U1190 SCP Bus Communication Failure
The U1190 code indicates that a control module on the SCP (Standard Corporate Protocol) bus has detected invalid or missing data for a specific Primary ID. This means a critical periodic message on the network is corrupted or absent, disrupting data synchronization between modules such as the PCM, instrument cluster, or ABS module.
1. Commonly Affected Makes
2. Most Common Causes
- Open or shorted SCP bus wiring (SCP+ / SCP- lines shorted to ground, battery, or each other)
- Faulty module that transmits the Primary ID, or that module lacks power or ground
- Damaged or missing SCP bus termination resistors
- Excessive electromagnetic interference (EMI) in the harness
- Low battery voltage or voltage spikes during engine start
- Internal failure in the receiving module (PCM, instrument cluster, ABS, GEM)
3. Symptoms You Will Notice
- Check Engine Light or other warning lights illuminated
- Erratic or inoperative gauges, warning chimes, or ABS functions
4. Step-by-Step Diagnosis
Scan for all stored codes and freeze frame data
Inspect SCP bus wiring for damage, corrosion, or shorts
Check battery voltage and charging system
Test SCP bus termination resistors (typically 120 ohms each)
Isolate the faulty 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 you may experience intermittent gauge or warning light issues. It's best to diagnose and repair promptly to avoid further communication problems.
How much does it cost to fix?▼
Repair costs vary widely: from $50–$200 for wiring repairs, to $200–$800+ for module replacement, plus diagnostic fees.