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ztan · 09-13-2015, 05:55 AM

A while ago, I had a look at the A01G disassembly to chase down a RAM value for MAF Voltage.

I had listed a whole bunch of potential RAM addresses from disassembling the sensor pull routines still available and did some logging with them all to trace the Evap pressure sensor ADC pin.

Logging all these for A01G:

Evap pressure sensor from 20(A35) voltage 16 bit value is stored at FFF842F8 and the float value sits at FFF87C7C after scaling.

Scaling:
Multiplier at 0011CC38: 137.62
Offset at 0011CC3C: 253.90

Without a connection to a sensor, the voltage is pulled up and logs ~5V (~940mmHg).

O2S2 from 21(A34) sends a 16 bit voltage value to FFF842FA.

I have not verified for other ROMs but the RAM addresses for the sensor pull bit of code tend to be uniform between calibration IDs that I've looked at.
If I'd known that the Evap pressure sensor line was unused in my car prior to installing my wideband, and knew I already had the RAM address sitting in a file to test, I'd have routed it there.

09-13-2015, 05:55 AM	#5
ztan Senior Member Join Date: Jul 2013 Drives: Toyota 86 Location: Gold Coast, Australia Posts: 311 Thanks: 44 Thanked 358 Times in 142 Posts Mentioned: 60 Post(s) Tagged: 0 Thread(s)	Sensor input RAM address A while ago, I had a look at the A01G disassembly to chase down a RAM value for MAF Voltage. I had listed a whole bunch of potential RAM addresses from disassembling the sensor pull routines still available and did some logging with them all to trace the Evap pressure sensor ADC pin. Logging all these for A01G: Evap pressure sensor from 20(A35) voltage 16 bit value is stored at FFF842F8 and the float value sits at FFF87C7C after scaling. Scaling: Multiplier at 0011CC38: 137.62 Offset at 0011CC3C: 253.90 Without a connection to a sensor, the voltage is pulled up and logs ~5V (~940mmHg). O2S2 from 21(A34) sends a 16 bit voltage value to FFF842FA. I have not verified for other ROMs but the RAM addresses for the sensor pull bit of code tend to be uniform between calibration IDs that I've looked at. If I'd known that the Evap pressure sensor line was unused in my car prior to installing my wideband, and knew I already had the RAM address sitting in a file to test, I'd have routed it there. Last edited by ztan; 09-13-2015 at 06:19 AM.