SCP (J1850) Invalid or Missing Data for Transmission / Transaxle / PRNDL
Your transmission's data line to the engine computer is broken or sending garbage—like a phone with a bad connection trying to tell someone your gear selection. The ECU can't read what gear you're in or if the transmission is responding properly.
The ECU monitors the SCP (J1850) serial communication bus for valid transmission status messages including PRNDL (Park/Reverse/Neutral/Drive/Low) position data and transmission response signals. When data is missing, corrupted, or arrives outside the expected timing window for a set duration, the fault triggers. The ECU expects regular, valid messages at specific intervals to confirm transmission control module communication.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| SCP Bus Message Reception | Valid transmission data every 10-100ms | Missing or invalid data for >500ms |
| PRNDL Signal Validity | Clear, unambiguous gear position status | Corrupted, conflicting, or no PRNDL data |
Code U1058 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, U1058 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.