Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM1000000010Z5A
Model Year Start: 2017 Model: Sienna Prod Date Range: [08/2016 -           ]
Title: SEAT: REAR POWER SEAT CONTROL SYSTEM: Park / Neutral Position Switch Circuit; 2017 - 2020 MY Sienna [08/2016 -        ]

Park / Neutral Position Switch Circuit

DESCRIPTION

The fold seat control ECU receives signals from the park/neutral position switch assembly and controls the seat stowing and return operations. If the shift lever is in any position other than P when the engine switch is on (ACC) or on (IG), the seat cannot be operated.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuse for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.

CHECK FOLD SEAT CONTROL ECU (PARK/NEUTRAL POSITION SWITCH SIGNAL)

(a) Remove the fold seat control ECU with its connectors still connected (See page 2016 - 2020 MY Sienna [12/2015 -        ]; SEAT: POWER SEAT CONTROL ECU(for Rear No. 2 Seat): REMOVAL ).

*a

Component with harness connected

(Fold Seat Control ECU)

*b

LH Side

*c

RH Side

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

LH Side

Tester Connection

Switch Condition

Specified Condition

b2-32 (P) - Body ground

Engine switch on (ACC) or on (IG)

Shift lever in P

11 to 14 V

Engine switch on (ACC) or on (IG)

Shift lever not in P

Below 1 V

RH Side

Tester Connection

Switch Condition

Specified Condition

a2-32 (P) - Body ground

Engine switch on (ACC) or on (IG)

Shift lever in P

11 to 14 V

Engine switch on (ACC) or on (IG)

Shift lever not in P

Below 1 V

(c) Reinstall the fold seat control ECU.

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

2.

CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH - BATTERY)

(a) Disconnect the B66 park/neutral position switch connector.

*a

Front view of wire harness connector

(to Park/Neutral Position Switch Assembly)

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

B66-1 (RB) - Body ground

Engine switch off

Below 1 V

Engine switch on (ACC) or on (IG)

11 to 14 V

(c) Reconnect the park/neutral position switch connector.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY

(a) Remove the park/neutral position switch assembly.

for 2WD: Click here 2017 - 2020 MY Sienna [08/2016 -        ]; UA80E (AUTOMATIC TRANSMISSION / TRANSAXLE): PARK / NEUTRAL POSITION SWITCH: REMOVAL

for 4WD: Click here 2017 - 2020 MY Sienna [08/2016 -        ]; UA80F (AUTOMATIC TRANSMISSION / TRANSAXLE): PARK / NEUTRAL POSITION SWITCH: REMOVAL

*a

Component without harness connected

(Park/Neutral Position Switch Assembly)

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

1 (RB) - 3 (PL)

Shift lever in P

Below 1 Ω

Shift lever not in P

10 kΩ or higher

(c) Reinstall the park/neutral position switch assembly.

Result

Proceed to

OK

A

NG (for 2WD)

B

NG (for 4WD)

C
B

REPLACE PARK/NEUTRAL POSITION SWITCH

C

REPLACE PARK/NEUTRAL POSITION SWITCH

A

4.

CHECK HARNESS AND CONNECTOR (FOLD SEAT CONTROL ECU - PARK/NEUTRAL POSITION SWITCH)

(a) Disconnect the b2 or a2 fold seat control ECU connector.

(b) Disconnect the B66 park/neutral position switch assembly connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

LH Side

Tester Connection

Condition

Specified Condition

b2-32 (P) - B66-3 (PL)

Always

Below 1 Ω

b2-32 (P) - Body ground

Always

10 kΩ or higher

RH Side

Tester Connection

Condition

Specified Condition

a2-32 (P) - B66-3 (PL)

Always

Below 1 Ω

a2-32 (P) - Body ground

Always

10 kΩ or higher

(d) Reconnect the park/neutral position switch assembly connector.

(e) Reconnect the fold seat control ECU connector.

OK

REPLACE FOLD SEAT CONTROL ECU

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR