Looking at the description the new one is for a P80 chassis car up to 2000, and the C70 that runs to 2002, there were changes in the 03-04 last of the P80 C70's. Your car as an XC70 from 2001 is a P2 chassis. I don't believe the unit you bought is the correct one. If you connect the ETM and switch o...

the etm plug and wiring, it is the common failure point when disconnected and reconnected, it should be replaced. Volvo sells the wiring harness with plug. Pull the intake to connect. https://www.fcpeuro.com/products/volvo-throttle-body-wiring-harness-pigtail-genuine-volvo-31409380?ads_cmpid=1430870...

Step 1 unplug the VVT solenoid connector and see if it still idles badly.

Thank you friends! It makes me happy to receive help from a community based all over the world Does anyone have repair documentation? It would be to know the compression values ​​🫣 I'll keep you informed ! 9:1 Life would be hundred times easier if you install VIDA and get J2534-compatible code read...

Ahem, the compression of a healthy B5244S/S2/SG/S6 engine should be 180 psi at least. Those are naturally aspirated, for turbo I'd imagine slightly lower than this. The most important thing is to check for evenness in compression, you don't want to see more than 5% difference between any cylinder.