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:

Open in One Side of CAN Branch Line
DESCRIPTION If 2 or more ECUs and/or sensors do not appear on the intelligent tester "Communication Bus Check" screen, one side of the CAN branch wire may be open. (One side of the CAN-H [branch wire] / CAN-L [branch wire] of the ECU and/or sensor is open.) Symptom ...

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 not oper ...

Short in Side Squib LH Circuit
DTC B0115/47 Short in Side Squib LH Circuit DESCRIPTION The side squib LH circuit consists of the center airbag sensor assembly and the front seat side airbag assembly LH. This circuit instructs the SRS to deploy when deployment conditions are met. DTC B0115/47 is recorded when a short ci ...