U1087 SCP Bus Communication Fault
The control module that stored this DTC has detected missing or invalid data for a specific Primary ID on the SCP (Standard Corporate Protocol) communication network, which is based on the SAE J1850 VPW standard. This indicates a failure in receiving expected periodic messages from another module on the body data bus.
1. Commonly Affected Makes
2. Most Common Causes
- Open circuit, short to ground, or short to battery on the SCP bus (+/-)
- Transmitting module for the Primary ID is failing or disconnected
- Corroded, loose, or damaged terminals in the data bus connectors
- Internal failure of the receiving module (the one storing the code)
- Low battery voltage or excessive electromagnetic interference
3. Symptoms You Will Notice
- Check Engine Light or other warning lights illuminated
- Intermittent or complete loss of function from related modules (e.g., instrument cluster, body control module)
4. Step-by-Step Diagnosis
Check for other related DTCs to identify the affected module
Inspect SCP bus wiring and connectors for damage, corrosion, or loose connections
Measure bus voltage and resistance at the diagnostic connector (DLC) per manufacturer specs
Verify battery voltage is within range and charging system is working properly
If wiring is intact, isolate the transmitting module by disconnecting modules one at a time while monitoring bus activity
5. Frequently Asked Questions
Is it safe to drive?▼
The vehicle may still be drivable, but some body functions (e.g., power windows, door locks, instrument cluster) may not work properly. It is recommended to diagnose and repair the issue soon to avoid further electrical problems.
How much does it cost to fix?▼
Repair costs vary widely depending on the root cause. Simple wiring repairs can cost $100-$200, while replacing a faulty module may range from $300 to $800 or more, including labor.