U1199 SCP Network Communication Failure
The U1199 code indicates a communication fault on the SCP (Standard Corporate Protocol) network, which is based on the SAE J1850 PWM standard historically used by Ford. Specifically, it means the main control module has received invalid data or has not received expected data from the external access module (typically the door control module or keyless entry system). This points to an interruption or corruption of data transmission from the door-related module to the vehicle's communication network.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty or failed door control module (DDM/PCM)
- Short, open, or high resistance in the SCP (J1850) bus wiring
- Corroded, bent, or poor connections in the communication bus connectors
- Defective external access module (keyless entry system)
- Lack of voltage supply or ground at the door module
- Severe electromagnetic interference on the communication network
3. Symptoms You Will Notice
- Keyless entry system not working
- Power door locks malfunctioning
- Warning lights on the dashboard related to door or security systems
- Intermittent or no communication with door modules
4. Step-by-Step Diagnosis
Scan for all stored codes and freeze frame data
Inspect the SCP bus wiring and connectors for damage, corrosion, or loose connections
Check voltage and ground at the door control module
Test the door control module and keyless entry module for proper operation
Use an oscilloscope to check the SCP bus signals for integrity
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, the vehicle is generally safe to drive as this is a low-severity code. However, you may experience issues with door locks and keyless entry.
How much does it cost to fix?▼
Repair costs typically range from $100 to $400, depending on whether the issue is a wiring repair or module replacement.