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:
Vehicle Speed Signal Error (Test Mode DTC)
DTC C2191/91 Vehicle Speed Signal Error (Test Mode DTC)
DESCRIPTION
The tire pressure warning ECU receives a speed signal from the combination
meter. This DTC is stored
upon entering test mode, and cleared when a vehicle speed signal of 12 mph (20
km/h) is detected for 3
seconds or more. Thi ...
Diagnosis system
1. CHECK DLC3
The vehicle's ECU uses ISO 15765-4 for
communication protocol. The terminal arrangement
of the DLC3 complies with SAE J1962 and matches
the ISO 15765-4 format.
NOTICE:
*: Before measuring the resistance, leave the
vehicle as is for at least 1 minute and do ...
Fail-safe chart
1. FAIL-SAFE
This function minimizes the loss of the ECT functions
when any malfunction occurs in a sensor or solenoid.
(a) ATF (Automatic Transmission Fluid) temperature
sensor:
When the ATF temperature sensor has a
malfunction, 5th upshift is prohibited.
(b) Counter gear speed sensor NC ...
