OBD-II trouble code
P0236: Turbocharger/Supercharger Boost Sensor "A" Circuit Range/Performance
The boost sensor's signal is present but doesn't make sense — it disagrees with other sensors or doesn't respond the way real boost should.
Quick facts
- System
- Powertrain
- Category
- Fuel & Air
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $100 – $450
- DIY difficulty
- Intermediate DIY
What does P0236 mean?
P0236 is the rationality-check code for boost sensor "A". Unlike a dead circuit (P0235) or a signal pinned low/high (P0237/P0238), here the sensor is producing a signal — the computer just doesn't believe it. Typical triggers: the boost reading disagrees with the MAP or barometric sensor at key-on when all should match, doesn't rise when the wastegate/bypass commands boost, or lags and sticks instead of tracking load.
Range/performance faults have more mechanical causes than pure electrical codes: a kinked, cracked, or oil-filled sensor hose, a blocked sensor port, carbon or oil film slowing the sensor's response, or a genuine boost-control problem making pressure behave oddly while the sensor honestly reports it. The computer usually limits boost while the code is present, so reduced power is the main symptom.
Start with the key-on comparison test (boost, MAP, and BARO should all read close to atmospheric with the engine off), then inspect the sensor's plumbing before replacing anything.
Common causes
- Cracked, kinked, or oil-filled hose to the sensor / blocked sensor port
- Oil or carbon film on the sensor element (slow/skewed response)
- Drifted or failing boost sensor
- Charge-air leak making readings implausible vs. commanded boost
- Wiring with intermittent high resistance
- Actual boost-control fault (wastegate/bypass) being flagged via the sensor
Symptoms
- Check engine light on
- Reduced power / boost limited
- Boost gauge or live-data reading that lags, sticks, or disagrees with MAP
- Hesitation or flat feeling under load
- Possible companion underboost/overboost codes
Diagnostic steps
- 1.Key on, engine off: compare boost sensor, MAP, and barometric readings — all should be within roughly 1-2 kPa of each other.
- 2.Inspect the sensor's hose/port for cracks, kinks, oil, or blockage; clean or replace as needed.
- 3.Watch the boost value respond to a snap throttle and a loaded pull — it should track promptly.
- 4.Inspect the charge-air system for leaks (boots, clamps, intercooler) that make readings implausible.
- 5.Check wiring/connector for high resistance; verify reference and ground.
- 6.Replace the sensor only after plumbing and wiring are verified; retest under load.
Repair cost
$100 – $450
Often fixed with a hose, a cleaning, or a $40-$150 sensor. If a charge-air leak or boost-control fault is the real cause, cost follows that repair instead. Diagnose before buying parts — this code is a plausibility complaint, not a definitive sensor failure.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with check engine light diagnosis preselected. Adjust labor rate and vehicle category to fit your situation.
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.