Measures incoming air volume.
If you want, tell me your Nissan model/year and the ECU part number and I’ll fetch a specific pinout for that exact Zexel unit. nissan zexel ecu pinout
Signals the ECU to wake up when the key is turned to the "ON" position. Black/White or Blue 0V (Off) / 12V+ (Key On) Measures incoming air volume
This is a frequent issue on electronic Zexel diesel injection pumps (like the Bosch VP37 licensed variants). Inspect the pins on the ECU. nissan zexel ecu pinout
Check the Tx/Rx pins for continuity to the diagnostic plug. Verify the ECU main power pin reads above 12 Volts when the key is on.
Shared sensor reference ground loop (isolated from dirty chassis ground). Accelerator Pedal Position (APP) Sensor