EGR Off on PSA EDC16C34

[JeanLuc38]

Hello,

I just tested successfully a technique to make an EGR OFF on a PSA edc16c34. It does not use standard technique of hysteresis but rather patches the AirCtl_nMin_C to 6000 (0x1770) rpm.

The code bellow finds successfully the address in a map dump of the AirCtl_nMin_C variable on my whole dump collection.

private void findEGRLimit() {

// Try to find address of AirCtl_nMin_C (Engine speed threshold for EGR shut-off, in rpm)
// Search for address of AirCtl_nMaxHi_C/AirCtl_nMaxLo_C (We assume that the difference
// between this 2 values is 200RPM or 250RPM)
// Immediately follow AirCtl_nMin_C
// Standard values for AirCtl_nMin_C are 650 or 700 RPM

boolean eos = false;
int start = 2600;
int diff = 200;
while(!eos) {

int hMaxHi = (start+diff) >> 8;
int lMaxHi = (start+diff) & 0xFF;
int hMaxLo = start >> 8;
int lMaxLo = start & 0xFF;

egrLimitAdd = search(0x1C0000,toByte(new int[]{hMaxHi,lMaxHi,hMaxLo,lMaxLo}));

if(egrLimitAdd!=-1) {

egrLimitAdd += 4;
egrLimit = ((((int) memory[egrLimitAdd]) & 0xff) << 8) + (((int) memory[egrLimitAdd + 1]) & 0xff);
eos = egrLimit == 700 || egrLimit == 650;

if( !eos ) {
// Try a second match
egrLimitAdd = search(egrLimitAdd,toByte(new int[]{hMaxHi,lMaxHi,hMaxLo,lMaxLo}));

if(egrLimitAdd!=-1) {
egrLimitAdd += 4;
egrLimit = ((((int) memory[egrLimitAdd]) & 0xff) << 8) + (((int) memory[egrLimitAdd + 1]) & 0xff);
eos = egrLimit == 700 || egrLimit == 650;
}
}

}

if(!eos) {
start += 50;
if(start>=3600) {
diff += 50;
if(diff>250) {
// Fail !
eos = true;
} else {
start = 3000;
}
}
}

}

}



}

[nbtechnic]

hello, what computer language do you use to create these lines of code please?
because your method is not accessible to everyone I think, but it's very interesting!

[JeanLuc38]

it is a java code.
You can find the dump reading code and more in my OpenSource DTC controller project.
https://github.com/JeanLucPons/DTCController