BMW DTC P123C – NOx Sensor Signal Binary Oxygen Sensor Signal Too Lean (Bank 1)
DTC P123C meaning on BMW
DTC P123C on a BMW indicates that the NOx sensor signal binary oxygen sensor signal is too lean in Bank 1. This means that the engine control module (ECM) has detected a lean condition in the exhaust gas, specifically related to the NOx sensor signal.
BMW DTC P123C symptoms
Symptoms of DTC P123C on a BMW may include:
- Check Engine Light (CEL) illuminated
- Reduced engine performance
- Poor fuel efficiency
- Increased emissions
BMW DTC P123C causes
Common causes of DTC P123C on a BMW include:
- Faulty NOx sensor
- Exhaust leaks
- Issues with the oxygen sensor
- Problems with the fuel system
BMW DTC P123C seriousness
DTC P123C should not be ignored as it can lead to increased emissions, reduced engine performance, and potential damage to the catalytic converter. It is important to address this issue promptly to prevent further complications.
How to diagnose DTC P123C on BMW
To diagnose DTC P123C on a BMW, you can:
- Use a diagnostic scanner to retrieve the fault codes
- Inspect the NOx sensor and oxygen sensor for any visible damage
- Check for exhaust leaks
- Perform a fuel system inspection
How to fix DTC P123C on BMW
To fix DTC P123C on a BMW, you may need to:
- Replace the faulty NOx sensor
- Repair any exhaust leaks
- Replace the oxygen sensor if necessary
- Clean or replace fuel system components
How to erase DTC P123C on BMW
To erase DTC P123C on a BMW, you can:
- Use a diagnostic scanner to clear the fault codes
- After fixing the underlying issue, reset the ECM by disconnecting the battery for a few minutes
- Ensure that the repair has been successful by driving the vehicle and checking for any recurring codes
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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