What Does U041B Mean?
The exhaust gas sensor module (typically an NOx sensor module or secondary O2 sensor processor) is transmitting invalid data to the engine control module. This affects emissions monitoring and catalyst efficiency calculations.
Common Causes
32%
Failed exhaust gas sensor module with internal circuit failure or memory corruption
28%
Defective exhaust gas sensor (NOx or wide-band O2) sending out-of-range values
22%
Exhaust gas sensor wiring damage from heat exposure or physical damage
12%
CAN bus communication fault between sensor module and engine control module
6%
Exhaust sensor contamination or degradation providing erratic signals
Diagnostic Steps
1
Step 1: Inspect exhaust gas sensor wiring and connectors for heat damage, melting, or corrosion
2
Step 2: Monitor exhaust gas sensor data PIDs using scan tool during various engine loads and temperatures
3
Step 3: Check sensor heater circuit operation and verify proper resistance and current draw
4
Step 4: Test CAN bus communication between exhaust sensor module and ECM for proper voltage and signal integrity
5
Step 5: Replace exhaust gas sensor if wiring is intact; replace sensor module if new sensor continues to provide invalid data
Estimated Repair Cost
$200 - $1,400
Parts + labor, varies by vehicle and location
The exhaust gas sensor module (typically an NOx sensor module or secondary O2 sensor processor) is transmitting invalid data to the engine control module. This affects emissions monitoring and catalyst efficiency calculations.
The most common cause of U041B (Invalid Data Received From Exhaust Gas Sensor Module) is: Failed exhaust gas sensor module with internal circuit failure or memory corruption
Typical repair costs for U041B range from $200 to $1,400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle will likely enter reduced power mode and fail emissions testing. While not immediately dangerous to drive, continued operation may damage catalytic converter or other emission components. Repair within a few days to prevent additional damage.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U041B to identify the root cause.
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Quick Info
Category
Network
System
Emissions Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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