Technical Description of OBD-II Trouble Code
Generic: Turbocharger/Supercharger Boost Sensor “A” Circuit Low
GM: Turbocharger Boost Circuit Low Input Conditions
Dodge Chrysler: MAP Sensor Signal Too Low
What is the meaning of this code?
This code is a generic powertrain diagnostic trouble code (DTC) that applies to all turbocharged vehicles. It can be found in various vehicle makes such as VW, Dodge, Mercedes, Isuzu, Chrysler, Jeep, etc.
The powertrain control module (PCM) uses a sensor called the manifold absolute pressure sensor (MAP) to monitor boost pressure. Understanding how the MAP sensor works is crucial in explaining the cause of P0237.
The PCM sends a 5 volt reference signal to the MAP sensor, and the MAP sensor sends a variable voltage signal back to the PCM. The voltage signal is high when the boost pressure is high and low when the boost pressure is low. The PCM utilizes the boost control solenoid to regulate the amount of boost pressure generated by the turbocharger, while also using the boost pressure sensor to ensure that the boost pressure is accurate.
This code is triggered when the PCM detects a low voltage signal indicating low boost pressure, despite a high pressure command being sent to the boost control solenoid “A”.
Symptoms
The symptoms of a P0237 code may include:
Due to the increased risk of catalytic converter damage and turbo overboost when P0237 is present, it is important to address and resolve the issue before continuing to use the vehicle.
Causes
Possible causes for this code to be set are:
Diagnostic and Repair Procedures
Prior to diagnosing P0237, ensure that there are no other trouble codes stored in the PCM memory. If there are other DTCs present, they should be addressed first. Any codes related to waste gate control or 5 volt reference can create the conditions necessary for this code to be set. In my experience, the PCM is the least likely cause of this problem. More often than not, it is damaged or burnt wiring near the turbocharger that leads to shorts or breaks in the circuit.
It is always beneficial to check for technical service bulletins (TSB) specific to your vehicle. Your issue may be a known problem with a known solution provided by the manufacturer, which can save you time and money during the diagnosis process.
