Lexus SC300 / Lexus SC400. Manual - part 157

B. with CD player type

Is radio operating normally?

Radio receiver assembly faulty.

Is there continuity between the following terminals
with connector disconnected?

 Radio receiver amplifier B1 – Power switch 14

 Radio receiver amplifier B3 – Power switch 11

When the volume switch is turned from minu-
mum to maximum, does resistance between
terminal B1–B3 of radio receiver assembly
change from 0 to 50 k



?

is resistance value about 50 k



 between termi-

nals B3–B6 of radio receiver assembly?

Is there continuity between the following terminals
with connector disconnected?

 Radio receiver amplifier B6 – Power switch 13

Power switch faulty.

Wire harness faulty.

Power switch faulty.

Wire harness faulty.

Is there continuity between the following terminals
with connector disconnected?

 Radio receiver amplifier A1 – Power switch A6

Radio receiver as-
sembly faulty.

Wire harness faulty.

Wire harness faulty.

Power amplifier faulty.

Wire harness faulty.

Is there continuity between the following terminals
with connector disconnected?

 Power amplifier A6 – ground

Is there battery voltage between the following ter-
minals with connector disconnected?

 Power amplifier A14 – ground

 Power amplifier B10 – ground

Is there continuity between the following terminals
with connector disconnected?

 Power amplifier A7 – ground

–

BODY ELECTRICAL SYSTEM

AUDIO SYSTEM

BE–239

14

Tape player

ANY SPEAKER DOES NOT WORK (EXCEPT
WOOFER)

A. without CD player type

Is there continuity between the following terminals
with connector disconnected?

 Fr:

Radio receiver assembly A1–FR speaker 1
Radio receiver assembly A5–FR speaker 2

 FL:

Radio receiver assembly A2–FL speaker 1
Radio receiver assembly A6–FL speaker 2

 RR:

Radio receiver assembly C1–RR speaker 1
Radio receiver assembly C3–RR speaker 2

 RL:

Radio receiver assembly C2–RL speaker 1
Radio receiver assembly C6–RL speaker 2

Is there continuity between the following terminals
with connector disconnected?
 

 FR:

Radio receiver assembly A1–ground
Radio receiver assembly A5–ground

 

 FL:

Radio receiver assembly A2–ground
Radio receiver assembly A6–ground

 RR:

Radio receiver assembly C1–ground
Radio receiver assembly C3–ground

 RL:

Radio receiver assembly C2–ground
Radio receiver assembly C6–ground

Wire harness faulty

 (The wire harness for the FR speaker passes

through the transceiver, so the transceiver side
should be checked)

Wire harness faulty

 (The wire harness for the FR speaker passes

through the transceiver, so the transceiver side
should be checked)

Speaker faulty.

Radio receiver assembly faulty.

Is tape player operating normally?

Temporarily install another speaker.
Functions OK?

Radio receiver assembly faulty.

BE–240

–

BODY ELECTRICAL SYSTEM

AUDIO SYSTEM

B. with CD player type

Is there continuity between the following terminals
with connector disconnected?

 Fr:

Power amplifier B1–FR speaker 1
Power amplifier B5–FR speaker 2

 FL:

Power amplifier B2–FL speaker 1
Power amplifier B6–FL speaker 2

 RR:

Power amplifier B3–RR speaker 1
Power amplifier B4–RR speaker 2

 RL:

Power amplifier B8–RL speaker 1
Power amplifier B9–RL speaker 2

Is there continuity between the following terminals
with connector disconnected?

 FR:

Power amplifier B1–ground
Power amplifier B5–ground

 FL:

Power amplifier B2–ground
Power amplifier B6–ground

 RR:

Power amplifier B3–ground
Power amplifier B4–ground

 RL:

Power amplifier B8–ground
Power amplifier B9–ground

Wire harness faulty

 (The wire harness for the FR speaker passes

through the transceiver, so the transceiver side
should be checked)

Wire harness faulty

 (The wire harness for the FR speaker passes

through the transceiver, so the transceiver side
should be checked)

Speaker faulty.

Radio receiver assembly faulty.

Is tape player operating normally?

Temporarily install another speaker.
Functions OK?

Wire harness faulty.

Wire harness faulty.

Is there continuity between the following terminals
with connector disconnected?

 FR:

Radio receiver assembly A7–Power
amplifier A1

 FL:

Radio receiver assembly A6–Power
amplifier A2

 RR:

Radio receiver assembly A15–Power
amplifier A7

 RL:

Radio receiver assembly A14–Power
amplifier A8

Is there continuity between the following terminals
with connector disconnected?

 FR:

Radio receiver assembly A7–ground

 FL:

Radio receiver assembly A6–ground

 RR:

Radio receiver assembly A15–ground

 RL:

Radio receiver assembly A14–ground

–

BODY ELECTRICAL SYSTEM

AUDIO SYSTEM

BE–241

Radio receiver assembly faulty.

Power amplifier faulty.

Temporarily install another power amplifier.
Function is OK?

BE–242

–

BODY ELECTRICAL SYSTEM

AUDIO SYSTEM