What Does U1230 Mean?
The module is not receiving valid data from the electric defrost system over the SCP (Standard Corporate Protocol) J1850 network bus. This indicates a communication failure between the defrost control module and other vehicle network modules.
Common Causes
35%
Defrost control module failure or internal communication fault
30%
Damaged or corroded wiring in the SCP network circuit to defrost module
20%
Poor ground connection at defrost module or body ground point
15%
Network termination resistor failure or SCP bus short/open circuit
Diagnostic Steps
1
Step 1: Use scan tool to monitor live SCP network traffic and identify which modules are communicating
2
Step 2: Inspect defrost control module connector for corrosion, bent pins, or moisture intrusion
3
Step 3: Test SCP bus voltage at defrost module connector (should see voltage fluctuations during communication)
4
Step 4: Check ground connections at defrost module and body ground points for continuity and resistance
5
Step 5: If all wiring checks pass, substitute or flash/reprogram defrost control module
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
The module is not receiving valid data from the electric defrost system over the SCP (Standard Corporate Protocol) J1850 network bus. This indicates a communication failure between the defrost control module and other vehicle network modules.
The most common cause of U1230 (SCP (J1850) Invalid or Missing Data for Electric Defrost) is: Defrost control module failure or internal communication fault
Typical repair costs for U1230 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
No direct safety impact. Rear window defrost functionality may be compromised, potentially reducing rear visibility in cold/humid conditions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U1230 to identify the root cause.
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Quick Info
Category
Network
System
Body Control/Communication Network
Difficulty
Type
Manufacturer
Recommended Tools
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