SCP (J1850) Invalid or Missing Data for Body Status Request
Your vehicle's body control module isn't receiving or understanding the status messages it's asking for from other modules over the communication network. Think of it like asking someone a question but getting silence or garbled words back instead of a clear answer.
The ECU continuously requests body status data (windows, doors, lights, climate) from the body control module via the J1850 SCP bus. When responses fail to arrive within expected timeframes or contain invalid data checksums, the ECU logs this fault. The system monitors bus voltage levels and message acknowledgment signals.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| SCP Bus Response Time | Message received within 100-200ms | No response or timeout after 500ms+ |
| Data Checksum Validity | Checksum matches calculated value | Checksum mismatch or corrupted frame detected |
Code U1226 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, U1226 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.