Hey guys,

On this car, the EGR and DPF were disabled, and ever since then it started having problems — it was producing white smoke, shutting off at higher RPMs, and the injectors would start knocking when that happened, and similar issues.

The injectors have been tested and are fine, their codes are correctly entered into the ECU, the turbo has been checked and is good, the fuel pump and the rail pressure sensor are all okay. The previous owner gave up and sold me the car well below price.

When I first heard the story, I suspected a bad ECU flash. I bought an original file and flashed it to the ECU — and that’s when the problems started (I didn’t touch the EEPROM at that point). The car started throwing errors related to EGR, antipollution, ABS, ESP… all kinds of weird faults.

I bought a new EGR (Valeo 700474), but it doesn’t work — errors like EGR copy signal, open circuit, etc. still appear, along with ABS and other faults.

I concluded that the EGR driver in the ECU is faulty, so I bought another ECU — 100% identical by part numbers. I transferred the EEPROM from the old ECU and flashed the original map — same situation.

When I flash the ECU with the modified map (with EGR and DPF off) that was previously on the car, there are no errors until I start driving. As soon as I drive, it throws communication errors (U) with ESP, ABS, etc. — like the ECU is not communicating with any other module over CAN.

At this point, I don’t know what else to do…

I tried using DiagBox to find some kind of BSI reinitialization so it can accept the new ECU, but I can’t find that option. I also read somewhere that you need to put a virgin EEPROM into the ECU and then pair it through the BSI, because each ECU has its own CAN identity, and ABS/ESP modules query the ECU but don’t recognize it.

But I can’t find any useful options in DiagBox anymore, and I’m out of ideas.