What Does U1112 Mean?
The control module has detected invalid or missing communication data from another primary module on the SCP J1850 network. This is a secondary communication fault that typically accompanies other network codes.
Common Causes
35%
Network bus wiring damage or corrosion in harness connectors
25%
Failed anti-lock brake system (ABS) module network interface
20%
Defective transmission control module (TCM) communication circuit
15%
Poor ground connections at module mounting points
5%
Intermittent short to power or ground on network bus
Diagnostic Steps
1
Step 1: Check for multiple U-codes and identify which modules are reporting communication faults
2
Step 2: Visually inspect SCP network wiring for chafing, pinching, or damage along the entire harness route
3
Step 3: Test continuity of both SCP+ and SCP- circuits between all modules on the network
4
Step 4: Measure voltage on SCP bus lines (should see approximately 2.5-3.5V with key on)
5
Step 5: Perform wiggle test on harness connectors while monitoring network communication with scan tool
Estimated Repair Cost
$150 - $1,400
Parts + labor, varies by vehicle and location
The control module has detected invalid or missing communication data from another primary module on the SCP J1850 network. This is a secondary communication fault that typically accompanies other network codes.
The most common cause of U1112 (SCP (J1850) Invalid or Missing Data for Primary Id) is: Network bus wiring damage or corrosion in harness connectors
Typical repair costs for U1112 range from $150 to $1,400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
May result in loss of anti-lock braking, cruise control, or transmission shift issues depending on affected module. Address promptly to restore full vehicle functionality.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U1112 to identify the root cause.
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Quick Info
Category
Network
System
Network Communication
Difficulty
Type
Manufacturer
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