Last Modified: 11-29-2007 1.6 C
Service Category: Drivetrain Section: Automatic Transmission/Transaxle
Model Year: 2008 Model: Sequoia Doc ID: RM000000W8204FX
Title: AB60E AUTOMATIC TRANSMISSION / TRANSAXLE: AUTOMATIC TRANSMISSION SYSTEM: DESCRIPTION (2008 Sequoia)

DTC

P0766

Shift Solenoid "D" Performance (Shift Solenoid Valve S4)

DTC

P0776

Pressure Control Solenoid "B" Performance (Shift Solenoid Valve SL2)

DESCRIPTION

The ECM uses signals from the output shaft speed sensor and input speed sensor to detect the actual gear position (1st, 2nd, 3rd, 4th, 5th or 6th gear).

Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical problems of the shift solenoid valves, valve body or automatic transmission (clutch, brake or gear, etc.).

DTC No.

DTC Detection Condition

Trouble Area

P0766

S4 stuck OFF malfunction or brake control valve malfunction*:

Shifting to 5th and 6th gears is impossible.

The ECM determines there is a malfunction when the following conditions are both met. (2-trip detection logic)

(a) When the ECM directs the transmission to switch to 5th gear, the actual gear is shifted to 4th.

(b) When the ECM directs the transmission to switch to 6th gear, the actual gear is shifted to 4th.
  • Shift solenoid valve S4 remains closed
  • Shift solenoid valve SLT remains open or closed
  • Valve body is blocked (Brake control valve)
  • Automatic transmission (clutch, brake or gear, etc.)

P0776

SL2 stuck ON malfunction or brake control valve malfunction*:

Shifting to 5th and 6th gears is impossible.

The ECM determines there is a malfunction when the following conditions are both met. (2-trip detection logic)

(a) When the ECM directs the transmission to switch to 5th gear, the actual gear is shifted to 4th.

(b) When the ECM directs the transmission to switch to 6th gear, the actual gear is shifted to 4th.
  • Shift solenoid valve SL2 remains open
  • Shift solenoid valve SLT remains open or closed
  • Valve body is blocked (Brake control valve)
  • Automatic transmission (clutch, brake or gear, etc.)

HINT:

  • Gear positions in the event of a solenoid valve mechanical problem:

    ECM command gearshift

    1st

    2nd

    3rd

    4th

    5th

    6th

    *: Actual gear position under malfunction

    1st

    2nd

    3rd

    4th

    4th

    4th
  • Gear position during fail-safe operation:

    If any malfunction is detected, the ECM changes into the fail-safe mode to shift into the gear positions as shown in the table below.

    Gear position under normal conditions

    1st

    2nd

    3rd

    4th

    5th

    6th

    *: Actual gear position under fail-safe mode

    1st

    2nd

    3rd

    3rd

    3rd

    3rd

MONITOR DESCRIPTION

This DTC indicates "stuck OFF malfunction" of the shift solenoid valve S4, "stuck ON malfunction" of the shift solenoid valve SL2, or brake control valve malfunction. The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF". When the gear position commanded by the ECM and the actual gear position are not same, the ECM illuminates the MIL and stores the DTCs.

MONITOR STRATEGY

Related DTCs

P0766: Shift solenoid valve S4/OFF malfunction

P0776: Shift solenoid valve SL2/ON malfunction

Required sensors/Components

Shift solenoid valve S4, Speed sensor (NT), Speed sensor (SP2), Crankshaft position sensor (NE)

Frequency of operation

Continuous

Duration

0.4 seconds

MIL operation

2 driving cycles

Sequence of operation

None

TYPICAL ENABLING CONDITIONS

All

The monitor will run whenever the following DTCs are not present

P0115 - P0118: ECT sensor

P0125: Insufficient ECT for Closed Loop

P0500: VSS

P0748 - P0799: Trans solenoid (range)

Turbine speed sensor circuit

Not circuit malfunction

Output speed sensor circuit

Not circuit malfunction

Shift solenoid valve S1 circuit

Not circuit malfunction

Shift solenoid valve S2 circuit

Not circuit malfunction

Shift solenoid valve S3 circuit

Not circuit malfunction

Shift solenoid valve S4 circuit

Not circuit malfunction

Shift solenoid valve SR circuit

Not circuit malfunction

Shift solenoid valve SL1 circuit

Not circuit malfunction

Shift solenoid valve SL2 circuit

Not circuit malfunction

ECT (Engine coolant temperature) sensor circuit

Not circuit malfunction

KCS sensor circuit

Not circuit malfunction

ETCS (Electric Throttle Control System)

Not system down

Transmission position

"D"

Duration time from shifting "N" to "D"

4 seconds or more

ECT

40°C (104°F) or more

Spark advance from max. retard timing by KCS control

0° crankshaft angle or more

Engine

Starting

P0766 OFF Malfunction (A) and P0776 ON Malfunction (A)

ECM selected gear

5th

Vehicle speed

2 km/h (1.3 mph) or more

Throttle valve opening angle

9% or more at 2000 rpm

(Conditions vary with engine speed)

P0766 OFF Malfunction (B) and P0776 ON Malfunction (B)

ECM selected gear

6th

Vehicle speed

2 km/h (1.3 mph) or more

Throttle valve opening angle

9% or more at 2000 rpm

(Conditions vary with engine speed)

TYPICAL MALFUNCTION THRESHOLDS

[OFF malfunction]

Both of the following conditions are met: OFF malfunction (A) and (B)

P0766 OFF Malfunction (A)

Turbine speed/Output speed (NT/NO)

0.93 or more, and 1.07 or less

(This means actual gear is 4th)

P0766 OFF Malfunction (B)

Turbine speed/Output speed (NT/NO)

