DESCRIPTION
This is the back-up power source for the A/C amplifier. Power is supplied even when the ignition switch is off and is used for diagnostic trouble code memory, etc.
WIRING DIAGRAM

INSPECTION PROCEDURE
1 INSPECT FUSE (ECU-B)
(a) Remove the ECU-B fuse from the engine room junction block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance


2 CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BATTERY)

(a) Disconnect the connector from the A/C amplifier.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage


PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
ACC Power Source CircuitGlossary of sae and Toyota terms
This glossary lists all SAE-J1930 terms and abbreviations
used in this manual in compliance with SAE
recommendations, as well as their TOYOTA equivalents.
...
Installation
HINT:
Use the same procedures for the RH side and LH side.
The procedures listed below are for the LH side.
1. INSTALL REAR AIRBAG SENSOR LH
Check that the ignition switch is off.
Check that the battery negative (-) terminal is
disconnected.
CAUTION:
...
Test mode procedure
1. SPEED SENSOR SIGNAL CHECK (WHEN USING SST CHECK WIRE):
HINT:
If the ignition switch is turned from the ON to the ACC
or LOCK position during Test Mode, the DTCs of the
signal check function will be erased.
(a) Turn the ignition switch off.
(b) Check that the steering wheel is in th ...