Code P0233 indicates that the powertrain control module (PCM) has detected an intermittent electrical issue in the secondary fuel pump circuit. This circuit typically includes the wiring, relay, or control module that delivers power to the fuel pump itself.
The relay or module that controls power to the fuel pump can fail intermittently due to internal wear, pitted contacts, or thermal issues.
Corroded, loose, or chafed wiring and connectors in the fuel pump circuit can cause intermittent electrical contact, especially when the vehicle is in motion.
The internal electrical components of the fuel pump motor can wear out, occasionally causing an open or short circuit as the pump heats up.
If the vehicle is equipped with an inertia safety switch, a malfunctioning switch or its loose connector can momentarily cut power to the fuel pump.
A rare internal failure in the powertrain control module's driver circuit can cause an intermittent loss of the control signal to the relay or pump.
It is not recommended. Because the code indicates an intermittent electrical issue, the vehicle may stall unexpectedly while driving and fail to restart, creating a hazardous situation.
Usually no. Drivers are sometimes told to replace the PCM for this code, but that is generally incorrect. The fault is almost always found in the fuel pump relay, wiring, or the fuel pump itself. The PCM should only be considered after all other components are thoroughly verified.
Yes. If the fuel pump motor is failing internally, it can intermittently draw too much current or create an open circuit, triggering an intermittent secondary circuit code rather than a constant hard fault.
The secondary circuit refers to the portion of the electrical system downstream of the relay or control module. It consists of the power and ground wires that directly operate the fuel pump inside the fuel tank.