P0237

What P0237 Means

Code P0237 indicates a low signal from Boost Sensor A. The boost pressure sensor measures intake air pressure downstream of the turbocharger and sends that signal to the engine control unit (DME). The DME uses it to calculate fuel delivery and control turbo operation.

A low signal can come from a failed sensor, damaged wiring, or a poor contact in the connector. The boost system includes the turbocharger, intercooler, intake charge pipes, and the boost pressure sensor. When the signal falls outside the allowed range, the DME sets the fault and may enter limp mode, limiting engine power.

Symptoms

• Loss of engine power, especially under load.
• Boost system faults with a warning on the instrument cluster.
• Possible engine speed (RPM) limitation and slower acceleration.
• Unstable idle or stumbling on sudden acceleration.

Diagnosis and Repair

Step 1: Read the Fault Codes

Use BMW diagnostic equipment (ISTA, INPA) to read the codes and check for related faults.

Step 2: Inspect the Boost Pressure Sensor

Inspect the boost pressure sensor and its electrical connector. Check for dirt, corrosion, or damage. Clean the contacts if needed.

Step 3: Check the Wiring and Connectors

Test the sensor circuit with a multimeter: check wire continuity and look for opens and shorts. Make sure the connections are secure.

Step 4: Replace the Sensor or Repair the Wiring

If the sensor is faulty, replace it. If you find wiring damage, restore circuit continuity or replace the damaged section.

Step 5: Clear the Codes and Verify

After the repair, clear the fault codes and take a test drive to confirm the problem is fixed.

Related Problems

Ignoring P0237 can leave the engine in limp mode with reduced power, higher fuel consumption, and worse emissions. Driving for a long time with a faulty boost pressure sensor can cause the fuel mixture to run rich or lean, which speeds up wear on the spark plugs, catalytic converter, and turbocharger. Fix the fault as soon as possible.