P0230 - FUEL PUMP PRIMARY CIRCUIT MALFUNCTION

The fuel pump is activated by a relay that controls the Powertrain Control Module (PCM). The relay function makes it possible for high amperage current to reach the fuel pump without going through the Powertrain Control Module (PCM).

This relay has two sides: a control side and a switch side, which correspond to a coil and a set of electrical contacts respectively. The side with the coil corresponds to the low amperage side. It has a 12-volt power supply when the power switch is passed plus ground. The ground circuit is activated by the PCM controller whenever necessary.

If the fuel pump controller initiates the fuel pump, the PCM initiates the relay coil in the same way, and thus, the coil pulls the electrical contacts closed and thus completes the fuel pump circuit. The fuel pump controller is there to ensure that the voltage flows in the fuel pump activation circuit. Each time the ignition switch is passed, the Powertrain Control Module (PCM) activates the fuel pump circuit for a few seconds, thus activating the fuel pump and safeguarding the system. Again, an RPM signal must be present for the PCM to activate the fuel pump.

The fuel pump controller is always being monitored for faults. When it is turned on, both the controller voltage and the ground circuit voltage must be low, and when the controller is turned off, its voltage and the ground circuit must be high or close to the battery voltage. If the Powertrain Control Module (PCM) does not observe the expected voltage, the DTC code P0230 OBD2 is set.

• The Check Engine service light turns on.
• The fuel pump is not working properly.

If the diagnostic code P0230 has been set, it indicates that one or more of the following problems have occurred

• The fuel pump control circuit may be shorted to ground.
• The fuel pump control circuit may be shorted to the battery voltage.
• Perhaps, one of the wires is rubbing, which can cause a short circuit.
• The relay may be defective.

To solve the P0230 OBDII code, you can do the following:

• You can start by passing the ignition switch without starting the engine, and check to see if the fuel pump turns on and off as you turn the ignition key. If it does as required, by using a scanning tool you can measure the current in the ground control circuit for a few minutes, the result should be less than 1 amp and stay that way. If it does not, you can replace the relay.
• However, the fuel pump does not switch on and off properly, you can remove the relay and watch for loose terminals or worn wires. Change it if you find one of these components in bad condition.
• If all wires and connectors are OK, you can use a test light, which you will connect between the oil pump control circuit power supply and the ground terminals. This light should come on when you pass the ignition switch or when the fuel pump is activated. If it does not, you can check for voltage on one side of the coil. If there is voltage, it indicates a short in the controller's ground circuit. You can repair it.