SCP (J1850) Invalid or Missing Data for Function Read Engine Torque
Your vehicle's onboard computer can't receive engine torque data from the transmission control module over the communication network. It's like two walkie-talkies trying to talk but one isn't transmitting clearly.
The ECM monitors incoming SCP (J1850) bus messages from the TCM containing calculated engine torque values needed for transmission shift logic and torque management. When valid torque data fails to arrive within expected timing windows or contains invalid values, the ECU triggers this code as a communication fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| SCP Message Reception Rate | Continuous valid messages every 10-100ms | Missing or invalid data for 2+ consecutive cycles |
| Engine Torque Data Range | 0-500 Nm depending on engine | Out-of-range or corrupted values detected |
Code U1308 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, U1308 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.