Fuel Pump Monitor Circuit Low Input
The ECU detected the fuel pump control signal is reading too low, meaning the pump isn't getting enough power or the circuit has a bad connection. It's like trying to turn on a light switch but the electrical signal never reaches the bulb.
The ECU monitors the fuel pump relay circuit voltage when the pump should be running. It expects a specific voltage signal (typically 5-12V) to confirm the relay is energized and sending power to the pump. If the voltage drops below the minimum threshold, the ECU logs this fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Fuel Pump Control Voltage | 5-12 volts during pump operation | Below 4.5 volts or open circuit |
| Relay Contact Resistance | Less than 0.5 ohms when closed | Greater than 1.0 ohm or infinite resistance |
Code P1652 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, P1652 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.