Boost Solenoid: Testing and Inspection

APC Solenoid Inspection:

For electrical inspection of the boost pressure control (BPC) valve, see "Computers and Control Systems."

Caution
Never test the boost pressure control valve by connecting it directly to battery current.

Inspection of Signal Hoses
1 Disconnect all of the BPC valve's hoses; from the turbo compressor, the turbo vacuum and from the wastegate valve's membrane housing unit.

2 Blow into the hose leading from the compressor (C) and ensure that air comes out of the hose to the wastegate valve (W).

3 Also blow into the return hose from the vacuum tube (R) and ensure that air comes out of the hose to the turbo compressor (C).

Inspection of the Boost Pressure Control Valve's Throttling
There is a throttle built into the BPC valve's connection to the turbo compressor (C) which results in this opening being more prone to deposits of dirt, etc., than the others.

Inspect and ensure that the throttle is not restricted. If the hole is too small and the deposits cannot be removed, replace the BPC valve.