What does code P1645 mean?

Q: What does code P1645 mean?

Fuel Pump Resistor Switch Circuit. P1645 on Mazda vehicles indicates that the powertrain control module (PCM) has detected an abnormal condition in the fuel pump resistor switch circuit, which controls the voltage supplied to the fuel pump for low-speed and high-speed operation. The PCM monitors the circuit and sets this code when the switch does not respond as expected, often due to an open or shorted circuit or a failed resistor.

DTC codes / Mazda codes / P1645

P1645 · MazdaFuel Pump Resistor Switch Circuit

P1645 on Mazda vehicles indicates that the powertrain control module (PCM) has detected an abnormal condition in the fuel pump resistor switch circuit, which controls the voltage supplied to the fuel pump for low-speed and high-speed operation. The PCM monitors the circuit and sets this code when the switch does not respond as expected, often due to an open or shorted circuit or a failed resistor.

SystemPowertrain

Code typeMazda specific

SeverityMedium

Fix difficultyIntermediate

AreaComputer and output circuits

Guidance is general and written for Mazda vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.