P0237 is a generic OBD-II trouble code that indicates the engine control module (ECM/PCM) has detected a lower-than-expected signal from the Turbocharger Boost Sensor A circuit. The problem may be caused by a faulty boost sensor, wiring problems, poor electrical connections, or an issue affecting the sensor signal.
What Does P0237 Mean?
P0237 means that the ECM/PCM is receiving a boost pressure sensor signal that is below the expected range. The boost sensor monitors pressure in the intake or charge-air system and sends a voltage signal to the engine computer.
When the signal remains too low, the ECM/PCM may set P0237 and turn on the Check Engine Light. Depending on the vehicle, the engine may also reduce turbocharger boost to protect the engine and turbocharger system.
P0237 Symptoms
- Check Engine Light is on
- Reduced engine power
- Poor acceleration
- Low or inconsistent turbo boost
- Engine hesitation
- Reduced fuel economy
- Limp mode on some vehicles
- Turbocharger performance problems
Common Causes of P0237
- Faulty turbocharger boost pressure sensor
- Short to ground in the sensor signal circuit
- Damaged or corroded wiring
- Loose or damaged electrical connector
- Incorrect sensor reference voltage
- Poor sensor ground
- Intake or charge-air system problems
- ECM/PCM fault in rare cases
How to Diagnose P0237
Start by confirming the code with an OBD-II scanner and checking whether other related trouble codes are stored.
1. Inspect the Boost Sensor
Locate the Turbocharger Boost Sensor A and inspect the sensor, connector, and surrounding area for physical damage, oil contamination, corrosion, or loose terminals.
2. Check the Wiring
Inspect the wiring between the boost sensor and ECM/PCM. Look for broken wires, damaged insulation, short circuits, or wires contacting the engine or chassis.
3. Check Sensor Power and Ground
Using a digital multimeter, verify the sensor reference voltage and ground circuit. Many pressure sensors use a 5-volt reference, but the actual circuit design and specifications vary by vehicle.
4. Check the Signal Voltage
Measure the boost sensor signal according to the manufacturer's specifications. A signal that remains abnormally low can indicate a shorted signal wire, faulty sensor, incorrect power or ground, or another circuit problem.
5. Compare Scan Data
Use the scan tool to monitor boost pressure or manifold pressure data. Compare the sensor reading with actual engine conditions and the manufacturer's specifications.
P0237 Wiring and Signal Flow
Note: Sensor pinouts, wire colors, reference voltages, and signal ranges vary by vehicle manufacturer and model. Always verify the wiring diagram and specifications for the specific vehicle.
How to Fix P0237
The correct repair depends on the cause found during testing. Possible repairs include:
- Repairing damaged wiring
- Repairing or replacing damaged connector terminals
- Restoring the sensor ground or reference circuit
- Replacing the faulty boost pressure sensor
- Repairing related intake or charge-air system problems
- Diagnosing the ECM/PCM if all other circuits and components test correctly
Do not replace the boost sensor before checking its power, ground, signal circuit, and wiring. A wiring fault can produce the same code as a defective sensor.
P0237 Repair Cost
The repair cost for P0237 varies considerably depending on the vehicle and the actual cause of the fault.
- Electrical diagnosis: approximately $50–$150
- Wiring or connector repair: approximately $50–$300
- Boost pressure sensor replacement: approximately $100–$300
These are general estimates only. Labor rates, vehicle design, parts prices, and the required repair can significantly change the final cost.
Can I Drive with P0237?
You may be able to drive for a short distance if the vehicle runs normally and has no significant loss of power. However, P0237 can affect turbocharger boost control and engine performance.
If the vehicle has severe power loss, enters limp mode, produces unusual turbocharger noises, or shows other serious symptoms, avoid continued driving until the problem is diagnosed.
Common Repair Mistakes
- Replacing the boost sensor without testing the circuit
- Ignoring the sensor ground
- Failing to check the 5-volt reference circuit where applicable
- Overlooking damaged connector terminals
- Assuming every P0237 is caused by the turbocharger itself
- Ignoring additional stored trouble codes
Recommended Diagnostic Tools
- OBD-II diagnostic scanner
- Digital multimeter
- Vehicle wiring diagram
- Back-probe test leads
- Smoke tester for related intake/boost leaks when required
FAQ
Is P0237 a serious code?
P0237 should be diagnosed promptly because it can affect boost pressure control and engine performance. The severity depends on the vehicle and the underlying fault.
Can a bad boost sensor cause P0237?
Yes. A defective boost pressure sensor can produce an abnormally low signal and trigger P0237, but the wiring, connector, power, ground, and signal circuit should also be tested.
What voltage should a boost sensor have?
Many automotive pressure sensors use a 5-volt reference and produce a variable signal, but exact voltage specifications vary by sensor and vehicle. Always use the manufacturer's specifications.
Is P0237 caused by the turbocharger?
Not necessarily. P0237 specifically points to a low signal in the boost sensor A circuit. Electrical faults and a faulty sensor are possible causes and should be checked before condemning the turbocharger.
Related DTC Codes
P0235 – Turbocharger Boost Sensor A Circuit Malfunction: A general boost sensor circuit fault that may involve the sensor, wiring, or electrical circuit.
P0236 – Turbocharger Boost Sensor A Circuit Range/Performance: Indicates that the boost sensor signal is outside the expected range or does not match engine conditions.
P0238 – Turbocharger Boost Sensor A Circuit High: Indicates that the boost sensor signal is higher than the expected value.
P0239 – Turbocharger Boost Sensor B Circuit Malfunction: A fault involving the circuit of Turbocharger Boost Sensor B.