Inspection Procedure

WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

Check voltage between terminals +B and GND of ECU connector.
PREPARATION:

Remove ECU with connectors still connected.

CHECK:

Measure voltage between terminals +B and GND of ECU connector.

OK:

Voltage: 9 - 16 V

Fig 1: Measuring Voltage Between Terminals +B And GND Of ECU Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK : Proceed to next circuit inspection shown on the problem symptoms table (See PROBLEM SYMPTOMS TABLE ).
2. NG : Go to next step.
Check continuity between terminal GND of ECU connector and body ground.
CHECK:

Measure resistance between terminal GND of ECU connector and body ground.

OK:

Resistance: 1 kΩ or less

Fig 2: Measuring Resistance Between Terminal GND Of ECU Connector And Body Ground
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Repair or replace harness or connector.
2. OK : Go to next step.
Check TI & TE fuse.
PREPARATION:

Remove TI & TE fuse from driver side J/B.

CHECK:

Check continuity of TI & TE fuse.

OK:

Continuity
1. NG : Check for short circuit in harness and all components connected to TI & TE fuse.
2. OK : Check for open circuit in harness and connector between ECU and battery (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE ).