What Does U1055 Mean?
The control module is not receiving valid identification data from another module on the SCP (Standard Corporate Protocol) J1850 communication network. This indicates a breakdown in communication between modules that prevents proper system identification.
Common Causes
35%
Faulty or corroded network connector/terminal at the affected module
30%
Defective control module failing to broadcast its identification data
20%
Damaged or shorted SCP network bus wiring between modules
10%
Low vehicle battery voltage affecting module communication
5%
Incorrect module programming or software corruption
Diagnostic Steps
1
Step 1: Check battery voltage - must be above 12.0V with key on, ensure good battery connections
2
Step 2: Inspect all network connectors and terminals for corrosion, damage, or looseness
3
Step 3: Use scan tool to monitor network communication and identify which module is not responding with ID data
4
Step 4: Check SCP bus voltage at network terminals (should be 0-7V pulsing) using oscilloscope or multimeter
5
Step 5: Test resistance of SCP network wiring between modules (should be approximately 50-120 ohms)
6
Step 6: If specific module identified, swap with known-good module to confirm failure
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
The control module is not receiving valid identification data from another module on the SCP (Standard Corporate Protocol) J1850 communication network. This indicates a breakdown in communication between modules that prevents proper system identification.
The most common cause of U1055 (SCP (J1850) Invalid or Missing Data for Primary Id) is: Faulty or corroded network connector/terminal at the affected module
Typical repair costs for U1055 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may experience drivability issues, warning lights, or loss of certain functions. Generally safe to drive but should be diagnosed promptly to prevent secondary issues.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U1055 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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