Toyota Sienna Service Manual: Problem symptoms table

Toyota Sienna Service Manual / Seat / Front power seat control system / Problem symptoms table

HINT:

Inspect the fuse and relay before confirming the suspected areas in the table below.
Inspect each suspected area in numerical order for the corresponding symptom.

If the malfunction still exists after checking and confirming that all circuits and components are normal, replace the ECU.

FRONT POWER SEAT CONTROL SYSTEM ( w/o MEMORY)

Symptom	Suspected area
Power seat does not operate (slide, front vertical, lifter, reclining).	P/SEAT fuse Power seat switch Wire harness or connector
Slide operation function only does not operate.	Power seat switch Front seat frame with adjuster (LH side slide motor) Front seat frame with adjuster (RH side slide motor) Wire harness or connector
Front vertical operation function only does not operate.	Power seat switch Front seat frame with adjuster (LH side front vertical motor) Wire harness or connector
Lifter operation function only does not operate.	Power seat switch Front seat frame with adjuster (LH side lifter motor) Wire harness or connector
Reclining operation function only does not operate.	Power seat switch Front seat frame with adjuster (LH side reclining motor) Front seat frame with adjuster (RH side reclining motor) Wire harness or connector
Lumbar support operation function only does not operate (Driver side only).	Front power seat lumbar switch Lumbar support adjuster assembly Wire harness or connector

FRONT POWER SEAT CONTROL SYSTEM ( w/ MEMORY)

Symptom	Suspected area
Power seat does not operate (manual or memorized position).	ECU power source circuit Position control ECU and switch assembly (power seat control switch and ECU)
One of the power seat functions does not operate (manual or memorized position).	Power seat motor circuit Position control ECU and switch assembly (power seat control switch and ECU)
One or all manual seat functions do not operate (memorized positions OK).	Position control ECU and switch assembly (power seat control switch
Memory function does not operate.	Memory switch circuit Multiplex communication system Position control ECU and switch assembly (power seat control switch
No memory functions operate or all memory functions operate briefly	ECU power source circuit Position control ECU and switch assembly (power seat control switch
One memory function does not operate or operates briefly and then stops	Front seat frame with adjuster (power seat motor) Position control ECU and switch assembly (power seat control switch

How to proceed with troubleshooting

HINT: Use this procedure to troubleshoot the front power seat control system. The intelligent tester should be used in steps 3 and 5. 1 VEHICLE BROUGHT TO WORKSHOP 2 CUSTOMER P ...

Terminals of ECU

1. POSITION CONTROL ECU AND SWITCH ASSEMBLY (POWER SEAT CONTROL SWITCH AND ECU) Disconnect the P58 and P59 connectors. Check the voltage of each terminal of the wire harness sid ...

Other materials:

Adjustment
HINT: On the RH side, use the same procedures as on the LH side. Since a centering bolt is used as door hinge mounting bolts on the body side and the door side, the door cannot be adjusted with them on. Substitute a bolt with a washer for the centering bolt. 1. INSPECT BACK DOOR PAN ...

Active Control Engine Mount System
DESCRIPTION LOCATION The Active Control Engine Mount (ACM) system decreases engine vibration at engine idling using the ACM VSV. The VSV is controlled by a pulse signal transmitted to the VSV from the ECM. The frequency of this pulse signal is matched to the engine speed to decrease engi ...

Folding Motor Circuit
DESCRIPTION The fold seat control ECU receives a switch operation signal from the fold seat switch and activates the folding motor. At this time, the Hall IC (seat cushion position sensor) detects the actuation signal. The fold seat control ECU uses signals from the Hall IC (seat cushion posi ...