Fuel Pump Resistor Switch Circuit Malfunction
The fuel pump has a resistor circuit that controls its speed, and the ECU detects a problem with this electrical switch. Think of it like a dimmer switch for a light—if the dimmer doesn't respond properly, the light won't adjust as intended.
The ECU monitors the fuel pump resistor circuit voltage and current draw to ensure the pump speed control is functioning. It detects open circuits, shorts, or resistance values outside normal range. The ECU expects specific voltage transitions when switching between low and high pump speeds.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Resistor Circuit Voltage | 5-12V with proper switching transitions | No voltage change or out-of-range readings |
| Circuit Current Draw | 0.5-2.0A during operation | Open circuit (0A) or short circuit (>2.5A) |
Code P1654 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, P1654 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.