0.93 or more, and 1.07 or less

(This means actual gear is 4th)

[ON malfunction]

Both of the following conditions are met: ON malfunction (A) and (B)

P0776 ON Malfunction (A)

Turbine speed/Output speed (NT/NO)

0.93 or more, and 1.07 or less

(This means actual gear is 4th)

P0776 ON Malfunction (B)

Turbine speed/Output speed (NT/NO)

0.93 or more, and 1.07 or less

(This means actual gear is 4th)

INSPECTION PROCEDURE

1. ACTIVE TEST

HINT:

Using the Techstream to perform Active Tests allows relays, VSVs, actuators and other items to be operated without removing any parts. This non-intrusive functional inspection can be very useful because intermittent operation may be discovered before parts or wiring is disturbed. Performing Active Tests early in troubleshooting is one way to save diagnostic time. Data List information can be displayed while performing Active Tests.

(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 / Engine and ECT / Active Test.

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

HINT:

While driving, the shift position can be forcibly changed with the Techstream.

Comparing the shift position commanded by the Active Test with the actual shift position enables you to confirm the problem AB60E AUTOMATIC TRANSMISSION / TRANSAXLE: AUTOMATIC TRANSMISSION SYSTEM: FAIL-SAFE CHART (2008 Sequoia) .

Engine and ECT

Tester Display

Test Part

Control Range

Diagnostic Note

Control the Shift Position

Operate shift solenoid valve and set each shift position by yourself
  • Press "→" button: Shift up
  • Press "←" button: Shift down

Possible to check operation of shift solenoid valves

[Vehicle Condition]

50 km/h (30 mph) or less

HINT:

  • This test can be conducted when the vehicle speed is 50 km/h (30 mph) or less.
  • The 4th to 5th and 5th to 6th up-shift must be performed with the accelerator pedal released.
  • The 6th to 5th and 5th to 4th down-shift must be performed with the accelerator pedal released.
  • Do not operate the accelerator pedal for at least 2 seconds after shifting and do not shift successively.
  • The shift position commanded by the ECM is shown in the Data List display on the Techstream.
  • The shift solenoid valve SL2 turns ON/OFF normally when the shift lever is in D.

    ECM command gearshift

    1st

    2nd

    3rd

    4th

    5th

    6th

    Shift solenoid valve S4

    OFF

    OFF

    OFF

    OFF

    ON

    ON

    Shift solenoid valve SL2

    ON

    ON

    ON

    ON

    OFF

    OFF

PROCEDURE

1.

CHECK DTC OUTPUT (IN ADDITION TO DTCS P0766 AND P0776)

(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 / Engine and ECT / Trouble Codes.

(e) Read the DTCs using the Techstream.

Result

Result

Proceed to

Only P0766 and P0776 are output

A

P0766, P0776 and other DTCs are output

B

HINT:

If any other codes besides P0766 and P0776 are output, perform troubleshooting for those DTCs first.

A

2.

PERFORM ACTIVE TEST USING TECHSTREAM (SHIFT SOLENOID VALVE SLT)

NOTICE:

  • Perform the test at the normal operating ATF temperature: 50 to 80°C (122 to 176°F).
  • Be careful to prevent SST hose from interfering with the exhaust pipe.
  • Perform the test with the A/C OFF.

HINT:

Using the Techstream to perform Active Tests allows relays, VSVs, actuators and other items to be operated without removing any parts. This non-intrusive functional inspection can be very useful because intermittent operation may be discovered before parts or wiring is disturbed. Performing Active Tests early in troubleshooting is one way to save diagnostic time. Data List information can be displayed while performing Active Tests.

(a) Remove the test plug on the transmission case center right side and connect SST.

SST: 09992-00095

09992-00231

09992-00271

(b) Connect the Techstream to the DLC3.

(c) Start the engine and warm it up.

(d) Measure the line pressure with SST.

(e) Turn the Techstream on.

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

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

(h) Measure the line pressure.

Engine and ECT

Tester Display

Test Part

Control Range

Diagnostic Note

Activate the Solenoid (SLT)*

Operate the shift solenoid SLT and raise line pressure

ON or OFF

HINT:

  • OFF: Line pressure up (when Active Test "Activate the Solenoid (SLT)" is performed, ECM commands SLT solenoid to turn OFF)
  • ON: No action (normal operation)

[Vehicle Condition]

  • Vehicle stopped
  • Engine idling

HINT:

*: Activate the Solenoid (SLT) in the Active Test is performed to check the line pressure changes by connecting SST to the automatic transmission, which is used in the Hydraulic Test AB60E AUTOMATIC TRANSMISSION / TRANSAXLE: AUTOMATIC TRANSMISSION SYSTEM: HYDRAULIC TEST (2008 Sequoia) as well. Please note that the pressure values in the Active Test and Hydraulic Test are different.

OK:

The line pressure changes as specified when performing the Active Test.

OK

3.

INSPECT SHIFT SOLENOID VALVE S4

(a) Remove the shift solenoid valve S4.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Shift solenoid valve S4 connector terminal - Shift solenoid valve S4 body

20°C (68°F)

11 to 15 Ω

(c) Connect the battery positive (+) lead to the terminal of the solenoid valve connector, and the negative (-) lead to the solenoid valve body. Then check that the valve moves and makes an operating noise.

OK:

Valve moves and makes an operating noise.

OK

4.

INSPECT SHIFT SOLENOID VALVE SL2

(a) Remove the shift solenoid valve SL2.

(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

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

OK:

Valve moves and makes an operating noise.

OK

5.

INSPECT TRANSMISSION VALVE BODY ASSEMBLY

(a) Check the transmission valve body assembly.

OK:

There are no foreign objects on each valve.

OK