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:
How to proceed with
troubleshooting
HINT:
Use this procedure to troubleshoot the engine immobiliser
system.
The intelligent tester should be used in steps 4, 5 and 7.
1 VEHICLE BROUGHT TO WORKSHOP
2 CUSTOMER PROBLEM ANALYSIS CHECK AND SYMPTOM CHECK
3 CRANK ENGINE FOR MORE THAN 10 SECONDS
4 CHECK FOR DTC
C ...
Problem symptoms table
WINDOW DEFOGGER SYSTEM
Symptom
Suspected area
w/ Deicer: Front window deicer does not operate.
(indicator light ON)
FR DEF fuse
Front window deicer relay
Front window deicer wire
Wire harness
w/ deicer: Front window deicer ...
Terminals of ECU
1. MULTIPLEX NETWORK GATEWAY ECU
Disconnect the G4 ECU connector.
Measure the voltage between the specified
terminals on the wire harness side connector.
If the result is not as specified, there may be a
malfunction on the wire harness side.
Measure the resistance between ...
