What Does U1124 Mean?
Another primary identifier data error on the SCP network. The pattern of seven U-codes (U1118-U1124) indicates catastrophic network failure affecting most or all modules on the vehicle communication bus.
Common Causes
50%
Catastrophic network bus failure - short circuit or open circuit in main bus wiring
30%
Total BCM or network gateway failure preventing all network communication
15%
Major electrical event damage (jump start, surge, water damage) affecting multiple modules
5%
Complete loss of network termination resistance or both terminating resistors failed
Diagnostic Steps
1
Step 1: Question owner about recent events (jump start, water intrusion, electrical work, accident) that may explain multiple failures
2
Step 2: Perform comprehensive network test measuring resistance across SCP+ and SCP- with all modules connected and disconnected
3
Step 3: Visually trace main network harness looking for obvious damage, melting, rodent damage, or pinch points
4
Step 4: Disconnect BCM/gateway module and test for short circuits on network bus that may indicate failed module
5
Step 5: If wiring passes all tests, prepare for potential multiple module replacement; verify with known-good module testing if available
Estimated Repair Cost
$250 - $2,500
Parts + labor, varies by vehicle and location
Another primary identifier data error on the SCP network. The pattern of seven U-codes (U1118-U1124) indicates catastrophic network failure affecting most or all modules on the vehicle communication bus.
The most common cause of U1124 (SCP (J1850) Invalid or Missing Data for Primary Id) is: Catastrophic network bus failure - short circuit or open circuit in main bus wiring
Typical repair costs for U1124 range from $250 to $2,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Extensive system failures likely including critical warning systems, gauges, and potentially engine performance. Vehicle may be unsafe or unreliable; tow to facility if multiple systems are non-functional.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U1124 to identify the root cause.
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Quick Info
Category
Network
System
Vehicle Communication Network
Difficulty
Type
Manufacturer
Recommended Tools
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