Inspection Procedure

WARNING: This page is about a different car, the 2007 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.

CHECK BACK-UP LIGHT
1. Move the shift lever to the R position and check if the back-up lights turn on.
  OK: The back-up lights turn on.
NG: GO TO LIGHTING SYSTEM

OK: Go to Next Step

CHECK WIRE HARNESS (BK/UP LP RELAY - NAVIGATION ECU AND BODY GROUND)

Disconnect the N3 ECU connector.
Disconnect the 3H engine room relay block connector.

Measure the resistance of the wire harness side connectors.

Standard resistance

STANDARD RESISTANCE REFERENCE CHART

Tester Connection	Specified Condition
N3-20 (REV) - 3H-8	Below 1 Ω
N3-20 (REV) - Body ground	10 kΩ or higher

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 1: Checking Wire Harness (BK/UP LP Relay - Navigation ECU And Body Ground)

OK: REPLACE NAVIGATION ECU