SCP Communication Failure U1046
The U1046 code indicates a failure in the SCP (Standard Corporate Protocol) communication bus, which is based on SAE J1850 and used primarily by Ford Motor Company. This code sets when a control module (such as the PCM, ABS, or comfort module) detects that data received from another module is corrupted, incomplete, or does not match the expected format for the primary message identifier. The issue can stem from electrical interference, incorrect bus termination, or a faulty transmitting module.
1. Commonly Affected Makes
2. Most Common Causes
- Incorrect or damaged SCP bus termination resistor (should be approximately 120 ohms between pins)
- Short circuit or open circuit in the SCP bus wiring (typically pins 2 and 10 of the DLC connector)
- Loose connections or corrosion in module connectors
- Electromagnetic interference in the data wiring
- Faulty power supply or ground to the transmitting module
- Outdated or corrupted module software
3. Symptoms You Will Notice
- Check Engine Light or other warning lights illuminated
- Erratic behavior of modules (e.g., ABS, transmission, or instrument cluster)
4. Step-by-Step Diagnosis
Scan for all stored codes and freeze frame data
Inspect the SCP bus wiring for shorts, opens, or corrosion, especially at the DLC pins 2 and 10
Measure resistance between pins 2 and 10 at the DLC; should be approximately 60 ohms (two 120-ohm resistors in parallel)
Check for proper power and ground at each module on the SCP network
Perform a network integrity test to isolate the faulty module
5. Frequently Asked Questions
Is it safe to drive?▼
The severity is medium. You can drive short distances, but the vehicle may exhibit drivability issues or loss of certain functions. It's recommended to diagnose and repair promptly.
How much does it cost to fix?▼
Costs vary widely depending on the root cause. A simple wiring repair may cost $100-$200, while replacing a module can range from $300 to $800 or more.