The P0C20: Auxiliary Transmission Fluid Pump Phase U-V-W Circuit/Open fault code indicates that there is an open circuit in one of the phases (U, V, or W) of the auxiliary transmission fluid pump. This issue could be caused by faulty wiring, damaged connections, or malfunctioning pump components. An open circuit can lead to improper operation of the transmission fluid pump, potentially affecting transmission cooling and performance.
P0C20 – Quick Overview
| Code | Information |
|---|---|
| Meaning | P0C20: Auxiliary Transmission Fluid Pump Phase U-V-W Circuit/Open |
| Is it serious? | Yes, an open circuit can prevent the pump from operating correctly, leading to transmission issues. |
| Possible causes | – Open circuit in the pump phase U, V, or W – Faulty wiring or connections – Malfunctioning pump components |
| How to diagnose? | – Inspect the phase U, V, and W circuits for open connections – Test the pump components – Check wiring and connections |
P0C20 Meaning
The P0C20 code indicates that there is an open circuit in one of the phases (U, V, or W) responsible for driving the auxiliary transmission fluid pump. The pump ensures proper circulation of transmission fluid, which is essential for cooling and efficient operation of the transmission. An open circuit may result from damaged wiring, poor connections, or failure of internal pump components.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for any additional related codes that may provide further insight into the pump or circuit issues. | OBD-II Scanner |
| Inspect the Phase U, V, and W Circuits for Open Connections | Use a multimeter to check for continuity in the phase U, V, and W circuits. Look for any open circuits or damaged wiring. | Multimeter, Wiring Diagram |
| Check Wiring and Connections | Visually inspect the wiring and connectors for any signs of damage, corrosion, or loose connections that could be causing the open circuit in the pump phase. | Flashlight, Multimeter, Safety Gloves |
| Test Pump Components | Test the auxiliary transmission fluid pump components to ensure that there are no internal failures causing the open circuit. Replace any malfunctioning components as needed. | Diagnostic Tool, Pump Testing Equipment |
| Clear the Code and Test Drive | After repairs, clear the code using an OBD-II scanner and perform a test drive to ensure that the pump is operating correctly and the issue is resolved. | OBD-II Scanner, Vehicle Owner’s Manual |
| Recheck for Codes | After the test drive, re-scan the system to ensure that the P0C20 code does not return. | OBD-II Scanner |
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