Looking to create a simple OBD display and oil pressure monitor

All service info says is it's estimated, doesn't say what factors it uses.
From what I have read by people that have actually watched it it reports some pretty bogus values and thus isn't all that accurate or useful to watch.

I do not, I'd imagine most of the manufacturer specific stuff is proprietary and is only made available to certain people/companies. The only information that they have to make available is the stuff for global OBDII to comply with federal standards.

I know almost nothing about programming languages and very little about coding and formulas so I couldn't begin to tell you how to figure that one out.

 

What I am understanding is:

Battery voltage (256*A+B)/1000

For clarity, translates to ( (256 * RxByte[0]) + RxByte[1] ) / 1000
Showing order of precedence, where A is the high order, and B is the low order.

 

In AT, Engine oil temps are close and following AT temps (AT1)

 

I don't think that syntax would work, but I believe you are correct.

 

Hmm...one would think the engine oil temp would be more closely coupled to the coolant temp rather than the transmission temp. Interesting.

 

I'd like at some point to get the TPMS data as well, since a lot of folks seem interested in monitoring that. But, that can wait....

 

No, it won't work at all.

This is a clarity example, not an operational statement.
It is intended to demonstrate the high order byte (0) * 256, then the low order byte (1) added to the high order value.
I'm thinking the ECU is 8-bit and why it has to resort to 6502 math and serial transmission of values greater than 8 bits.

The hosting app, iPhone or Arduino has no 8-bit limitation, hence the formula calculation.

 

If that is true, it's just silly. In this day and age, 64-bit chips are cheap, and 32-bit ARM chips are really, really cheap. I think a lot of this bit-shifting BS is deliberate obfuscation on the manufacturer's part. Having to pay thousands of dollars to have access to code that should be freely available to the buyer is maddening. But, it is what it is.

 

Of course it is silly.
Penny-wise and pound foolish.

Reminds me of the computer system board capacitor problems of long ago... the bean counters opted for cheap Chinese knock-offs instead of quality Japanese caps.
I recapped a whole lot of system and video cards back in that time... all to save a few pennies per board.

So very, very few vehicle owners will ever access this data, so it seems (another) exercise in foolishness to obfuscate it intentionally.
None of the stupidity coming from Corporate surprises me anymore.
The 8 and 10 speed transmissions come to mind, as all the makes are having problems with them now, according to my shop-owner buddy.

 

LOL.....brother from a different mother...I well remember the Great Capacitor Fiasco. I spent 2 months desoldering and replacing decoupling caps on the outfit I was working for at the time's industrial mainboards.
I could spend hours regaling anyone who'd listen with tales of corporate idiocy. Every place I've ever worked had the Peter Principle in full operation.
Why they (Toyota) has to make these codes, which TBH, maybe 1/100 of 1% of the owners will ever be interested in, top secret proprietary data is beyond me.

 

My 6 AT speed needs 3 planetary gearsets, with the requisite clutches and bands. You'd need 2 more to get 10 speeds, and all have to fit in a practically-sized case means they have to get ever smaller, which increases loads on gears and bearings, and thus heat. Couple that with turbocharged engines putting out more torque and power (for a while, at least) and you have a perfect recipe for disaster.