Table of Contents
Error Code P0237 is defined as Turbocharger/Supercharger Boost Sensor A Circuit Low. It’s a generic trouble code which applies to all turbocharged vehicles. Vehicles of different manufacturer and model of course, have different definitions and specifications on troubleshooting and repair.
For generic vehicles for example, they call this error code Turbocharger/Supercharger Boost Sensor “A” Circuit Low.
For GM vehicles, they call it Turbocharger Boost Circuit Low Input Conditions.
For Dodge and Chrysler, it’s called MAP Sensor Signal Too Low.
Some of the vehicle makes that can have this trouble code include, but are not limited to, Chrysler, Dodge, Mercedes, Volkswagen, Isuzu and Jeep.
Error Code P0237 is triggered when the PCM (powertrain control module, also called as ECM or engine control module in some makes) detects an anomaly in the intake boost pressure sensor A input circuit, indicating that is way below the specifications, suggesting a case of short to ground.
The PCM delivers 5V as reference voltage signal to MAP sensor, while the MAP sensor sends variable voltage signal all the way back to the PCM. If the boost signal is high, the voltage signal is expected to be high, when the boost pressure is low, the voltage must be low as well. The PCM uses boost control solenoid to control the amount of pressure produced by the turbocharger, and simultaneously use the boost pressure sensor to verify the correct boost pressure.
When the PCM sees a low voltage signal which indicates low boost pressure, even though there’s a high pressure command sent to the boost control solenoid “A”, the Error Code P0237 will be set.
As with other error codes, Error Code P0237 will trigger the Check Engine light. Other common symptoms include:
- The PCM will turn of the engine turbo boost, resulting to lack of power on the engine
- Shorted boost sensor circuit and can’t register the right amount of pressure to the PCM, resulting in the engine lacking power during acceleration
Error Code P0237 can be caused by multiple of things, such as:
- Internally shorted to ground turbo boost pressure sensor
- Damaged turbo boost pressure sensor A connector, resulting on short to ground
- Shorted to ground wiring of between the PCM and the sensor of turbo boost pressure sensor A
- Defective boost sensor “A”
- Defective turbocharger
- Faulty PCM
How to Check
As with other trouble codes, the P0237 is diagnosed through scanning for the codes and documenting the vehicle’s freeze frame data when the error occurred to verify the problem.
Then, the codes are cleared and checked whether it comes back or not.
Then, they will check the operation of the boost pressure sensor signal and compare it to MAP sensor.
Next, they will proceed to check the turbo boost sensor connector and wiring and looks for any signs of shorts in the harness.
Also, they will look for signs of corroded pins in the connector, as it’s a tell-tale sign of signal circuit shorting.
How to Fix
Fixing Error Code P0237 is quite simple. Some of the most common repair procedures include:
- Internally shorted boost sensor or boost sensor not providing the right input pressure reading to the PCM must be replaced.
- Shorted wiring harness must be repaired, if not replaced. And they must be secured from excessive heat.
- Corroded connections must be cleaned, if not replaced.
- Internally shorted PCM must be replaced
Shorting on the sensor circuit will always cause the PCM to disable the turbo boost. It will only be resolved when the problem is fixed and the code is cleared.
To prevent misdiagnosis, make sure you try disconnecting the sensors if the shorts and code can just go away. Also, check the harness and look for signs of melting from hanging or loose wire looms.