What Does U1203 Mean?
Similar to U1202, this code indicates invalid or missing data from window control modules on the SCP network. Multiple U-codes often indicate a network-wide communication issue rather than isolated module failure.
Common Causes
35%
SCP network bus failure or short to ground/power
25%
Multiple module failures affecting network integrity
25%
Corroded or damaged network connectors at central junction box
15%
Aftermarket accessory interfering with network communication
Diagnostic Steps
1
Step 1: Verify if code is present in multiple modules using scan tool global scan function
2
Step 2: Disconnect aftermarket accessories one at a time and retest network communication
3
Step 3: Measure resistance across SCP bus terminals; should read approximately 120 ohms
4
Step 4: Perform voltage drop test on network wiring between modules
5
Step 5: Isolate affected circuit by disconnecting modules sequentially to identify short or interference source
Estimated Repair Cost
$100 - $650
Parts + labor, varies by vehicle and location
Similar to U1202, this code indicates invalid or missing data from window control modules on the SCP network. Multiple U-codes often indicate a network-wide communication issue rather than isolated module failure.
The most common cause of U1203 (SCP (J1850) Invalid or Missing Data for Windows) is: SCP network bus failure or short to ground/power
Typical repair costs for U1203 range from $100 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
No immediate safety concerns. Vehicle is safe to operate but may have limited window functionality.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U1203 to identify the root cause.
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Quick Info
Category
Network
System
Body Control Network
Difficulty
Type
Manufacturer
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