What Does U1077 Mean?
This code indicates a different module on the SCP network is not communicating properly or transmitting invalid data. Similar to U1076 but references a different Primary ID on the network.
Common Causes
35%
Failed control module not responding on network
30%
Corroded or damaged network wiring between modules
20%
Poor power or ground supply to specific module
10%
Electrical noise or interference on network bus
5%
Water intrusion in module or connector causing shorts
Diagnostic Steps
1
Step 1: Verify battery and charging system voltage to ensure stable power supply
2
Step 2: Use scan tool to identify specific module ID that is not responding
3
Step 3: Inspect power and ground circuits to the affected module using wiring diagrams
4
Step 4: Check for water damage or corrosion in module connectors and housing
5
Step 5: Test SCP bus voltage levels (should see 0V and 5V switching with scope)
Estimated Repair Cost
$150 - $900
Parts + labor, varies by vehicle and location
This code indicates a different module on the SCP network is not communicating properly or transmitting invalid data. Similar to U1076 but references a different Primary ID on the network.
The most common cause of U1077 (SCP (J1850) Invalid or Missing Data for Primary Id) is: Failed control module not responding on network
Typical repair costs for U1077 range from $150 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Depending on the affected module, could impact safety systems like ABS, traction control, or airbag systems. May also cause driveability issues or no-start conditions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U1077 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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