BMW DTC P1242 – Secondary Upstream Manifold Air Pressure Sensor Signal Too High in Deceleration
DTC P1242 meaning on BMW
The Diagnostic Trouble Code (DTC) P1242 on a BMW indicates that the Secondary Upstream Manifold Air Pressure Sensor is detecting a signal that is too high during deceleration. This sensor is responsible for monitoring the pressure in the intake manifold and providing feedback to the engine control module.
BMW DTC P1242 symptoms
Symptoms of DTC P1242 on a BMW may include:
- Check Engine Light illuminated
- Decreased engine performance
- Engine stalling or hesitation during deceleration
- Increased fuel consumption
BMW DTC P1242 causes
The possible causes of DTC P1242 on a BMW include:
- Faulty Secondary Upstream Manifold Air Pressure Sensor
- Vacuum leaks in the intake system
- Issues with the intake manifold
- Wiring or connector problems in the sensor circuit
BMW DTC P1242 seriousness
While DTC P1242 may not cause immediate harm to the vehicle, it can lead to decreased engine performance and potentially affect fuel efficiency. Ignoring this issue can result in further damage to engine components over time.
How to diagnose DTC P1242 on BMW
To diagnose DTC P1242 on a BMW, you can follow these steps:
- Use a diagnostic scanner to retrieve the fault code and freeze frame data
- Inspect the Secondary Upstream Manifold Air Pressure Sensor for any visible damage
- Check for vacuum leaks in the intake system
- Test the sensor’s voltage and resistance values according to manufacturer specifications
How to fix DTC P1242 on BMW
To fix DTC P1242 on a BMW, you can try the following solutions:
- Replace the faulty Secondary Upstream Manifold Air Pressure Sensor
- Repair any vacuum leaks in the intake system
- Inspect and repair any wiring or connector issues in the sensor circuit
- Clear the fault code and test drive the vehicle to ensure the issue is resolved
How to erase DTC P1242 on BMW
To erase DTC P1242 on a BMW, you can use a diagnostic scanner to clear the fault code from the engine control module’s memory. After clearing the code, it is recommended to test drive the vehicle to ensure that the issue has been successfully resolved.
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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