Inspection Procedure

WARNING: This page is about a different car, the 2007 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT FUSE (RADIO NO. 2, AM1, TV)
1. Remove the RADIO NO. 2 and TV fuses from the passenger side junction block.
2. Remove the AM1 fuse from the driver side junction block.
3. Measure the resistance of the fuses.
  Standard resistance:
  
  Below 1 Ω
  
  NG: REPLACE FUSE
  
  OK: Go to next step

INSPECT RELAY (Marking: ACC)

Remove the ACC relay from the passenger side junction block.

Measure the resistance of the relay.

Fig 1: Measuring Resistance Between Relay Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Specified Condition
3 - 5	Below 1 Ω
3 - 5	10 kΩ or higher (when battery voltage is applied to terminals 1 and 2)

NG: REPLACE RELAY

OK: Go to next step

CHECK WIRE HARNESS (NAVIGATION ECU - BATTERY AND BODY GROUND)

Disconnect the N3 and N7 ECU connectors.

Fig 2: Identifying N3 And N7 ECU Connectors Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Measure the resistance and voltage of the wire harness side connectors.

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Specified Condition
N3-17 (GND1) - Body ground	Below 1 Ω
N7-7 (SNSE) - Body ground	Below 1 Ω

Standard voltage

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
N3-18 (ACC) - Body ground	Ignition switch ACC	10 to 14 V
N3-9 (+B) - Body ground	Always	10 to 14 V

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR

OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE OR DIAGNOSTIC TROUBLE CODE CHART