NOx Sensor A Communication Error
The U059E code indicates a communication fault between the engine control module (ECM) and the Nitrogen Oxide (NOx) Sensor 'A'. The ECM detects that data from the sensor is invalid, corrupted, or not within expected parameters as defined by SAE J2012. This typically points to a problem in the CAN bus communication circuit rather than a direct measurement error by the sensor. Possible causes include electrical issues in the CAN bus wiring, internal sensor circuit failure, or loss of power/ground to the sensor.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Internal communication circuit failure in NOx Sensor 'A'
- CAN bus wiring shorted, open, or high resistance
- Corroded, damaged, or bent pins in sensor harness connectors
- Loss of voltage supply or ground to the NOx sensor
- Electromagnetic interference corrupting data signal
- Internal ECM/PCM failure processing the signal
3. Symptoms You Will Notice
- Check Engine Light illuminated
- Possible increased emissions or failed emissions test
4. Step-by-Step Diagnosis
Scan for additional related codes (e.g., U059E, U0100).
Inspect NOx sensor connector and wiring for damage, corrosion, or bent pins.
Check voltage supply and ground at the sensor connector (typically 12V and good ground).
Test CAN bus wiring for continuity, shorts, and resistance (60 ohms typical).
If wiring and power are OK, suspect faulty NOx sensor or ECM.
5. Frequently Asked Questions
Is it safe to drive?▼
Driving is possible but not recommended for extended periods. The vehicle may fail emissions and could enter limp mode, reducing performance. Have it diagnosed promptly.
How much does it cost to fix?▼
Repair costs range from $150 to $600 depending on the cause. A new NOx sensor costs $100–$300 plus labor; wiring repairs are typically $100–$200.