What Does U1794 Mean?
The power mirror control module is not acknowledging messages on the network. The system cannot confirm that mirror adjustment commands are being received or executed.
Common Causes
35%
Failed door module or power mirror control module
30%
Damaged wiring or connector in the door, especially at flex point/hinge area
20%
Water intrusion or corrosion in door module or connector
10%
Body control module communication fault with door modules
5%
SCP network issue affecting multiple door or accessory modules
Diagnostic Steps
1
Step 1: Check power and ground to door module/mirror control module at the connector
2
Step 2: Inspect door harness at hinge area for broken or frayed wires (flex repeatedly while monitoring)
3
Step 3: Remove door panel and inspect module connector for water damage, corrosion, or pushed-back pins
4
Step 4: Use scan tool to check if door module appears on network and responds to mirror position commands
5
Step 5: Test SCP bus signal quality at door module connector to verify proper communication voltage levels
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The power mirror control module is not acknowledging messages on the network. The system cannot confirm that mirror adjustment commands are being received or executed.
The most common cause of U1794 (SCP (J1850) Lack of Acknowledgment for Mirrors) is: Failed door module or power mirror control module
Typical repair costs for U1794 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Loss of power mirror adjustment is primarily a convenience issue. Manual mirror positioning is usually still possible. Does not directly affect safe vehicle operation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U1794 to identify the root cause.
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Quick Info
Category
Network
System
Power Mirror / Door Control
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
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