P0090 indicates that the engine computer has detected an open circuit in the electrical path controlling the fuel pressure regulator. This means there is a break in the wiring, a disconnected plug, or a failed internal solenoid preventing the regulator from operating. As a result, the engine cannot properly manage fuel pressure, which often leads to driveability issues or a no-start condition.
An open, broken, or corroded wire or connector in the regulator control circuit is the most common cause of this code.
The internal solenoid of the fuel pressure regulator can fail electrically, creating an open circuit within the component itself.
Corroded, pushed back, or loose terminals in the regulator or engine computer connectors can cause an open circuit condition.
A blown power supply fuse or failed relay for the fuel system can cause an open circuit condition on the control side.
An internal failure in the engine computer driver circuit is extremely rare and should only be considered after all wiring and components are verified.
An open circuit means there is a break somewhere in the electrical path, like a disconnected wire, a broken wire, or a failed internal component, preventing electricity from flowing to the fuel pressure regulator.
It is generally not recommended. The engine may stall unexpectedly or fail to start, which could leave you stranded or create a hazardous situation in traffic.
No, replacing the PCM is almost never the fix for P0090. The vast majority of the time, the cause is damaged wiring, a bad connector, or a failed fuel pressure regulator solenoid. The PCM is the last component to suspect.