Last Modified: 04-05-2023 6.11:8.1.0 Doc ID: RM100000000VIMJ
Model Year Start: 2016 Model: Sienna Prod Date Range: [12/2015 - 08/2016]
Title: U660F (AUTOMATIC TRANSMISSION / TRANSAXLE): AUTOMATIC TRANSAXLE SYSTEM: P0746; Pressure Control Solenoid "A" Performance (Shift Solenoid Valve SL1); 2016 MY Sienna [12/2015 - 08/2016]

DTC

P0746

Pressure Control Solenoid "A" Performance (Shift Solenoid Valve SL1)

DESCRIPTION

The TCM uses the vehicle speed signal and signals from the transmission speed sensors (NC, NT) to detect the actual gear (1st, 2nd, 3rd, 4th, 5th or 6th gear).

Then the TCM compares the actual gear with the shift schedule in the TCM memory to detect mechanical problems of the shift solenoid valves and valve body.

DTC No.

DTC Detection Condition

Trouble Area

P0746

The engine revs freely when 1st, 2nd, 3rd, or 4th gear is commanded (2 trip detection logic).

When either of the following is detected twice (2 trip detection logic):

  • When 5th gear is commanded, 4th gear is engaged.
  • When 6th gear is commanded, 4th gear is engaged
  • Shift solenoid valve SL1 remains open or closed
  • Valve body is blocked
  • Automatic transaxle (clutch, brake or gear etc.)

MONITOR DESCRIPTION

The TCM commands gear shifts by turning the shift solenoid valves on and off. According to the engine speed (NE), input speed (NT) and output speed (NC), the TCM detects the actual gear (1st, 2nd, 3rd, 4th, 5th or 6th gear). When the gear commanded by the TCM and the actual gear are not the same, the TCM will turn on the MIL and store the DTC.

MONITOR STRATEGY

Related DTCs

P0746:

Shift solenoid valve SL1 OFF malfunction

Shift solenoid valve SL1 ON malfunction

Required sensors/Components

Shift solenoid valve SL1, Input speed sensor (NT), Output speed sensor (NC), Crankshaft position sensor (NE)

Frequency of operation

Continuous

Duration

ON malfunction: 0.8 seconds

OFF malfunction: 0.5 seconds

MIL operation

2 driving cycles

Sequence of operation

None

TYPICAL ENABLING CONDITIONS

ALL:

The monitor will run whenever this DTC is not present.

(Not circuit malfunction)

P0712, P0713 (ATF temperature sensor circuit (TFT sensor))

P0115, P0117, P0118 (ECT sensor circuit)

P0715, P0717 (Input speed sensor (NT) circuit)

P0791, P0793 (Output speed sensor (NC) circuit)

P0748 (Shift solenoid valve SL1 circuit)

P0778 (Shift solenoid valve SL2 circuit)

P0798 (Shift solenoid valve SL3 circuit)

P2810 (Shift solenoid valve SL4 circuit)

P0327, P0328, P0332, P0333 (KCS sensor circuit)

P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0604, P0606, P060A, P060B, P060D, P060E, P0657, P1607, P2102, P2103, P2111, P2112, P2118, P2119, P2135 ((ETCS) Electronic throttle control system)

U0100 (CAN communication system)

Transmission range

D

TFT (Transmission fluid temperature)

-10°C (14°F) or more

TFT (Transmission fluid temperature) sensor circuit

No circuit malfunction

ECT (Engine coolant temperature) sensor circuit

No circuit malfunction

Input speed sensor (NT) circuit

No circuit malfunction

Output speed sensor (NC) circuit

No circuit malfunction

Shift solenoid valve SL1 circuit

No circuit malfunction

Shift solenoid valve SL2 circuit

No circuit malfunction

Shift solenoid valve SL3 circuit

No circuit malfunction

Shift solenoid valve SL4 circuit

No circuit malfunction

KCS (Knock control sensor circuit)

No circuit malfunction

(ETCS) Electronic throttle control system

Not system down

CAN communication system

Not system down

Engine

Starting

OFF malfunction:

TCM selected gear

1st, 2nd, 3rd or 4th

TCM indicated pressure value of SL1

1200 kPa

Throttle valve opening angle

3% or more

ON malfunction:

TCM selected gear

5th or 6th

Vehicle speed

2 km/h (1.2 mph) or more

Engine coolant temperature

40°C (104°F) or more

Throttle valve opening angle

4.5% or more at engine speed 2000 rpm

(Varies with engine speed)

TYPICAL MALFUNCTION THRESHOLDS

Either of the following conditions is met:

  • OFF malfunction:

    Input speed (NT) - Output speed (NC) x Gear ratio

    1000 rpm or more

    ON malfunction:

    Input speed (NT) / Output speed (NC) when output speed less than 1000 rpm

    0.998 to 1.138

CAUTION / NOTICE / HINT

NOTICE:

Perform the universal trip to clear permanent DTCs (See page 2016 MY Sienna [12/2015 - 08/2016]; U660F (AUTOMATIC TRANSMISSION / TRANSAXLE): AUTOMATIC TRANSAXLE SYSTEM: DTC CHECK / CLEAR ).

PROCEDURE

1.

CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0746)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / ECT / Trouble Codes.

(e) Read the DTCs using the Techstream.

Result

Result

Proceed to

P0746 and other DTCs are output

A

Only P0746 is output

B

HINT:

If a solenoid is stuck OFF, DTCs for several solenoids including the malfunctioning solenoid will be detected.

