Quote:
Originally Posted by fred8601
I was wondering based on the error codes if the TCV could have been at fault?
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If by the TCV you mean the valve on the air box linked to the engine mounts, it doesn't really play a part in performance issues on Euro 4 onwards.
You're not building manifold pressure or rather very little additional pressure is registering so either the MAP sensor is good and simply reporting facts or the MAP is bad and not reflecting what is actually happening.
I would be viewing the operation of the VNT arm which is a mechanical operation moved by an electric servo bolted onto the turbo assembly.
The arm should be able to fully travel in both directions when revving the engine.
The actuator can also be moved remotely using Vida and a Dice or VCX tool.
Vida can also give Volvo specific codes and a list of possible causes and fixes.
If the arm is moving freely and there are no air leaks, manifold pressure should build so suspect the MAP sensor for not registering this.
If a faulty MAP doesn't report the expected manifold pressure, an out of range fault can be recorded.
If the VNT arm is sticking or not moving at all, boost can't build as expected and will trigger an out of range code in which case either the vanes are coked up or the motor actuator is wearing out.
It's also worth noting that the motors can wear out because the VNT is difficult to move so you may have double trouble.
Sometimes going for a drive, holding around 1500 rpm in 4th gear (about 40 mph) then flooring the accelerator to legal speeds then going back to 1500 rpm and repeating several times can be enough to free up the VNT.