Pressure Control Solenoid C Intermittent
The transmission's pressure control solenoid C is cutting in and out intermittently, like a faulty light switch that flickers on and off. This causes the transmission to struggle with pressure regulation, affecting shift quality and performance.
The ECU monitors current draw and response time from solenoid C to verify it engages and releases properly. It detects intermittent electrical or hydraulic faults by comparing expected solenoid performance against actual feedback signals and pressure readings.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Solenoid Current Draw | 0.5–2.0 amps during operation | Erratic or missing current pulses below 0.3 amps or dropouts |
| Response Time | 10–50 milliseconds activation | Delayed response or no activation detected |
Code P0799 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, P0799 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.