U1105 Chassis Status Request Communication Fault
The U1105 code indicates that a control module (such as the PCM, ABS, or chassis control module) has detected invalid or missing data on the SCP (Standard Corporate Protocol) bus, specifically for a chassis status request. The SCP bus is a Ford communication network operating at 41.6 kbps based on SAE J1850. This code sets when a module requests chassis status information (e.g., suspension, steering, traction control, or wheel speed data) from another module but receives corrupted, incomplete, or no response within the specified timeout. This fault can disrupt critical inter-module coordination.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty chassis control module (e.g., suspension, ABS, or traction control module)
- Open or short circuit in the SCP bus wiring (J1850 communication pins)
- SCP bus terminal resistance out of specification (should be approximately 120 ohms)
- Transmitting module with internal data transmission failure
- Corroded or loose connections in communication bus connectors
- Electromagnetic interference affecting SCP signal integrity
- Faulty primary control module (PCM) that requests the data
3. Symptoms You Will Notice
- Illuminated Check Engine Light or other warning lights
- Erratic behavior of chassis systems (suspension, steering, traction control)
- Loss of communication between modules, possibly causing drivability issues
4. Step-by-Step Diagnosis
Scan for all stored codes and freeze frame data
Inspect SCP bus wiring and connectors for damage, corrosion, or loose connections
Measure resistance across the SCP bus terminals (should be ~120 ohms)
Check for communication signals using an oscilloscope or scan tool
Test individual modules by disconnecting them one at a time to isolate the fault
Repair or replace faulty wiring, connectors, or modules as needed
5. Frequently Asked Questions
Is it safe to drive?▼
The severity is medium. You may be able to drive short distances, but symptoms like erratic chassis behavior or loss of communication could affect safety. It's best to diagnose and repair promptly.
How much does it cost to fix?▼
Costs vary widely: from $50-$150 for a simple wiring repair to $300-$800+ for module replacement, plus diagnostic fees ($100-$200).