What does it mean?
P1547 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Boost Pressure Control Valve Short to Ground .
Symptoms
- Check engine light on with the engine dropping into limp mode
- Little or no boost, so the car feels flat and heavy under load
- Uncontrolled boost in some layouts, with a sudden power cut
- Poor pulling power on hills and when the vehicle is loaded
- Smoke under load on diesel engines
- A fuse feeding the solenoid may blow repeatedly
Likely causes
- Control wire chafed through against the engine, a bracket or the turbocharger heat shield
- Shorted winding inside the boost control solenoid
- Oil or water intrusion into the solenoid connector
- Harness pinched or trapped during previous work in the turbocharger area
- Damaged insulation from long exposure to exhaust heat
- Module output driver failed in the shorted state
How to fix it
- Unplug the solenoid and measure the control wire to ground; low resistance with the connector open confirms a harness short
- Disconnect the module connector as well; if the short remains, the module is not the source
- Measure the winding resistance and the resistance from each terminal to the solenoid body
- Inspect the harness along the turbocharger, exhaust and heat shields for the rub point
- Check the fuse and the connector for oil, water and corrosion
- Repair or reroute the harness, or replace the boost pressure control valve if it is internally shorted
- Check that the wastegate or vane actuator moves freely, then verify boost control in live data on a road test