OBD-II Trouble Code Description for P0230 Subaru

Fuel Pump Primary Circuit

What does this mean?

OBD2 Code P0230 Subaru definition:
The fuel pump is activated by a PCM-controlled relay. 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). For obvious reasons it’s better to not have higher amperage current anywhere near the PCM. Higher amperage current creates more heat but also in the event of a failure, can cause a PCM failure. This principal applies to any relay. The higher amperages are kept under the hood, away from sensitive areas The relay contains basically two sides. The “control” side which is basically a coil and the “switch” side which is a set of electrical contacts. The control side (or coil side) is the low amp side. It’s fed a switched ignition feed (12 volts with key on)and a ground. The ground circuit is activated by the PCM driver when appropriate. 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. This closed switch allows voltage to flow on the fuel pump activation circuit, activating the pump. 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. The fuel pump won’t be activated again until the PCM sees an RPM signal. The driver in the PCM is monitored for faults. When activated the driver or ground circuit voltage should be low. When deactivated the driver/ground potential voltage should be high or near battery voltage. If the PCM sees a voltage other than what is expected, P0230 Subaru may be set.

Symptoms

Possible sumptoms of OBD code P0230 Subaru
Symptoms of a P0230 Subaru DTC may include: MIL (malfunction indicator lamp) illumination No start condition No fuel pump operation Fuel pump runs all the time with ignition on

Causes

Possible causes of OBD code P0230 Subaru
Potential causes of a P0230 Subaru code include: Short to ground on control circuit Fuel pump control circuit open Short to battery voltage on control circuit Harness chafing causing one of above conditions Bad relay Bad PCM

Possible Solutions

Command the fuel pump on and off by using a scan tool or simply turning the ignition key on and off without starting the engine. 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. It should be less than an amp and stay less than an amp. If it doesn’t then replacing the relay is a good idea at this point. If the fuel pump won’t activate and deactivate, then remove the relay and visually check for discoloration due to heat or loose terminals. If okay, install a test light between the control circuit ignition feed and ground driver terminals (If you’re not sure, don’t attempt). The test light should illuminate when the key is on or the fuel pump is commanded on. If it doesn’t, then make sure there is voltage on one side of the coil (switched ignition feed). If voltage is present repair the open or short on the control ground circuit.