If the fuel pump activates and deactivates, then start the vehicle and measure the current on the control (ground) circuit for a couple of minutes. Harness chafing causing one of above conditionsĬommand the fuel pump on and off by using a scan tool or simply turning the ignition key on and off without starting the engine.Short to battery voltage on control circuit.Potential causes of a P0230 code include: Fuel pump runs all the time with ignition on.MIL (malfunction indicator lamp) illumination.If the PCM sees a voltage other than what is expected, P0230 may be set. When deactivated the driver/ground potential voltage should be high or near battery voltage. When activated the driver or ground circuit voltage should be low. The driver in the PCM is monitored for faults.

The fuel pump won't be activated again until the PCM sees an RPM signal.

Whenever the key is turned on, the PCM grounds the fuel pump circuit for a few seconds, activating the fuel pump and pressurizing the system. This closed switch allows voltage to flow on the fuel pump activation circuit, activating the pump. When the PCM fuel pump driver activates the relay coil, the coil acts as an electromagnet that pulls the electrical contacts closed which completes the fuel pump circuit. The ground circuit is activated by the PCM driver when appropriate. It's fed a switched ignition feed (12 volts with key on)and a ground. The control side (or coil side) is the low amp side. The 'control' side which is basically a coil and the 'switch' side which is a set of electrical contacts. The higher amperages are kept under the hood, away from sensitive areas Higher amperage current creates more heat but also in the event of a failure, can cause a PCM failure. Just as the name implies, a 'relay' permits the transmittal of higher amperage current to the fuel pump without that current having to travel through the PCM (Powertrain Control Module).įor obvious reasons it's better to not have higher amperage current anywhere near the PCM. The fuel pump is activated by a PCM-controlled relay. Although generic, the specific repair steps may vary depending on make/model. This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles. Fuel Pump Primary (Control) Circuit Malfunction What does that mean?

2005 expedition fuel pump