P0510: Altima reports closed throttle while the valve is open

P0510 in the 2001 Nissan Altima procedure means the closed-throttle switch still reports its closed state while the throttle valve is open. This is a disagreement between operating state and switch information, rather than a general diagnosis of a dirty throttle body.

The switch is separate from the variable position signal

The closed-throttle and wide-open-throttle switches are built into the throttle-position sensor unit. Nissan notes that the wide-open switch serves automatic-transmission control, while the closed switch has a specific backup role in EVAP purge control when the variable throttle sensor malfunctions.

That explains why the switch result can matter to an EVAP investigation. It does not mean every purge fault is caused by the throttle assembly.

Look for the state transition

The manual expects the closed-position circuit to change between the released-pedal and open-throttle conditions. P0510 is associated with a signal remaining at the closed-state voltage when opening should have changed it. The possible causes include a shorted circuit, the switch and the throttle-position sensor.

A stationary function check examines that transition, but Nissan says it may not confirm the first-trip DTC. Its separate confirmation routine also considers throttle-sensor voltage and vehicle movement.

Document both the switch state and the variable throttle signal instead of treating them as one data item. Then follow the circuit and component inspections. Any adjustment or replacement must use the model-specific procedure so that correcting the switch does not create an incorrect throttle baseline.

Documented application

2001 Nissan Altima, EC section. Exact engine, drivetrain and diagnostic applicability must be checked in the cited procedure.

Source

2001 Nissan Altima Factory Service Manual: EC, physical PDF pages 335, 336, 338, 339, 340.