OBD-II trouble code
P0240: Turbocharger/Supercharger Boost Sensor "B" Circuit Range/Performance
SAE J2012 APR2002: boost sensor B circuit range/performance. The Ford hertz test and the GT-R voltage table belong to other codes. The printed pair is RepairPal's boost sensor, scoped to sensor B. Wiring is outside it.
Quick facts
- System
- Powertrain
- Category
- Fuel & Air
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $236 – $273 (turbocharger boost sensor B replacement, parts and labor, RepairPal national average updated 3 September 2026; wiring, the MAP sensor, and the Ford and GT-R windows are outside this pair)
- DIY difficulty
- Intermediate DIY
Browse every code in P0200–P0299, or start from the full code library.
What does P0240 mean?
SAE J2012 APR2002 names P0240 Turbo/Super Charger Boost Sensor "B" Circuit Range/Performance. Section 3.2 is an in-range signal that is wrong for the operating conditions, including a stuck or skewed value. It is not circuit low (P0241) and not circuit high (P0242). The letter B is manufacturer-defined under section 3.8.
The performance numbers that were actually found are attached to other codes. The 1997 Ford PCED diesel pinpoint test D measures 90 Hz to 115 Hz, then 145 Hz ± 10 Hz at 69 kPa (10 psi), for P0236 on a single MAP. GM 11OBDGS2 (2011) compares turbo boost, AIR, and MAP before cranking, with differences greater than 12 kPa or less than 8 kPa, and that row is also P0236. The 2009 GT-R component table, about 2.03 V at 0 kPa and about 2.67 V at +40 kPa, is the bank 1 and bank 2 sensor check under P0237, P0238, P0241, and P0242. P0240 is not in that detection logic.
Using any of those windows as a universal B-sensor pass would convict a sensor the chart does not name. RepairPal's turbocharger boost sensor replacement, updated 3 September 2026, is $236–$273 (labor $80–$118, parts around $155). The printed pair is that national average, scoped to sensor B because SAE J2012 names P0240 boost sensor B range/performance. RepairPal does not label A or B. The MAP average of $201–$242 is a different line. A wiring repair is outside the pair. The Ford frequency windows and the GT-R volt table stay on the codes those documents name. Diagnosis is $125–$183 labor and is separate.
Common causes
- A stuck reading from sensor B that is still inside the electrical range
- A skewed reading from sensor B that does not match the operating conditions
- The sensor-B circuit in range but not correct for the conditions section 3.2 names
Symptoms
- P0240 stored
- A live signal that still moves, which is why section 3.2 is not the open-circuit row
- No hertz limit and no GT-R volt limit quoted as this code's pass
- P0236 stored on a single-MAP Ford, which is sensor A in that book
Diagnostic steps
- 1.Confirm the scan tool says P0240. P0236, P0241, and P0242 have the numbered tests that were found.
- 2.Find the manufacturer's letter assignment before a hose or a sensor is condemned. B is not 'the other bank' unless the diagram says that.
- 3.If the signal is stuck at a rail, leave this page. Circuit low and circuit high are measured with the circuit connected, and they are different SAE rows.
- 4.Do not apply 69 kPa and look for 145 Hz unless the book in front of you is the 1997 Ford P0236 test. Do not look for 2.67 V at +40 kPa unless the book is the GT-R table for the codes it lists.
- 5.The dollar pair is the boost sensor, scoped to sensor B. Wiring and the $201–$242 MAP average are outside it. The 145 Hz window and the 2.67 V point stay on the codes that print them.
- 6.Verify with the VIN's performance monitor, engine in the state that monitor uses. A key-on reading can miss a skewed-under-boost case, and a boost pull can miss the 11OBDGS2 stopped-engine comparison.
Repair cost
$236 – $273 (turbocharger boost sensor B replacement, parts and labor, RepairPal national average updated 3 September 2026; wiring, the MAP sensor, and the Ford and GT-R windows are outside this pair)
RepairPal's turbocharger boost sensor replacement, updated 3 September 2026, is $236–$273 (labor $80–$118, parts around $155). The printed pair is that national average, scoped to sensor B because SAE J2012 APR2002 names P0240 Turbo/Super Charger Boost Sensor "B" Circuit Range/Performance. Section 3.8 leaves the letter to the manufacturer. RepairPal's estimator does not label A or B. The 1997 Ford PCED frequency steps and the 2011 11OBDGS2 pressure comparison are P0236. The 2009 GT-R table, about 2.03 V at 0 kPa and about 2.67 V at +40 kPa, is filed under P0237, P0238, P0241, and P0242. Wiring is outside the pair. MAP sensor replacement is $201–$242 and is outside. Diagnosis is $125–$183 labor and is separate.
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DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.