Pinpoint Test I : Line Pressure Control (LPC) Solenoid: Notes
WARNING: This page is about a different car, the 2018 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.
Line Pressure Control (LPC) Solenoid
Refer to Transmission Controls - 6F50/6F55 for schematic and connector information.
Normal Operation
The PCM controls the hydraulic line pressure by varying the amount of current applied to the LPC solenoid. When no current is applied to the LPC solenoid, the solenoid, is fully opened, resulting in the maximum amount of hydraulic pressure to the main pressure regulator valve. When maximum current is applied, the LPC solenoid is fully closed, resulting in minimum pressure to the main pressure regulator valve.
NOTE:
Without a voltage signal return to the PCM, the transmission solenoid power control relay is commanded OFF. Using a fused jumper wire between a transmission solenoid control circuit and the signal return circuit, the transmission solenoid power control relay circuit supplies power to the transmission solenoids when the ignition is cycled from off to on. Do not use a solenoid control circuit that may be at fault, refer to DTC Chart: PCM for a fault listing.
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| P0748 | LPC Solenoid Electrical | LPC solenoid electrical circuit general fault. May set along with DTC P0960, P0962 and P0963. |
| P0960 | LPC Solenoid Control Circuit/Open | Open circuit in solenoid or solenoid circuitry. |
| P0961 | LPC Solenoid Control Circuit Range/Performance | Intermittent short to ground in solenoid or solenoid circuitry. |
| P0962 | LPC Solenoid Control Circuit Low | Short to ground in solenoid or solenoid circuitry. |
| P0963 | LPC Solenoid Control Circuit High | Short to power in solenoid circuitry. |
Possible Sources
- Connectors damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals
- LPC solenoid
- Transmission internal wiring harness frame
- PCM