What Does U1101 Mean?
Another instance of a module not receiving primary identification data from a network module. This indicates a specific module-to-module communication failure on the J1850 bus.
Common Causes
35%
Failed or failing control module unable to transmit identification data
28%
Network bus circuit open or short to ground
22%
Module power supply or ground circuit failure
12%
Connector corrosion or terminal damage at affected module
3%
Software corruption or module programming issue
Diagnostic Steps
1
Step 1: Use scan tool to poll all modules and identify which specific module is not responding
2
Step 2: Check for blown fuses or tripped circuit breakers supplying power to the non-responsive module
3
Step 3: Measure voltage at the affected module connector; verify battery voltage on power pins and good ground
4
Step 4: Inspect network bus circuits at the DLC and affected module for proper resistance and continuity
5
Step 5: Attempt to reprogram or reflash the affected module if all circuits test good
Estimated Repair Cost
$150 - $1,400
Parts + labor, varies by vehicle and location
Another instance of a module not receiving primary identification data from a network module. This indicates a specific module-to-module communication failure on the J1850 bus.
The most common cause of U1101 (SCP (J1850) Invalid or Missing Data for Primary Id) is: Failed or failing control module unable to transmit identification data
Typical repair costs for U1101 range from $150 to $1,400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
System functionality depends on which module has lost communication. May affect safety systems like ABS or airbags, or comfort features like climate control.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U1101 to identify the root cause.
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Quick Info
Category
Network
System
Vehicle Communication Network
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
