NOx Sensor Processor Performance Bank 1 Sensor 1
An internal self-test in the control module reports a fault in its processing of the "NOx sensor processing, bank 1 sensor 1" value. The module computes and cross-checks this value redundantly inside its own processor; when the results disagree, the code sets. It points to a hardware or software fault inside the module itself, not to a defect of the external sensor. Causes are an internal processor or memory fault, corrupted control-module software, or low or disturbed module supply voltage.
Affected components
- Ecu internal processing
- Nox sensor b1s1
Common causes
- High likelihood: Internal software anomaly
- Low likelihood: Module software outdated, reflash may resolve
- Low likelihood: Supply voltage outside specification
Possible symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.