Torque Converter Clutch Solenoid Failed On
The torque converter clutch solenoid is stuck in the ON position, preventing proper fluid flow and lock-up control. Think of it like a stuck valve in a water pipe that won't fully open or close.
The ECM monitors solenoid voltage and current draw, expecting specific switching patterns during gear changes and cruise conditions. When the solenoid remains energized continuously or fails to de-energize, the ECU detects abnormal resistance and current flow that exceeds normal parameters.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Solenoid Current Draw | 0.5–1.5 amps with proper cycling | Stuck above 1.5 amps or no response to command |
| Solenoid Coil Resistance | 6–14 ohms | Below 3 ohms (shorted) or above 20 ohms (open) |
Code P1747 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, P1747 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.