can’t communicate” excuse. What really got me was when Infiniti in Phoenix couldn’t read it to turn off my airbag light. I saved $179 in diagnostic, but airbag still blinking: 2 years later lol. But another Infiniti in Kansas City was able to turn it off prior to that. Went off for over a year, then came back outta nowhere one morning. So idk wtf.

However, I’m able to connect just fine for the most part, long as engine is running. For example, this is my emissions test that I ran today:



And once again, now wondering if it is 1 or both catalytic converters causing the engine bogging issue because: transmission fluid is squeaky clean, transparent, and filled to proper line, but it’s still bogging down under load and acceleration, and running hot.