I am debugging an EGR problem with my '07 V50 1.6 diesel.
I first cleaned the EGR, then I replaced the EGR - to no avail.

Looking into this problem more deeply ,I have ascertained that the sensor part of the EGR Value works fine, but I have scoped the PWM drive to the EGR motor and there is nothing there.

So, I guess either there is a wiring fault between the EGR Valve and the ECM
or the ECM itself is defective (blown EGR motor driver).

I'm trying to trace the wires from EGR Valve to ECM.
I attach the relevant part of Volvo wiring diagram.
The 2 ECM pins I'm interested in are labelled B:15 and B:16.
What I need to know is how to find these on the ECM Connector. The Volvo wiring diagrams don't list the ECM pinout as far as I can see and Volvo do not seem to use the standard Bosch pin numbering.

 

Good plan - love to see this kind of logical, systematic troubleshooting.

When I've tried tracing wires into and out of giant bundles, I've used a tracer, .

That's not an endorsement of that particular one (just the first cheap option that popped up on Amazon), but it's the basic form factor you need. Basically, you connect the alligator clip on the transmitter side to the wire you want to trace, and the black clip to a ground, then use the "sniffer" to find it at the other end. I don't think it's likely to cause a problem with the ECM plugged in but it might be easier to trace with it unplugged. Then you can just figure out which of the three cable bundles the suspect wire is in, and then poke around on the pins until you find the obvious "noisy one". The sniffer operates on proximity so you can chase the wire through to the right bundle, but will "get loud" when you touch the right pin.

 

But in my car the ecu is not bosch. Simens or continental, but this is the same ****.