I would suggest to check the ebp tube. When restricted/plugged, I've seen them cause ebp circuit codes. Not because theres a circuit fault, but because the reading can be too high due to exhaust pressure trapped in the tube.
To test, I remove the ebp sensor from the tube and leave it connected to the wiring harness. This will make to turbo vanes go to the full closed position because its trying to raise the backpressure. Then check the exhaust flow out of the tube, should be a good flow of exhaust out of it.
