Toyota Sienna Service Manual: Back-up Power Source Circuit
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 Circuit
DESCRIPTION
This circuit supplies power to the A/C amplifier and the illumination for the
clock.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 INSPECT FUSE (ECU ACC)
(a) Remove the ECU ACC fuse fr ...
Other materials:
Open in ABS Solenoid Relay Circuit
DESCRIPTION
This relay supplies power to each ABS solenoid.
Immediately after the ignition switch is turned to the ON position, the relay
turns on if the solenoid is
determined to be normal as a result of self-diagnosis during initial check.
The relay turns off if an open/short is dete ...
ECM Power Source Circuit
DESCRIPTION
When the ignition switch is turned to the ON position, the battery voltage is
applied to terminal IGSW of
the ECM. The ECM MREL output signal causes a current to flow to the coil,
closing the contacts of the EFI
relay and supplying power to terminal +B of the ECM.
If the igniti ...
Installation
1. INSTALL OCCUPANT CLASSIFICATION ECU
Check that the ignition switch is off.
Check that the negative battery (-) terminal is
disconnected.
CAUTION:
After disconnecting the negative battery
terminal, wait for at least 90 seconds before
starting the operation.
...
