Pressure Control Solenoid Malfunction
The transmission's pressure control solenoid isn't working properly, causing the transmission fluid pressure to be incorrect. Think of it like a water valve that's stuck or broken—it can't properly regulate the flow and pressure needed for smooth gear shifts.
The ECM monitors solenoid current draw and transmission line pressure feedback through pressure sensors. It expects a specific current range and corresponding pressure rise when the solenoid is commanded on. If actual pressure doesn't match expected values within a threshold window, the fault is triggered.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Solenoid Current Draw | 0.5–1.5 amps when commanded | Out of range or no response |
| Transmission Line Pressure | 40–120 PSI (varies by gear/load) | Below 20 PSI or erratic response |
Code P0746 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, P0746 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.