Code P128F possible causes
- Faulty fuel rail pressure sensor
- Fuel rail pressure sensor harness is open or shorted
- Poor electrical connection in fuel rail pressure sensor circuit
How is code P128F repaired?
Start by checking the “Possible Causes” listed above. Visually inspect the wiring harness and associated connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
What are the possible symptoms of code P128F?
- Check Engine Light on (or Service Engine Soon warning light)
What does code P128F mean?
The fuel supply rail pressure sensor transmits fuel pressure and temperature information via serial data. The internal microprocessor of the fuel supply rail pressure sensor enables 4 separate sensor outputs from a 3-wire sensor. The Engine Control Module (ECM) supplies the fuel supply rail pressure sensor with a 5V reference circuit, a low reference circuit, and an asynchronous/serial data signal circuit. The asynchronous signal means communication only goes from the fuel supply rail pressure sensor to the ECM. The ECM decodes the serial data signal into separate voltages that are displayed on a scan tool as fuel temperature sensor, fuel rail pressure sensor, and fuel rail pressure sensor 2 voltage inputs.