2000 LEXUS GS400 ignition

27 Noise NOISE PRODUCED BY VIBRATION OR SHOCK WHILE DRIVING
No
Ye s Is speaker properly installed?
Noise is produced from static eletricity accumulating in the vehicle body. With vehicles stationary lightly tap each system.
Is noise produced?Install properly.
Each system faulty. Is speaker properly installed?
No
No Ye s
Ye s
28 Noise NOISE PRODUCED WHEN ENGINE STARTS
NoYe s Whistling noise which becomes high±pitched when
accelerator strongly depressed, disappears shortly
after engine stops.Generator noise.
A/C noise.
Fuel gauge noise.
Horn noise.
Ignition noise.
Turn signal noise.
Washer noise.
Engine coolant temp. gauge noise.
Wiper noise. Whining noise occurs when A/C is operating.
Scratching noise occurs during sudden acceleration, driving on rough
roads or when ignition switch is turned ON.
Clicking sound is heard when horn button is pressed, then
released. Whirring/grating sound is heard when pushed
continuously.
Murmuring sound stops when engine stops.
Tick±tack noise occurs in co±ordination with blinking
offlasher.
Noise occurs during window washer operation.
Scratching noise occurs while engine is running,
and continues a while even after engine stops.
Scraping noise in line with wiper beat.
Other type of noiseYe s
Ye s
Ye s
Ye s
Ye s
Ye s
Ye s
Ye s No
No
No
No
No
No
No
No
± BODY ELECTRICALAUDIO SYSTEM
BE±215
2516 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

BE±22
± BODY ELECTRICALPOWER SOURCE
2323 Author: Date:
2000 LEXUS GS300/GS400 (RM718U) ECU±B1 30 ± Ground
ConstantBattery positive voltage
HTR 31 ± GroundConstantBattery positive voltage
FAN MAIN 33 ± GroundConstantBattery positive voltage
CDS FAN 35 ± GroundIgnition switch ONBattery positive voltage
RAD FAN 35 ± GroundIgnition switch ONBattery positive voltage
H±LP R LWR 38 ± GroundLight control switch HEADBattery positive voltage
H±LP L LWR 38 ± GroundLight control switch HEADBattery positive voltage
H±LP R UPR 38 ± GroundLight control switch HEADBattery positive voltage
H±LP L UPR 42 ± GroundLight control switch HEADBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.
(b) Remove the relay from the junction block and inspect the
connector on junction block side.
Relay Tester connectionConditionSpecified condition
H±LP 44 ± GroundConstantBattery positive voltage
H±LP 46 ± GroundConstantBattery positive voltage
ST 48 ± GroundConstantContinuity
ST 51 ± GroundConstantBattery positive voltage
EFI MAIN 53 ± GroundConstantContinuity
EFI MAIN 55 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.

I05032
± BODY ELECTRICALPOWER SOURCE
BE±23
2324 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
2. INSPECT ENGINE ROOM No.3 RELAY BLOCK CIR-
CUIT
Remove the relay from the relay block and inspect the connec-
tor on relay block side.
Fuse Tester connectionConditionSpecified condition
FAN NO.1 3 ± GroundIgnition switch ONBattery positive voltage
FAN NO.2 8 ± GroundIgnition switch ONBattery positive voltage
A/C COMP 13 ± GroundIgnition switch ONBattery positive voltage
FAN NO.3 17 ± GroundIgnition switch ONBattery positive voltage
DIMMER 20 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.

BE±26
± BODY ELECTRICALPOWER SOURCE
2327 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(a) Remove the fuse from the junction block and inspect the
connector on junction block side.
Fuse Tester connectionConditionSpecified condition
AM1 1 ± GroundConstantBattery positive voltage
WASHER 3 ± GroundIgnition switch ONBattery positive voltage
FOG 5 ± GroundConstantBattery positive voltage
TAIL 7 ± GroundLight control switch TAIL or HEADBattery positive voltage
SRS±ACC 9 ± GroundIgnition switch ACC or ONBattery positive voltage
GAUGE 11 ± GroundIgnition switch ONBattery positive voltage
FUEL OPN 13 ± GroundConstantBattery positive voltage
D FR DOOR 15 ± GroundConstantBattery positive voltage
PANEL 17 ± GroundLight control switch TAIL or HEADBattery positive voltage
HTR 19 ± GroundIgnition switch ONBattery positive voltage
SRS±B 21 ± GroundConstantBattery positive voltage
P/SEAT (D) 23 ± GroundConstantBattery positive voltage
RAD NO.2 25 ± GroundIgnition switch ACC or ONBattery positive voltage
WIP 27 ± GroundIgnition switch ONBattery positive voltage
OBD 29 ± GroundConstantBattery positive voltage
STOP 31 ± GroundConstantBattery positive voltage
CIG 33 ± GroundIgnition switch ACC or ONBattery positive voltage
ECU±IG 35 ± GroundIgnition switch ONBattery positive voltage
ST 37 ± GroundIgnition switch ONBattery positive voltage
IGN 39 ± GroundIgnition switch ONBattery positive voltage
D RR DOOR 41 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.
(b) Remove the relay from the junction block and inspect the
connector on junction block side.
Relay Tester connectionConditionSpecified condition
Fog light 43 ± GroundConstantBattery positive voltage
Fog light 44 ± GroundConstantContinuity
Fog light 46 ± GroundLight control switch HEADBattery positive voltage
Taillight 47 ± GroundConstantBattery positive voltage
Taillight 48 ± GroundConstantContinuity
Taillight 50 ± GroundConstantContinuity
If the circuit is not as specified, inspect the circuits connected
to other parts.

