SCP (J1850) Invalid or Missing Data for Primary Id
Your vehicle's computer network isn't receiving critical data from a module on the J1850 bus, like a radio losing a station's signal. Without this primary data packet, the system can't communicate properly with other modules.
The ECM monitors the J1850 SCP (Standard Corporate Protocol) serial data bus for valid messages from primary control modules. It verifies that expected data packets arrive within defined timing windows and contain valid checksums. Missing or corrupted frames trigger this fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Message Reception Timeout | Valid data every 10-20ms | No valid data for >100ms window |
| Checksum Validation | Checksum matches calculated value | Checksum mismatch or corrupted payload |
Code U1013 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, U1013 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.