Turbocharger Boost Sensor B Circuit Range/Performance
Code P0240 indicates the turbocharger or supercharger boost sensor B is reading outside its expected range or not performing as commanded. The PCM detects a mismatch between actual boost pressure and what it should be, causing the engine to enter failure mode management and operate on default parameters.
What You Might Notice
- Check Engine Light illuminated
- Reduced engine power and performance
- Poor acceleration response
- Lower fuel economy
- Engine running in limp mode
Most Common Causes
- 1
Vacuum line damage
Vacuum hoses connected to the boost sensor may be pinched, collapsed, cracked, or completely broken, preventing accurate pressure readings.
- 2
Faulty boost control solenoid
The turbo boost control solenoid may be stuck, burned out, or electrically disconnected, preventing proper boost pressure regulation.
- 3
Defective boost sensor
The boost sensor itself may have internal failure, poor electrical connection, or be contaminated with debris or moisture.
- 4
PCM or wiring fault
Engine control module corruption, failed circuits, or damaged wiring harness connections to the boost sensor circuit may cause false readings.
How to Diagnose It
- 1
Check Vacuum line damage — Vacuum hoses connected to the boost sensor may be pinched, collapsed, cracked, or completely broken, preventing accurate pressure readings.
- 2
Check Faulty boost control solenoid — The turbo boost control solenoid may be stuck, burned out, or electrically disconnected, preventing proper boost pressure regulation.
- 3
Check Defective boost sensor — The boost sensor itself may have internal failure, poor electrical connection, or be contaminated with debris or moisture.
- 4
Check PCM or wiring fault — Engine control module corruption, failed circuits, or damaged wiring harness connections to the boost sensor circuit may cause false readings.
How to Fix It
- 1
Inspect and replace vacuum lines
Visually inspect all vacuum hoses connected to the boost sensor and turbo control system. Replace any lines that are cracked, pinched, collapsed, or disconnected. Ensure all connections are secure.
- 2
Test and replace boost control solenoid
Use a multimeter to test solenoid resistance and continuity. If faulty, remove and replace the boost control solenoid with a manufacturer-approved unit.
- 3
Replace boost pressure sensor
Remove the boost sensor connector and hose, then unbolt and install a new OEM or quality replacement sensor. Ensure proper seating and electrical connection.
- 4
Check PCM and wiring connections
Inspect the boost sensor wiring harness for corrosion, damage, or loose connectors. Check PCM connectors for moisture or bent pins. Repair or replace damaged wiring as needed, and consider PCM reprogramming or replacement if all sensors test normal.
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