What Does U011A Mean?
The PCM has lost communication with the exhaust gas sensor module over the network. This module processes signals from multiple oxygen or NOx sensors in advanced emissions systems.
Common Causes
35%
Faulty exhaust gas sensor control module
30%
Damaged wiring or connectors between PCM and sensor module
20%
CAN bus communication network fault
10%
Poor power supply or ground connection to sensor module
5%
PCM software issue or PCM failure
Diagnostic Steps
1
Step 1: Check battery voltage and inspect ground connections at sensor module location
2
Step 2: Visually inspect exhaust gas sensor module and all associated connectors for damage or corrosion
3
Step 3: Verify power and ground at sensor module connector using wiring diagram
4
Step 4: Check CAN bus voltage signals at module connector (should see activity between 2.0-3.5V on CAN high and low)
5
Step 5: If power, ground, and network signals are present but no communication, replace exhaust gas sensor module
Estimated Repair Cost
$200 - $900
Parts + labor, varies by vehicle and location
The PCM has lost communication with the exhaust gas sensor module over the network. This module processes signals from multiple oxygen or NOx sensors in advanced emissions systems.
The most common cause of U011A (Lost Communication With Exhaust Gas Sensor Module) is: Faulty exhaust gas sensor control module
Typical repair costs for U011A range from $200 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may fail emissions testing and experience reduced fuel economy or performance. Check engine light will illuminate but vehicle is generally safe to drive.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U011A to identify the root cause.
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Quick Info
Category
Network
System
Emissions Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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