[Awhite243]

Hi all,

I have been chasing an issue for a while now, and unfortunately cannot seem to solve it.

Under low load and constant throttle position, IE crusing, the car surges, boot it and the serging stops. I've have been able to workout that when it's happening the "command egr" value is flucting massively, so I think the egr valve is opening and closing causing the surging.

The only consistent fault on the car is error code 4D87, after doing some digging, the temperature sensor which is in the pipe linking the egr cooler and intake ( bmw 7811200) is reading -40.05°c. I have checked continuity back to the ECU, all fine, but one pin provides 3.3v and the other (I assume should be ground, like the other temperature sensor on the dpf) doesn't not provide a ground. I've tried connecting the two grounds from both temperature sensors and routing the ground to ground through the alternator. Still no joy...

I have also plugged the temperature sensor into the dpf temperature sensor connector, and it gives a reading, I have also tried a new temperature sensor from BMW.

Anyone got any ideas? I don't know if this is going to solve the surging, but it's something which certainly isn't right, my only other thought is that I need a new ECU?

Any help would be gratefully received.

Thanks Austin