What Does U2021 Mean?
A module on the vehicle network is receiving invalid or corrupted data from another module. This indicates data transmission errors, possibly due to network interference, faulty module, or wiring issues.
Common Causes
30%
Network bus wiring damage or poor connections
25%
Failed or failing control module transmitting corrupt data
20%
Electromagnetic interference affecting network signals
15%
Low voltage or power supply issues causing data corruption
10%
Incorrect network termination or missing terminating resistor
Diagnostic Steps
1
Step 1: Use advanced scan tool to identify which modules are reporting the fault and which module is sending invalid data
2
Step 2: Inspect network bus wiring between affected modules for damage, pinching, or improper repairs
3
Step 3: Check battery voltage and charging system to ensure stable voltage during network communication
4
Step 4: Measure network bus resistance and verify proper termination (typically 60 ohms for CAN bus, 120 ohms for J1850)
5
Step 5: Isolate suspected faulty module by disconnecting it and checking if fault clears, replace module if confirmed
Estimated Repair Cost
$150 - $1,000
Parts + labor, varies by vehicle and location
A module on the vehicle network is receiving invalid or corrupted data from another module. This indicates data transmission errors, possibly due to network interference, faulty module, or wiring issues.
The most common cause of U2021 (Invalid /fault data received (Non SCP)) is: Network bus wiring damage or poor connections
Typical repair costs for U2021 range from $150 to $1,000, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Depending on which systems are affected, this could impact safety-critical functions like ABS, airbags, or stability control. Multiple warning lights may illuminate and various vehicle functions may become inoperative.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U2021 to identify the root cause.
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Quick Info
Category
Network
System
Vehicle Communication Network
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
