What Does U1241 Mean?
Duplicate of U1240, indicating another module or the same module is experiencing Primary ID data loss. Multiple instances suggest either a critical network failure or complete loss of the module that broadcasts Primary ID information.
Common Causes
40%
Complete failure of BCM or PCM preventing ID broadcast to multiple modules
25%
Severe SCP bus wiring damage affecting all network communication
15%
Multiple modules experiencing power loss simultaneously
12%
Network short circuit causing bus voltage collapse
8%
Failed bus terminating resistor causing signal reflection
Diagnostic Steps
1
Step 1: Determine if U1240 and U1241 are set by same module or different modules using scan tool
2
Step 2: Check battery voltage and main power distribution to all network modules
3
Step 3: Measure SCP bus voltage with oscilloscope - should see 0-7V square wave signals
4
Step 4: Disconnect modules one at a time to isolate potential short circuit causing bus failure
5
Step 5: Replace identified faulty module or repair wiring after isolation testing
Estimated Repair Cost
$250 - $1,200
Parts + labor, varies by vehicle and location
Duplicate of U1240, indicating another module or the same module is experiencing Primary ID data loss. Multiple instances suggest either a critical network failure or complete loss of the module that broadcasts Primary ID information.
The most common cause of U1241 (SCP (J1850) Invalid or Missing Data for Primary Id) is: Complete failure of BCM or PCM preventing ID broadcast to multiple modules
Typical repair costs for U1241 range from $250 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Moderate to significant concern. Multiple Primary ID failures can affect starting, security systems, and coordination between critical vehicle systems.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U1241 to identify the root cause.
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Quick Info
Category
Network
System
Body Control / Network Communication
Difficulty
Type
Manufacturer
Recommended Tools
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