I have a problem with concurrent codes like that, they're so often the result of a poor electrical connection. Not sure this is the case now, because of how many things you've already been over on the engine you've likely fixed these issues already by unplugging and replugging things.
The boost sensor error indicates a fault with the response from that sensor. It's not a common failure. It's worth taking it out, cleaning it and reinstalling it to see if that helps.
The exhaust pressure error - my understanding is that this error is because of a mismatch in pressure reading between the exhaust and the intake manifold before the engine is started. Pressures at this time should be identical (which means the return voltage from the sensors is supposed to be the same within a very small margin for error). I'd say either the sensor has failed, or isn't connecting properly. This connection could be the electrical connector to the sensor (which probably only has two wires, one for a positive steady voltage going in, and one to return the adjusted voltage to the ECU). This sensor gets its negative from being earthed on the exhaust. What if your exhaust isn't earthed properly? You can clean the sensor all you like, but until the exhaust is earthed properly you'll continue getting this problem.
Test it (test both like this): check the resistance between the intercooler body and the battery negative (NOT the body, go straight to the source). You should get a very, very low reading. Do the same for the exhaust, should get a very, very low reading. If it's above a couple of ohms, you have an earthing problem. Negative wire to the engine block, maybe? Try attaching another wire from the battery negative to the intercooler, take the truck out and give it some berries. Still get the error? The pressure sensor may need to be replaced.
NOTE: I say intercooler body because that's where the turbocharger boost pressure sensor on the YD25 D40 is. I am not sure where this sensor is on the V9X, but you're chasing the earth point there.
The boost sensor error indicates a fault with the response from that sensor. It's not a common failure. It's worth taking it out, cleaning it and reinstalling it to see if that helps.
The exhaust pressure error - my understanding is that this error is because of a mismatch in pressure reading between the exhaust and the intake manifold before the engine is started. Pressures at this time should be identical (which means the return voltage from the sensors is supposed to be the same within a very small margin for error). I'd say either the sensor has failed, or isn't connecting properly. This connection could be the electrical connector to the sensor (which probably only has two wires, one for a positive steady voltage going in, and one to return the adjusted voltage to the ECU). This sensor gets its negative from being earthed on the exhaust. What if your exhaust isn't earthed properly? You can clean the sensor all you like, but until the exhaust is earthed properly you'll continue getting this problem.
Test it (test both like this): check the resistance between the intercooler body and the battery negative (NOT the body, go straight to the source). You should get a very, very low reading. Do the same for the exhaust, should get a very, very low reading. If it's above a couple of ohms, you have an earthing problem. Negative wire to the engine block, maybe? Try attaching another wire from the battery negative to the intercooler, take the truck out and give it some berries. Still get the error? The pressure sensor may need to be replaced.
NOTE: I say intercooler body because that's where the turbocharger boost pressure sensor on the YD25 D40 is. I am not sure where this sensor is on the V9X, but you're chasing the earth point there.
