BMW DTC P128B – Nox Sensor Signal Regeneration Stop NOx Trap (Bank 1)
DTC P128B meaning on BMW
DTC P128B on a BMW indicates an issue with the NOx sensor signal regeneration stop in the NOx trap for Bank 1. This fault code is related to the nitrogen oxide (NOx) emissions control system in the vehicle.
BMW DTC P128B symptoms
Symptoms of DTC P128B on a BMW may include poor engine performance, reduced fuel efficiency, and the illumination of the check engine light on the dashboard. Additionally, you may notice increased emissions from the vehicle.
BMW DTC P128B causes
The most common causes of DTC P128B on a BMW include a faulty NOx sensor, issues with the NOx trap, wiring or connector problems in the NOx sensor circuit, or a malfunction in the engine control module (ECM).
BMW DTC P128B seriousness
DTC P128B should not be ignored as it can lead to increased emissions and potential damage to the vehicle’s emissions control system. Driving with this fault code present may also result in reduced engine performance and fuel efficiency.
How to diagnose DTC P128B on BMW
To diagnose DTC P128B on a BMW, a diagnostic scan tool can be used to retrieve the fault code and further investigate the NOx sensor signal regeneration stop in the NOx trap for Bank 1. Additionally, a visual inspection of the sensor, trap, wiring, and connectors can help identify any visible issues.
How to fix DTC P128B on BMW
Fixing DTC P128B on a BMW may involve replacing the faulty NOx sensor, repairing any wiring or connector issues, or addressing problems with the NOx trap. It is recommended to follow the manufacturer’s diagnostic and repair procedures to ensure the issue is resolved correctly.
How to erase DTC P128B on BMW
Once the underlying issue causing DTC P128B on a BMW has been fixed, the fault code can be erased using a diagnostic scan tool. By clearing the code, the check engine light should turn off, indicating that the problem has been addressed.
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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