P0237: Turbocharger/Supercharger Boost Sensor "A" Circuit Low

P0237 is a fuel system-related diagnostic trouble code classified as moderate severity. When your vehicle's ECU detects this condition, it stores P0237 and illuminates the check engine light.

If your vehicle has triggered P0237, you may notice one or more of these symptoms:

• Check engine light on, often with a reduced power message
• Limp mode with power sharply reduced, often straight away or under load
• Flat, sluggish acceleration with little or no turbo response
• Boost or MAP reading on a scan tool far below normal air pressure with the engine off
• P0236 or P0238 stored alongside, or a MAP sensor code on engines that share one sensor
• Rough running or poor fuel economy while the computer uses a substitute value

Here are the most common causes of P0237:

No - address this immediately. A signal stuck near zero tells the engine computer there is no boost at all, so most engines drop into limp mode or cap power while the computer runs on a substitute value. Drive gently to a workshop, avoid heavy throttle, towing and motorway merging at full load, and do not keep driving for weeks on that substitute value.

Follow these steps to pinpoint the root cause of P0237:

1. Read all stored codes and the freeze frame. If P0299 is stored as well, check whether boost really was low before blaming the sensor. If other sensor circuit-low codes appear together, suspect a shared 5 V supply or ground rather than the boost sensor itself.
2. Switch the ignition on without starting the engine and read the boost or MAP value on a generic OBD2 reader, if your engine reports it. With nothing pressurising the intake it should match the air pressure outside, about 95 to 105 kPa near sea level. A figure close to zero confirms the low signal.
3. Look at the sensor plug: press it until it clicks, then check inside for green corrosion, water, oil and terminals that have backed out of the housing.
4. Follow the harness for chafing or a break where it runs near the turbo, brackets or the charge pipe.
5. With the ignition on, a multimeter should show about 5 V on the supply pin and a good ground. No supply points to a wiring or supply fault, and a good supply with a dead signal points to the sensor.
6. Where the sensor is easy to reach, unplug it with the ignition on and watch the reading. On many engines the computer pulls an open signal line high, so a reading that jumps to maximum shows the wiring back to the computer is intact and the sensor itself is dragging the signal down. A reading that stays near zero with the sensor unplugged points to a signal wire shorted to ground in the harness.
7. After the repair, clear the code and road-test under load, confirming the boost reading rises smoothly and the code stays away.

Repair costs for P0237 vary depending on the root cause and your vehicle. Here are typical estimates:

P0237 behaves differently depending on your vehicle. Select your car below for model-specific causes and known issues:

These codes are often seen alongside P0237 or indicate related issues: