U1131 SCP Bus Fuel Data Fault
The U1131 code indicates a failure in the SCP (Standard Corporate Protocol) communication bus, which is based on the J1850 protocol used by Ford and its associated brands. Specifically, the receiving module (typically the PCM) is not receiving valid fuel system data from the transmitting module over the SCP data bus. This can be caused by wiring issues, a faulty module, or incorrect bus termination.
1. Commonly Affected Makes
2. Most Common Causes
- Open or short circuit in the SCP bus wiring (SCP+ and SCP- circuits)
- Incorrect or damaged bus termination resistor
- Corroded connectors in the data bus
- External electrical interference on the communication bus
3. Symptoms You Will Notice
- Check Engine Light illuminated
- Fuel system performance issues, such as hard starting or stalling
4. Step-by-Step Diagnosis
Scan for other related codes and check freeze frame data
Inspect SCP bus wiring for damage, shorts, or opens
Test bus termination resistance (should be around 120 ohms)
Check for corrosion at bus connectors
Verify operation of the Fuel Pump Driver Module (FPDM)
If all else fails, test or replace the PCM
5. Frequently Asked Questions
Is it safe to drive?▼
The vehicle may still be drivable, but performance issues like stalling or poor fuel delivery can occur. It's recommended to diagnose and repair promptly to avoid being stranded.
How much does it cost to fix?▼
Costs vary widely depending on the cause. Wiring repairs may be $100-$300, while replacing a PCM or FPDM can range from $400-$1000 including labor.