B

GO TO STEP 3

A

2.

PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE SHIFT POSITION)

NOTICE:

This test should always be performed with at least 2 people.

(a) Warm up the engine.

(b) Turn the ignition switch off.

(c) Connect the Techstream to the DLC3.

(d) Turn the ignition switch to ON.

(e) Turn the Techstream on.

(f) Enter the following menus: Powertrain / ECT / Active Test.

(g) According to the display on the Techstream, perform the Active Test.

HINT:

Comparing the gear commanded by the Active Test with the actual gear enables confirmation of the problem (See page 2016 MY Sienna [12/2015 - 08/2016]; U660F (AUTOMATIC TRANSMISSION / TRANSAXLE): AUTOMATIC TRANSAXLE SYSTEM: FAIL-SAFE CHART ).

ECT

Tester Display

Test Part

Control Range

Diagnostic Note

Control the Shift Position

Operates the shift solenoid valves to allow gears to selected manually.
  • Press "→" button: Upshift occurs
  • Press "←" button: Downshift occurs

Can be used to check the operation of the shift solenoid valves.

Upshifts and downshifts should be performed consecutively. A 10-second interval is required between gear changes.

Do not downshift at high speeds. Doing so will damage the automatic transaxle.

[Vehicle Condition]

  • 50 km/h (30 mph) or less

NOTICE:

  • This test can be conducted when the vehicle is stopped.
  • When shifting gears using the Active Test function, do not operate the accelerator pedal for 2 seconds before and after shifting gears.

HINT:

The gear commanded by the TCM is shown in the Data List / Shift Status display on the Techstream.

(h) Check the vehicle speed and the gear when the engine speed is 1000 rpm.

HINT:

Because the torque converter clutch has not engaged, it may be difficult to obtain the speeds specified in 4th, 5th, and 6th gear, however a difference of speed should still be evident following each gear change.

Standard:

1st

2nd

3rd

4th

5th

6th

8 to 12 km/h

(5 to 7.5 mph)

15 to 19 km/h

(9.3 to 11.8 mph)

21 to 25 km/h

(13.0 to 15.5 mph)

31 to 35 km/h

(19.3 to 21.7 mph)

44 to 48 km/h

(27.3 to 29.8 mph)

52 to 56 km/h

(32.3 to 34.8 mph)

(i) Compare the TCM commanded gear and the actual gear.

Result

Actuator Gear during Malfunction

TCM Commanded Gear

Proceed to

1st

2nd

3rd

4th

5th

6th

Shift solenoid SL1

Stuck ON

1st

2nd

3rd

4th

4th

4th

A

Stuck OFF

N*1

N*1

N*1

N*1

5th

6th

Shift solenoid SL2

Stuck ON

4th

4th

4th

4th

5th

6th

B

Stuck OFF

1st

2nd

3rd

1st

N*1

N*1

Shift solenoid SL3

Stuck ON

2nd

2nd

3rd

4th

5th

6th

C

Stuck OFF

1st

1st

3rd

4th

5th

N*1

Shift solenoid SL4

Stuck ON*3

3rd

3rd

3rd

4th

5th

5th

D

Stuck OFF

1st

2nd

1st

4th

N*1

6th

Shift solenoid SLT

Stuck ON

N*2

N*2

N*2

N*2

N*2

N*2

E

Stuck OFF*3

1st

2nd

3rd

4th

5th

6th

HINT:

  • *1: Neutral
  • *2: If shift solenoid SLT is stuck on, the line pressure will be low. Therefore, the amount of torque that can be transmitted by each gear is lower than the normal limit. When the engine power exceeds this lowered limit, the engine speed will increase freely.
  • *3: When shift solenoid SLT is stuck off, gear shifting is normal.
B

GO TO DTC CHART (RELATED SHIFT SOLENOID VALVE (SL2) PERFORMANCE DTC P0776)

C

GO TO DTC CHART (RELATED SHIFT SOLENOID VALVE (SL3) PERFORMANCE DTC P0796)

D

GO TO DTC CHART (RELATED SHIFT SOLENOID VALVE (SL4) PERFORMANCE DTC P2808)

E

GO TO DTC CHART (RELATED SHIFT SOLENOID VALVE (SLT) PERFORMANCE DTC P2714)

A

3.

INSPECT SHIFT SOLENOID VALVE SL1

(a) Remove shift solenoid valve SL1.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

1 - 2

20°C (68°F)

5.0 to 5.6 Ω

Text in Illustration

*a

Component without harness connected

(Shift Solenoid Valve SL1)

(c) Connect a battery positive (+) lead with a 21 W bulb to terminal 2 and a negative (-) lead to terminal 1 of the solenoid valve connector. Then check that the valve moves and makes an operating sound.

OK:

Valve moves and makes an operating sound.

NG

REPLACE SHIFT SOLENOID VALVE SL1

OK

4.

INSPECT TRANSMISSION VALVE BODY ASSEMBLY

(a) Check the transmission valve body assembly (See page 2016 MY Sienna [12/2015 - 08/2016]; U660F (AUTOMATIC TRANSMISSION / TRANSAXLE): VALVE BODY ASSEMBLY(When Not Using the Engine Support Bridge): REMOVAL ).

OK:

There are no foreign objects on each valve and they operate smoothly.

OK

REPLACE AUTOMATIC TRANSAXLE ASSEMBLY

NG

REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY