Can the can output an automotive computer be read with a scope?

[kinarfi]

Can the can output an automotive computer be read with a scope? Does anyone know what the output pattern would look like and what each bit represents? I assume the output will be a digital set of bits that repeat so they can be read with the proper equipment, and be visible with a scope.
Thanks,
Jeff
just found that it's called On-board diagnostics (OBD)

 

[kinarfi]

https://en.wikipedia.org/wiki/OBD-II_PIDs#Modes

 

[KeepItSimpleStupid]

This https://www.elmelectronics.com/obdic.html might be a worthwhile read.

The protocols have changed over the years from proprietary, to somewhere around 1990 or so and finally to a CAN network.

There's a cheap (Like $15) OBDII to Bluetooth adapter that can be used to attach to available cell phone apps.

The really high end stuff, the the GM TechII scanner, now nearly obsolete, can actually control stuff. The new version requires a subscription and Internet access, 72 or so hour minimum.

The extremely old design had a blink code mode that could be activated. Not any more.

 

[Tony Stewart]

I've got a couple old ELM to serial ports OBDII adapters if anyone is interested. never used.

 

[Ian Rogers]

I've got a couple old ELM to serial ports OBDII adapters if anyone is interested. never used.

I just bought this. Bluetooth adapter.. I downloaded the app... Works extremely well... I have sorted out my son's and his best mate's cars....

For nearly£6... money well saved...

 

[MaxHeadRoom78]

Can the can output an automotive computer be read with a scope?

The protocol is one form of CAN Bus and most of the OBD readers are built around the ELM327 IC.
They are cheap, you have to watch some of the Chinese versions, but there is quite a few free programs around.
Max.

 

[kinarfi]

I have a 2008 Joyner Trooper T2 offroad vehicle with a Chery 1100cc engine and it has a Siemens VDO 5wy5151d‏ ECU ---From China-----

 

[Mikebits]

I just bought a OBDII diagnostic monitor that uses bluetooth and works with my iPhone for about 100 bucks. Pretty useful I might add, fixed my engine light problem. Was a dumb sensor.

 

[Tony Stewart]

The big bucks are not for the ELM based communication, but rather the secret codes which are unique from the common registers.

Each car OEM type sells this data to suppliers of software who are licensed to interpret the numbers into functions.

 

[kinarfi]

I just bought a OBDII diagnostic monitor that uses bluetooth and works with my iPhone for about 100 bucks. Pretty useful I might add, fixed my engine light problem. Was a dumb sensor.

What make of vehicle was that on?

I found the place to hook into my ECU with my scope and it didn't do me any good, I'm thinking that the voltage spikes I was seeing were to tell the scanner it was ready for it to request information. I assume the reader has to "talk" to the ECU before the ECU sends out any data.

 

[dr pepper]

There are diffrent protocols for obd2 on the same connector, pwm, can, ppm, but all of them require a information request (pid) so to answer your question no.
Older obd1 on certain cars had an o/p that was 'scopeable, or even led-able, honda's could flash the check engine light in code to tell you the fault.
Theres a tale that says you can reset faults on some vehicles by grounding pin14, bit I wouldnt try it sounds like an old wives tale.
A usb interaface that has a elm327 chip can be got from china very cheaply.
Common faults if the engine still runs are exhaust gas sensor or wiring fault, cam sensor fault, maf sensor dirty or open, ignition coil pack not confirming spark.

 

[kinarfi]

I talked to Brandon at Joyner-USA and he says our Joyner ECUs have a proprietary code, I guess that means the off the shelf, inexpensive reader won't do the job.
So now what, start buying parts that may or may not be needed? Maybe I ought go buy an new Trooper with the proviso that they through a reader.

 

[KeepItSimpleStupid]

Any help? https://shdidian.en.alibaba.com/pro...NER_OBD_for_China_buggies_utvs_GATOR825I.html

 

[dr pepper]

I'm not saying that isnt the case, however there are directives that state vehicles must comply with obd standards (past 2001 I think), the bus protocols and commands vary between manufacturers however the obd commands and data are sposed to be common across the board.
Is your system a competition system, they are diffrent because they are aftermarket and all the legislation blurb doesnt necessarily apply to them, allthough some support obd2.

 

[kinarfi]

Any help? https://shdidian.en.alibaba.com/pro...NER_OBD_for_China_buggies_utvs_GATOR825I.html

This is a promising lead, thanks, I'm trying to get info from them now,

There are diffrent protocols for obd2 on the same connector, pwm, can, ppm, but all of them require a information request (pid) so to answer your question NO.
A usb interaface that has a elm327 chip can be got from china very cheaply.
Common faults if the engine still runs are exhaust gas sensor or wiring fault, cam sensor fault, maf sensor dirty or open, ignition coil pack not confirming spark.

NO. This is pretty much the answer I've come up with, I may be in a little over my head, what do you mean 'competitive system'?

 

[dr pepper]

You got the message,

Competition systems like dta and weber are aftermarket ecu's, the kind of thing you put in your car when you want to tune it up, competition systems are designed to be tuned with a laptop, whereas manufacturers systems are pretty much closed.

Find out the number of the engine and google it for faults, I've found some pointers doing this a couple of times.

 

[kinarfi]

Got the message and found the message, the scope showed a 5 volt spike somewhere around every 5 μsec (WAG), I figure that's the signal for the reader to start asking for something to read, PID, so to speak.
A friend put an after market unit on his Trooper and got 20+ more horses out of his engine, it was Super Charged too, not just turboed.

 

[dr pepper]

Sounds like a pwm system, can and ppm blurt pulse trains 20 bits or more.

Its not so much the ecu that makes the power, its the fuel and ignition maps, or rather the skill of the tuner making them.

 

[kinarfi]

Any help? https://shdidian.en.alibaba.com/pro...NER_OBD_for_China_buggies_utvs_GATOR825I.html

$499, a bit much for me, even if it works, but after a few of the people I talked to, I think it will.

 

[KeepItSimpleStupid]

The TechII GM scanners are like $3000, USD, but they are the ones that can flash new software and set options, make serial umber agree etc.

One would hope that some functionality is available with a generic scanner. ABS codes are an option I chose for the scanner I have. They were manufacturer specific.