Turbo Boost Sensor B Circuit Range/Performance
Code P0240 indicates that the Engine Control Module (ECM) has detected a signal from the turbocharger boost sensor 'B' that is outside the expected range or performance parameters. This sensor monitors boost pressure to optimize engine performance and protect the turbo. A faulty sensor, wiring issues, or actual boost pressure problems can trigger this code.
01. Most Common Causes
- Faulty turbocharger boost sensor B
- Wiring or connector issues (corrosion, damage, loose connection)
- Boost pressure leak (hoses, intercooler, intake manifold)
- Turbocharger mechanical failure (wastegate, vanes)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or limp mode
- Poor acceleration or hesitation
- Excessive black smoke from exhaust
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect boost sensor B and its wiring/connector for damage or corrosion.
Step 3: Test sensor voltage and signal with a multimeter or scan tool; compare to manufacturer specs.
Step 4: Check for boost leaks using a smoke machine or pressure tester.
Step 5: If sensor and wiring are OK, test turbocharger mechanical operation (wastegate, vanes).
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as reduced power and potential turbo damage may occur. Limp mode may limit speed to protect the engine.
How much does it cost to fix?▼
Costs vary: sensor replacement $50-$150, wiring repair $100-$200, boost leak repair $100-$500, turbo repair $500-$2000.