OBDII specs

[91TTZ]

I commented in another thread about the OBDII specification and stated that there are different kinds of OBDII specs. I was quickly blasted by fools who claimed that no, there is only ONE OBDII.

Having built an OBDII scanner from scratch I think I have a pretty good idea how it works 🙂

I figured that I might as well help people out instead of arguing against them.

This info may be useful for those who have a 1996+ car and want to build an OBDII scanner themself. You can hook your laptop up to your car and get realtime sensor information error codes, etc.

OBDII info

As you can see, there are five different OBDII standards. If you build a working board that's not compliant to the specific standard that your car uses, it will not work.

The three most popular types are VPW (GM), PWM (Ford) and ISO (Chrysler and Japanese cars). This is usually the case, but not alway the case.

I made the board for my car for about $50. It works fine. I encourage everyone who has a car but doesn't have the money to take it to a mechanic, or someone who just wants to learn how things work, to make one for yourself.

Go here for more info

 

[91TTZ]

By the way, I made a scanner for my 300ZX Twin Turbo also. If you have a early/mid 90's Nissan like a 240SX, 300ZX, Sentra, Q45, Maxima, etc, I can help you build a board to interface with it. I also know where to get the consult connectors, which you'll discover are almost impossible to find.

 

[Pepsi90919]

cool. i'm looking for something that will scan a 95 taurus though.

 

[91TTZ]

You'll have to look up what kind of circuit that Taurus will use. In 1995, some car manufacturers already began switching over to OBDII, while others still used their older standards. By 1996, all had to switch to OBDII.

 

[mAdD INDIAN]

good info.

but do you really need the ODB scanner when the car tells you the codes anyway?

I know for the Maxima, if you turn a screw in a certain direction on the ECU, the Check Engine Light flashes in a pre-determined pattern of pulses. That pattern corresponds to the error code that the ECU is throwing out.

I'm sure that feature exists on other Nissan products.

 

[StageLeft]

Originally posted by: Pepsi90919
cool. i'm looking for something that will scan a 95 taurus though.

Start with the shift key.

Pretty nifty, 91ttz 🙂

 

[91TTZ]

Originally posted by: mAdD INDIAN
good info.

but do you really need the ODB scanner when the car tells you the codes anyway?

I know for the Maxima, if you turn a screw in a certain direction on the ECU, the Check Engine Light flashes in a pre-determined pattern of pulses. That pattern corresponds to the error code that the ECU is throwing out.

I'm sure that feature exists on other Nissan products.

If you just want the error codes you can do it that way. But making an interface circuit will allow you to read the sensors in realtime, change ignition timing, cam timing (in the Z at least), fuel/air ratio, turn off the air conditioning compressor, AC fan, see the steering wheel angle, check the rear wheel steering angle, all sorts of stuff. And you can datalog the results.

Here's a datalog from my Z when I was just in the driveway revving the engine:

Datalog (In MS Excel format)

 

[Vette73]

And if you want just get a TRUE obd2 scanner that works on all specs, like a good one will, and you will not have to worry.

 

[Pepsi90919]

Originally posted by: 91TTZ
You'll have to look up what kind of circuit that Taurus will use. In 1995, some car manufacturers already began switching over to OBDII, while others still used their older standards. By 1996, all had to switch to OBDII.

it has that connector in the engine compartment along with the ABS connector. if you jumper 2 pins, it will do a KOEO test, then you start the engine and do the KOER test. also allows you to do a solenoid check and that sort of thing, but i'm sure you knew all that anyway.

 

[91TTZ]

Originally posted by: Marlin1975
And if you want just get a TRUE obd2 scanner that works on all specs, like a good one will, and you will not have to worry.

I never said that you couldn't buy an OBDII scanner that works on all specs. You're the idiot that tried telling me that there was only one OBDII.

 

[Pepsi90919]

Originally posted by: 91TTZ

Originally posted by: Marlin1975
And if you want just get a TRUE obd2 scanner that works on all specs, like a good one will, and you will not have to worry.

I never said that you couldn't buy an OBDII scanner that works on all specs. You're the idiot that tried telling me that there was only one OBDII.

even i know that's false. i know there's tons of proprietary parameters.

 

[Vette73]

Originally posted by: 91TTZ

Originally posted by: Marlin1975
And if you want just get a TRUE obd2 scanner that works on all specs, like a good one will, and you will not have to worry.

I never said that you couldn't buy an OBDII scanner that works on all specs. You're the idiot that tried telling me that there was only one OBDII.

There is only one true OBD2 spec for SCANNERS. If a scanner cannot scan ALL cars/trucks 96 and newwer then it is not a true OBD2 scanner, but a type scanner.

Now get over yourself.

 

[91TTZ]

Originally posted by: Marlin1975

There is only one true OBD2 spec for SCANNERS. If a scanner cannot scan ALL cars/trucks 96 and newwer then it is not a true OBD2 scanner, but a type scanner.

lol, you just completely made that up.

It's entirely possible to buy a scanner that doesn't support ALL the different OBDII specifications. In fact, if you bought a OBDII scanner in the past 9 years since OBDII was mandated, it probably does not support the CAN bus protocol which has only recently come out.

 

[mAdD INDIAN]

Originally posted by: 91TTZ

Originally posted by: mAdD INDIAN
good info.

but do you really need the ODB scanner when the car tells you the codes anyway?

I know for the Maxima, if you turn a screw in a certain direction on the ECU, the Check Engine Light flashes in a pre-determined pattern of pulses. That pattern corresponds to the error code that the ECU is throwing out.

I'm sure that feature exists on other Nissan products.

If you just want the error codes you can do it that way. But making an interface circuit will allow you to read the sensors in realtime, change ignition timing, cam timing (in the Z at least), fuel/air ratio, turn off the air conditioning compressor, AC fan, see the steering wheel angle, check the rear wheel steering angle, all sorts of stuff. And you can datalog the results.

Here's a datalog from my Z when I was just in the driveway revving the engine:

Datalog (In MS Excel format)

whoa...real time readings from the sensor?? I did not know htat! That would be awesome, I could make a custom program that could show the bargraph of the sensors and what not.

That's awesome!