What Does U1091 Mean?
Similar to U1090, this code indicates missing or invalid data on the J1850 SCP communication network for non-legislated diagnostics. The specific data message or parameter ID differs from U1090 but represents another communication failure on the same bus.
Common Causes
35%
Damaged or corroded wiring harness between communicating modules
30%
Faulty control module failing to transmit required messages
20%
Poor electrical connections at module connector terminals
10%
Bus termination resistor failure or missing
5%
Electrical interference from damaged components or aftermarket devices
Diagnostic Steps
1
Step 1: Cross-reference U1091 with manufacturer-specific documentation to identify the specific data parameter and source module
2
Step 2: Monitor SCP bus communication using appropriate scan tool to verify which messages are missing
3
Step 3: Perform continuity and resistance tests on SCP+ and SCP- circuits throughout the network
4
Step 4: Check for voltage drops or intermittent connections by wiggle-testing harnesses while monitoring bus activity
5
Step 5: Isolate modules one at a time to identify if a faulty module is pulling down or disrupting the bus
Estimated Repair Cost
$150 - $900
Parts + labor, varies by vehicle and location
Similar to U1090, this code indicates missing or invalid data on the J1850 SCP communication network for non-legislated diagnostics. The specific data message or parameter ID differs from U1090 but represents another communication failure on the same bus.
The most common cause of U1091 (SCP (J1850) Invalid or Missing Data for Non-Legislated Diagnostics) is: Damaged or corroded wiring harness between communicating modules
Typical repair costs for U1091 range from $150 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Generally safe to drive but vehicle features may be inoperative or work intermittently. Diagnostic capability may be limited during service.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U1091 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Network
System
Communication Network
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
