P1238 – BMW DTC

BMW DTC P1238 – Secondary Upstream Manifold Air Pressure Sensor Circuit High

DTC P1238 meaning on BMW

DTC P1238 on a BMW indicates a fault with the Secondary Upstream Manifold Air Pressure Sensor Circuit registering a high voltage condition. This sensor is responsible for measuring the pressure in the intake manifold and providing this data to the engine control module (ECM) for proper fuel delivery and combustion control.

BMW DTC P1238 symptoms

Symptoms of DTC P1238 on a BMW may include:

• Check Engine Light (CEL) illuminated on the dashboard
• Reduced engine performance or power
• Engine stalling or rough idling
• Increased fuel consumption

BMW DTC P1238 causes

Common causes of DTC P1238 on a BMW include:

• Faulty Secondary Upstream Manifold Air Pressure Sensor
• Wiring or connector issues in the sensor circuit
• ECM software or hardware problems

BMW DTC P1238 seriousness

DTC P1238 should not be ignored as it can lead to poor engine performance and potential drivability issues. Continued driving with this fault may cause further damage to the engine components and result in costly repairs.

How to diagnose DTC P1238 on BMW

To diagnose DTC P1238 on a BMW, follow these steps:

1. Use a diagnostic scanner to retrieve the fault code and freeze frame data
2. Inspect the wiring and connectors related to the Secondary Upstream Manifold Air Pressure Sensor
3. Check the sensor’s voltage output using a multimeter
4. Perform a visual inspection of the sensor for any physical damage

How to fix DTC P1238 on BMW

To fix DTC P1238 on a BMW, consider the following:

1. Replace the faulty Secondary Upstream Manifold Air Pressure Sensor
2. Repair any damaged wiring or connectors in the sensor circuit
3. Update the ECM software if necessary

How to erase DTC P1238 on BMW

To erase DTC P1238 on a BMW, you can:

1. Use a diagnostic scanner to clear the fault code after the repair
2. Disconnect the car’s battery for a few minutes to reset the ECM

Recommended tools & DTC Scanners for BMW

Best Diagnostic App for modern BMWs: BimmerLink

Recommended Bluetooth adapter for Bimmerlink: OBDLink CX

Cable adapter for Bimmerlink: Enet Cable USB Type C

For older BMWs we recommend: Autel AutoLink AL319 (2024 version)

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

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