SCP (J1850) Invalid or Missing Data for Legislated Diagnostics
Your vehicle's communication network between modules is broken or incomplete, like a phone line with static that prevents important messages from getting through. The engine computer can't receive required diagnostic data over the J1850 bus needed to meet emissions testing standards.
The ECM monitors the J1850 SCP (Standard Corporate Protocol) network bus for continuous data transmission from other modules required for OBD-II compliance. If critical messages don't arrive within expected timeframes or contain invalid checksums, the fault is logged. The ECU expects periodic updates on emission-related parameters from transmission, ABS, and body control modules.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| J1850 Bus Message Arrival Rate | Messages received at expected intervals with valid checksums | Missing or corrupted messages for >5 consecutive cycles |
| Data Validity Check | All received diagnostic data within valid ranges | Checksum failures or out-of-range values on SCP network |
Code U1107 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, U1107 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.