What Does U059E Mean?
The engine control module or emissions system is receiving invalid data from NOX sensor A, which monitors nitrogen oxide levels in the exhaust stream. This is typically part of the selective catalytic reduction (SCR) or lean NOX trap system.
Common Causes
35%
Failed NOX sensor A with internal element contamination or sensor circuit failure
30%
Damaged wiring harness or corroded connector pins between NOX sensor A and control module
20%
Contamination of NOX sensor from oil consumption, coolant leaks, or incorrect diesel exhaust fluid
10%
Software issue or calibration error in engine control module affecting sensor data interpretation
5%
Exhaust leak near NOX sensor location causing incorrect ambient air readings
Diagnostic Steps
1
Step 1: Monitor live data for NOX sensor A readings; compare values to expected ranges for current engine operating conditions and exhaust temperature
2
Step 2: Inspect NOX sensor connector and wiring for damage, corrosion, or loose connections; check sensor heater circuit operation with multimeter
3
Step 3: Check exhaust system for leaks near sensor location and inspect sensor for physical damage or excessive carbon buildup
4
Step 4: Verify proper DEF system operation if equipped; test DEF quality and concentration; check for oil consumption or coolant contamination
5
Step 5: If sensor wiring and exhaust system are intact, replace NOX sensor A and perform sensor relearn procedure per manufacturer specifications
Estimated Repair Cost
$300 - $1,200
Parts + labor, varies by vehicle and location
The engine control module or emissions system is receiving invalid data from NOX sensor A, which monitors nitrogen oxide levels in the exhaust stream. This is typically part of the selective catalytic reduction (SCR) or lean NOX trap system.
The most common cause of U059E (Invalid Data Received From NOX Sensor "A") is: Failed NOX sensor A with internal element contamination or sensor circuit failure
Typical repair costs for U059E range from $300 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle will likely experience reduced power and may not pass emissions testing. May trigger emissions-related limp mode. No immediate safety concern but continued operation may damage catalytic converter or SCR system.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U059E to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Network
System
Emissions Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
