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Torque » Torque OBD ECU Scanner » Torque Discussion / Ideas » Toyota AFR Upper and Lower Limits

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Author Topic: Toyota AFR Upper and Lower Limits
merryfrankster2
Member
Posts: 5
Post Toyota AFR Upper and Lower Limits
on: September 12, 2017 (GMT)

It’s been observed that TorquePro displays Measured AFR’s only falling in range [12.08, 18.12]. For actual AFR’s out of this range, the TorquePro displayed value is pegged at the corresponding limit, lower or upper. According to specification, the range for this PID is [12.00, 19.00].

This has been confirmed independently by several individuals with Toyota vehicles with Denso ECU’s from 2005 and later, and discussed on other Forums.

Vehicle models are Rav4, Highlander, Camry, Avalon, with 3.5-liter V6 engine 2GR-FE.

Separate wideband measurements confirm that actual AFR’s do vary out of this range.

Possible sources of error (please help here):

1. PID formula is wrong?

2. ECU internal calculation is wrong?

3. ???

As an aside, these vehicles all possess two AFR sensors, but TorquePro displays only one value for AFR, presumably combined calculated AFR. It is understood this limitation may be due to the ECU. Any updates?

Thank you for any comments or suggestions.
Capp777
Member
Posts: 2993
Post Re: Toyota AFR Upper and Lower Limits
on: September 12, 2017 (GMT)

Have you tried creating your own
custom pids where you can change
the equation as needed?

You will need the correct OBD pid to
read the desired AFR.
merryfrankster2
Member
Posts: 5
Post Re: Toyota AFR Upper and Lower Limits
on: September 15, 2017 (GMT)

Look in order to fix the equation it would be necessary to know what’s wrong with it, and at this point neither me nor anybody else has any clue what is wrong and why it is displaying incorrect lower and upper limits, 12.08 instead of 12, and 18.12 instead of 19. This is supposedly a standard OBD2 PID, not a manufacturer PID. Toyota PIDs are not available.

Capp777
Member
Posts: 2993
Post Re: Toyota AFR Upper and Lower Limits
on: September 15, 2017 (GMT)

I wonder if it is just a scaling
issue. I have wanted to scale
AD Counts before from 0-1024
but Torque always changes to
0-1000.
cintakc
Member
Posts: 1661
Post Re: Toyota AFR Upper and Lower Limits
on: September 15, 2017 (GMT)

AFR is the calculated Torque parameter, this is not a PID OBD
https://yadi.sk/i/sLhVWvRS3MvXpp
Capp777
Member
Posts: 2993
Post Re: Toyota AFR Upper and Lower Limits
on: September 15, 2017 (GMT)

I was thinking AFR from 0-2 was part
of the standard and just scaled accordingly.
(For each O2 sensor in the standard).
cintakc
Member
Posts: 1661
Post Re: Toyota AFR Upper and Lower Limits
on: September 15, 2017 (GMT)

for RAV4 2GRFE 2006
external PID AFR ratio 2144 – value 0-2
if we multiply by 14.6, we get the desired value
Capp777
Member
Posts: 2993
Post Re: Toyota AFR Upper and Lower Limits
on: September 15, 2017 (GMT)

Still wondering if the display min/max
auto scaling is the heart of OPs issues.

Edit:

Maybe just entering display configuration
sub menu and changing MIN/MAX settings
is all that is needed. (A range of seven could
be causing tick label adjustment).
merryfrankster2
Member
Posts: 5
Post Re: Toyota AFR Upper and Lower Limits
on: September 15, 2017 (GMT)

Checking display configuration was my first thought. But this does not change anything on the numerical value displayed.

Please note we are not talking about O2 sensors we are talking about the OEM AFR sensors.

AFR IS INDEED ONE OF THE AVAILABLE PID’S IT SHOWS UP IN GREEN IN THE LIST OF PID’s BUT THIS WOULD DEPEND ON THE VEHICLE NOW WOULDN’T IT.

Capp777
Member
Posts: 2993
Post Re: Toyota AFR Upper and Lower Limits
on: September 16, 2017 (GMT)

So you saying its not a wide band O2
sensor that uses current? GOTCHA.

Good Luck.
merryfrankster2
Member
Posts: 5
Post Re: Toyota AFR Upper and Lower Limits
on: September 16, 2017 (GMT)

No, that’s not what I’m saying.

The AFR sensor is held at constant voltage and the ECU monitors milliamp current calibrated to lambda or AFR.

The ECU then produces a pseudo-voltage number that it puts out on the OBD2 PID.

The specification for the pseudo-voltage is
0.48v >> 12.0 AFR
0.8v >> 19.0 AFR

Supposedly this should be a convention agreed by all users of the OBD2 spec.

I wish you guys would take the time to educate yourselves before spewing nonsense.

Capp777
Member
Posts: 2993
Post Re: Toyota AFR Upper and Lower Limits
on: September 16, 2017 (GMT)

While I don’t doubt what you are saying,
I believe your ECU reads its sensor then
populates the appropriate OBD pids using
OBD’s lambda and voltage/current
standardized scaling.

Sorry you think what I’m suggesting is
nonsense.

You asked for any thoughts and comments
and we gave it.
merryfrankster2
Member
Posts: 5
Post Re: Toyota AFR Upper and Lower Limits
on: September 16, 2017 (GMT)

Have you even read anything that I wrote before responding?
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