U1110 SCP Bus Invalid Data
The U1110 code indicates that a control module on the SCP (Standard Corporate Protocol) network has detected invalid or missing data for a specific Primary ID. This means a critical periodic message either didn't arrive or was corrupted, preventing proper data synchronization between modules such as the PCM, instrument cluster, body control module (GEM/BCM), or HVAC module.
1. Commonly Affected Makes
2. Most Common Causes
- Open or shorted SCP bus wiring (SCP+ or SCP- lines) to ground, battery, or each other
- Faulty module that transmits the Primary ID (e.g., PCM, instrument cluster, GEM) or loss of power/ground to that module
- Damaged or missing SCP bus termination resistors (typically located in the instrument cluster and PCM or GEM)
- Excessive electromagnetic interference (EMI) on the communication harness
- Internal failure of the receiving module that stores the DTC
3. Symptoms You Will Notice
- Check Engine Light or other warning lights illuminated
- Erratic or inoperative gauges (speedometer, fuel level, etc.)
- Intermittent or complete loss of communication with certain modules
- Harsh or improper transmission shifting
- HVAC system not working correctly
4. Step-by-Step Diagnosis
Scan all modules for related DTCs and note which modules are not communicating
Visually inspect the SCP bus wiring for damage, corrosion, or shorts
Measure resistance between SCP+ and SCP- at the DLC (should be approximately 60 ohms with two termination resistors)
Check for proper power and ground at the module that transmits the missing Primary ID
Use a scope or breakout box to monitor SCP bus activity for noise or missing messages
5. Frequently Asked Questions
Is it safe to drive?▼
The vehicle may still be drivable, but you may experience erratic gauge readings, transmission issues, or other drivability concerns. It's best to diagnose and repair the issue promptly to avoid further problems.
How much does it cost to fix?▼
Repair costs vary widely depending on the root cause. Simple wiring repairs can cost $100-$300, while replacing a faulty module (e.g., PCM or instrument cluster) can range from $400 to $1,200 or more, including labor.