Fault codeP0046

MODERATE

Turbo/Super Charger Boost Control Solenoid Circuit Range/Performance

What this code means

Turbo/Super Charger Boost Control Solenoid Circuit Range/Performance.

P0046 is a generic code: it means the same thing on every make. P0046 belongs to family P00xx — Fuel and air metering, auxiliary emission controls. Its page explains how to read a code and groups all its codes by part.

Type of fault

The signal stays within its electrical limits, but its value is not plausible: it does not match what the control unit expects given the other sensors. The sensor may be drifting with age, but it may also be faithfully measuring a real mechanical problem — a leak, a blockage, an air leak. Replacing the sensor without checking does not always clear the fault.

Turbo boost control

The control unit regulates how hard the turbo blows, through a wastegate that lets exhaust gas bypass the turbine, or through variable vanes on many diesels. A solenoid or an electric actuator moves them, and the boost sensor checks the result.

What you notice

Loss of power, limp mode, sometimes the opposite: a surge of boost then a sudden cut. A whistle or a hiss can point to a leaking intake hose.

How to check it

Start with the simple things: split or loose intake hoses and intercooler pipes, and the vacuum hoses of the control solenoid. Then check that the wastegate or vane linkage moves freely; soot often seizes variable vanes on diesels driven mostly in town. In Klaro, the intake pressure under full load shows whether boost rises and holds.

Watch it live in Klaro

With an OBD2 adapter plugged in, these live readings show the part at work, when your car reports them:

Intake manifold pressure
Barometric pressure
Calculated engine load

What to do

Have it checked this week. The car remains usable, but the fault will not clear itself and will fail the roadworthiness test.

Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →

How to read this code

PPowertrain
0standardised code
0Fuel and air metering, auxiliary emission controls
46P0046