BE±28
± BODY ELECTRICALPOWER SOURCE
2329 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(a) Remove the fuse from the junction block and inspect the
connector on junction block side.
Fuse Tester connectionConditionSpecified condition
DEF 1 ± GroundConstantBattery positive voltage
MIR HTR 7 ± GroundIgnition switch ONBattery positive voltage
S/ROOF 13 ± GroundConstantBattery positive voltage
P FR DOOR 15 ± GroundConstantBattery positive voltage
P/SEAT (P) 23 ± GroundConstantBattery positive voltage
DOME 25 ± GroundConstantBattery positive voltage
S±HTR 27 ± GroundIgnition switch ONBattery positive voltage
TV 31 ± GroundConstantBattery positive voltage
ECU±B2 33 ± GroundConstantBattery positive voltage
P FR DOOR 41 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.
(b) Remove the relay from the junction block and inspect the
connector on junction block side.
Relay Tester connectionConditionSpecified condition
Ignition Main 43 ± GroundIgnition switch ONBattery positive voltage
Mirror Heater 47 ± GroundIgnition switch ONBattery positive voltage
Mirror Heater 50 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.

BE0GD±10
I01372
Ignition SwitchRadio Assembly Tweeter
Front Speakers
Rear Speakers
Tweeter
Radio Assembly LEXUS Navigatioin
System Woofer
Power Amplifier
(NAKAMICHI made)
Driver Side Junction Block

RAD NO.2 FuseEngine Room No.1
Junction Block

ECU±B1 Fuse

RAD NO.1 Fuse
Passenger Side
Junction Block

DOME Fuse CD Auto ChangerCD Magazine
Power Amplifier
(PIONEER made)
BE±216
± BODY ELECTRICALAUDIO SYSTEM
2517 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
LOCATION
The vehicle shown in this illustration is ºGS400º.
All components of ºGS300º other than the ones used for engine are same as ºGS400º.

BE0GE±03
I04310
Wire Harness Side
I04189
Wire Harness Side
Connector ºBº
Connector ºDº Connector ºCº Connector ºAº
± BODY ELECTRICALAUDIO SYSTEM
BE±217
2518 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. Except NAKAMICHI made:
INSPECT CD AUTO CHANGER CIRCUIT
Disconnect connectors from CD auto changer and inspect the
connector on the wire harness side.
Tester connectionConditionSpecified condition
8 ± GroundConstantContinuity
5 ± GroundConstantBattery positive voltage
10 ± GroundIgnition switch LOCKNo voltage
10 ± GroundIgnition switch ACC or ONBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.
HINT:

Check the wire harness between the radio receiver as-
sembly and the CD auto changer.

Since the signals to and from the MUTE, R±, R+, L±, L+,
TX
± and TX+ terminals are serial signals, they cannot or-
dinarily be measured with a tester.
2. Except NAKAMICHI made:
INSPECT POWER AMPLIFIER CIRCUIT
Disconnect the connector from power amplifier and inspect the
connector on the wire harness side.
Tester connectionConditionSpecified condition
B7 ± GroundConstantContinuity
C12 ± GroundIgnition switch LOCK and radio switch ONNo voltage
C12 ± GroundIgnition switch ACC or ON and radio switch ONBattery positive voltage
B4 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.

I04190
Wire Harness Side
Connector ºAº Connector ºBº BE±218
± BODY ELECTRICALAUDIO SYSTEM
2519 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
3. Except NAKAMICHI made:
INSPECT RADIO RECEIVER ASSEMBLY CIRCUIT
Disconnect the connectors from the radio receiver assembly,
and inspect the connector on the wire harness side.
Tester connectionConditionSpecified condition
A2 ± GroundConstantContinuity
A4 ± GroundConstantBattery positive voltage
A1 ± GroundIgnition switch LOCKNo voltage
A1 ± GroundIgnition switch ACC or ONBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.
HINT:
Check the wire harness between radio receiver assembly and
the CD auto changer, between radio receiver assembly and
power amplifier.