BMW DTC P123D – NOx Sensor Signal Linear Oxygen Sensor Signal Too Lean (Bank 1)
DTC P123D meaning on BMW
DTC P123D on a BMW indicates that the NOx (Nitrogen Oxide) sensor signal is reporting a linear oxygen sensor signal that is too lean on Bank 1. This means that the engine control module (ECM) has detected a discrepancy in the oxygen levels in the exhaust gas, which can affect the vehicle’s emissions and performance.
BMW DTC P123D symptoms
Symptoms of DTC P123D on a BMW may include:
- Check Engine Light illuminated
- Reduced engine performance
- Increased fuel consumption
- Potential rough idling or misfiring
BMW DTC P123D causes
Common causes of DTC P123D on a BMW include:
- Malfunctioning NOx sensor
- Issues with the oxygen sensor
- Vacuum leaks in the intake system
- Fuel system problems
BMW DTC P123D seriousness
DTC P123D should not be ignored as it can lead to increased emissions, reduced fuel efficiency, and potential engine performance issues. It is important to address this fault to ensure the vehicle operates efficiently and complies with emissions regulations.
How to diagnose DTC P123D on BMW
To diagnose DTC P123D on a BMW, a mechanic may perform the following steps:
- Use a diagnostic scanner to retrieve the fault code
- Inspect the NOx sensor and oxygen sensor for any visible damage
- Check for vacuum leaks in the intake system
- Conduct a fuel system inspection
How to fix DTC P123D on BMW
To fix DTC P123D on a BMW, the following steps may be taken:
- Replace the malfunctioning NOx sensor or oxygen sensor
- Repair any vacuum leaks in the intake system
- Address any fuel system issues
- Clear the fault code and reset the ECM
How to erase DTC P123D on BMW
To erase DTC P123D on a BMW, the fault code can be cleared using a diagnostic scanner. After the necessary repairs have been made to address the underlying issue causing the fault code, the ECM can be reset to clear the code and turn off the Check Engine Light.
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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