OBD-II trouble code
P0237: Turbocharger/Supercharger Boost Sensor "A" Circuit Low
The boost pressure sensor circuit is reading too low — a signal below the expected window. Despite the 'turbocharger' name, this is a sensor-circuit code: the usual causes are a short to ground, an open or corroded connection, a failed boost/MAP sensor, or a disconnected vacuum/pressure reference. It's worth fixing because the PCM uses boost pressure to manage the turbo, and a bad reading can trigger reduced-power mode.
Quick facts
- System
- Powertrain
- Category
- Fuel & Air
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $120 – $500
- DIY difficulty
- Intermediate DIY
What does P0237 mean?
The boost pressure sensor (sometimes a dedicated boost sensor, sometimes the manifold/MAP sensor) measures the pressure the turbocharger or supercharger is producing in the intake. The PCM uses that reading to control boost, protect against overboost, and adjust fueling and timing. P0237 sets when the 'A' boost sensor's signal voltage stays below the expected range — the circuit-low condition. As with other sensor-circuit codes, the low reading can mean the circuit is electrically faulted and reporting low when boost is actually fine, or the sensor is correctly reporting genuinely low pressure. The name points at the turbo system, but the fault is fundamentally about the sensor's signal, which is why diagnosis is electrical first.
The common electrical causes are a short to ground in the signal wire, an open or high-resistance connection, a corroded or loose connector, a failed sensor, or a lost reference voltage or ground. On sensors that read pressure through a hose, a disconnected, cracked, or blocked pressure/vacuum reference line can also produce a low reading. A genuinely low boost condition — a leak in the intake or charge piping, a wastegate stuck open, or a weak turbo — could make the sensor honestly report low pressure, though performance codes like P2263 more often capture that. The diagnostic approach compares the sensor's reported value against actual manifold pressure and known-good behavior, then checks the circuit. Because the PCM relies on boost data, a low or untrustworthy reading can push the engine into a reduced-power or limp mode to keep the turbo system safe.
For the driver, P0237 can show up as a check engine light, reduced power or sluggish acceleration, hesitation, and sometimes a limp mode that caps boost. Fuel economy and throttle response may suffer. Diagnosis reads the boost sensor live data, compares it to actual pressure, inspects the connector, signal wire, and any reference hose for faults, and verifies reference voltage and ground before replacing the sensor.
Common causes
- Short to ground in the boost sensor signal wire
- Open or high-resistance connection in the sensor circuit
- Corroded or loose sensor connector
- Failed boost/MAP pressure sensor reading low
- Disconnected, cracked, or blocked pressure/vacuum reference line
- Lost sensor reference voltage or ground
- Genuinely low boost from an intake leak or stuck-open wastegate
Symptoms
- Check engine light with P0237 stored
- Reduced power or sluggish acceleration
- Hesitation or flat throttle response
- Reduced-power or limp mode capping boost
- Poor fuel economy
- Boost gauge or live data reading lower than actual
Diagnostic steps
- 1.Read the boost sensor live data and compare it against actual manifold/boost pressure for the conditions.
- 2.Check the signal wire for a short to ground and for opens or high resistance.
- 3.Inspect the connector for corrosion and looseness, and verify reference voltage and ground.
- 4.On hose-referenced sensors, check the pressure/vacuum line for disconnection, cracks, or blockage.
- 5.Rule out a genuine low-boost cause such as an intake leak or stuck-open wastegate.
- 6.Replace the sensor only after the circuit, reference, and actual pressure confirm the sensor is at fault.
Repair cost
$120 – $500
A boost/MAP pressure sensor replacement typically runs $120-$350 with labor. A wiring, connector, or reference-hose repair can be cheaper. If the low reading reflects a genuine boost problem, the cost shifts to that repair — an intake leak fix or wastegate/turbo work, which can be more involved. Confirm whether boost is actually low before replacing the sensor.
Estimate your repair
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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.