SCP (J1850) Invalid or Missing Data for Experimental #2
Your vehicle's communication network isn't receiving expected data from a module on the J1850 bus—think of it like a radio station not broadcasting on the right frequency. The ECU can't get information it needs to operate properly.
The ECU monitors the J1850 SCP (Standard Corporate Protocol) serial communication bus for valid data packets from other modules. It expects periodic messages with valid checksums and data within normal operating ranges within specific time intervals. If messages are missing, corrupted, or contain invalid checksums for more than a threshold duration, a fault is recorded.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Message Reception Interval | Valid data every 10-100ms | No valid message for >500ms |
| Data Checksum Validity | Checksum matches computed value | Checksum mismatch or missing data |
Code U1094 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, U1094 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.