Remove the driver's dashboard undercover, then remove the dashboard lower cover.

Disconnect the 13P (or 6P) connector (A) from the parking and back-up sensor switch (B).

Push the switch out from behind the dashboard lower cover.

Check for continuity between the terminals in each switch position according to the table.

If the continuity is not as specified replace the bulbs (C).

Install the parking and back-up sensor switch in the reverse order of removal.