Inspection Procedure

WARNING: This page is about a different car, the 2004 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.

PERFORM ACTIVE TEST BY HAND-HELD TESTER
1. Connect the hand-held tester to the DLC3.
2. Check the front fog using ACTIVE LIST.
Front Controller:

Fig 1: Front Controller Values Table Using Lexus Hand-Held Tester
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON (See PROBLEM SYMPTOMS TABLE )
2. NG: Go to next step.
INSPECT FOG LAMP RELAY
1. Inspect fog lamp relay continuity
  
  Fig 2: Fog Lamp Relay Continuity Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
OK:

Fig 3: Identifying Fog Lamp Relay Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: REPLACE FOG LAMP RELAY
2. OK: Go to next step.
INSPECT MULTIPLEX NETWORK FRONT LAMP ECU
1. Remove the front light ECU with connector.
2. Turn the front fog light switch ON.
3. Measure voltage between terminal FFOG and body ground.
OK:

Voltage: 10 - 14 V
1. OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON (See PROBLEM SYMPTOMS TABLE )
2. NG: Go to next step.
CHECK HARNESS AND CONNECTOR
1. Check for open and short circuit in harness and connector between terminal FFOG-RLY of front lamp ECU and front fog light.
2. Check for open and short circuit in harness and connector between front fog light and body ground.
1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (See ELECTRONIC CIRCUIT INSPECTION PROCEDURE )
2. OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON (See PROBLEM SYMPTOMS TABLE )