Toyota Sienna Service Manual: ECU Power Source Circuit
DESCRIPTION
The position control ECU and switch assembly (power seat control switch and ECU) is contained in the switch assembly.
During manual operation, only one switch signal is accepted. If signals are input from 2 or more switches simultaneously, all of them are ignored, except when signals are input from the front vertical switch and lifter switch simultaneously. In this case, the signal from the lifter will operate.
During automatic operation, a manual switch input will override any other operations, i.e. automatic operations will stop and the manual input operation only will be accepted. For example, if a manual switch input is activated during a seat store/restore operation, the previous operation will cease and manual operation will be performed. After the manual operation is performed, the previous automatic operation will not resume.
The power mirror store/restore operation is unaffected by manual switch inputs.
The front power seat switch does not allow the restore operation of the power seat when the system detects that the voltage of terminal SYSB is less than 8.0 +- 0.5 V for 30 msec. or is more than 10 +- 0.5 V for 30 msec.
This circuit is the power source circuit for the position control ECU and switch assembly (power seat control switch and ECU).
HINT:
- Manual adjustment of the slide and reclining can be performed even when the front power seat switch is not functional if current is allowed to flow into terminals +B and SYSB.
- The lumber support function can always be used because its circuit does not include the ECU and differs from other functions (reclining, slide, lifter, and front vertical functions.)
WIRING DIAGRAM
INSPECTION PROCEDURE
1 INSPECT POSITION CONTROL ECU AND SWITCH ASSEMBLY (POWER SEAT CONTROL SWITCH AND ECU POWER SOURCE CIRCUIT)
- Disconnect the position control ECU and switch assembly connectors.
- Measure the voltage according to the value(s) in the table below.
Standard voltage
2 INSPECT POSITION CONTROL ECU AND SWITCH ASSEMBLY (POWER SEAT CONTROL SWITCH AND ECU GROUND CIRCUIT)
- Measure the resistance according to the value(s) in the table below.
Standard resistance
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
Driving Position Memory Switch Circuit (w/ Memory)
DESCRIPTION
The seat memory switch sends signals to the outer mirror control ECU LH via
the multiplex
communication system to memorize a given seat position. This memory system does
not use a po ...
Seat heater system
PARTS LOCATION
...
Other materials:
Removal
1. REMOVE EXHAUST PIPE ASSEMBLY
(a) Remove exhaust pipe assembly (See page EX-8).
2. REMOVE PROPELLER W/CENTER BEARING SHAFT ASSEMBLY
(a) Depress the brake pedal and hold it down.
(b) Using a hexagon wrench (6 mm), loosen the cross
groove joint set bolts a half turn.
HINT:
Place a cloth ...
Unlock Warning Switch Circuit
DESCRIPTION
The unlock warning switch detects if the key is in the ignition key cylinder.
The unlock warning switch turns on when the key is inserted into the ignition
key cylinder and turns off
when the key is removed from the cylinder.
The body ECU is connected to the unlock warning swit ...
Reassembly
1. INSTALL FRONT OIL PUMP OIL SEAL
(a) Using SST and a hammer, install a new oil seal to
the oil pump body.
SST 09350-32014 (09351-32140)
HINT:
The seal end should be flat with the outer edge of
the oil pump.
(b) Coat the lip of the oil seal with MP grease.
2. INSTALL FRONT OIL PUMP BODY ...
