Toyota Tacoma (2015-2018) Service Manual: Pressure Control Solenoid "C" Performance (Shift Solenoid Valve SL3) (P0796)

Toyota Tacoma (2015-2018) Service Manual / Ac60e Automatic Transmission / Transaxle / Automatic Transmission System(for 2tr-fe) / Pressure Control Solenoid "C" Performance (Shift Solenoid Valve SL3) (P0796)

SYSTEM DESCRIPTION

The ECM uses the vehicle speed signal and signals from the transmission revolution sensors (NT, SP2) to detect the actual gear (1st, 2nd, 3rd, 4th, 5th or 6th gear).

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

DTC No.	DTC Detection Condition	Trouble Area
P0796	Either condition is met (2 trip detection logic): The engine revs freely when a shift to 2nd or 6th gear is commanded. The following condition is met twice: When a shift to 1st gear is commanded, 2nd gear is engaged.	Shift solenoid valve SL3 remains open or closed. Transmission valve body assembly is blocked. Automatic transmission assembly (clutch, brake or gear etc.)

MONITOR DESCRIPTION

The ECM commands gear shifts by turning the shift solenoid valves on and off. According to the input turbine speed and output shaft speed, the ECM detects the actual gear (1st, 2nd, 3rd, 4th, 5th or 6th gear). When the gear commanded by the ECM and the actual gear are not the same, the ECM illuminates the MIL and stores the DTC.

MONITOR STRATEGY

Related DTCs	P0796: Shift solenoid valve SL3/OFF malfunction Shift solenoid valve SL3/ON malfunction
Required sensors/Components	Shift solenoid valve SL3, Transmission revolution sensor (NT), Transmission revolution sensor (SP2), Crankshaft position sensor (NE)
Frequency of operation	Continuous
Duration	OFF malfunction (A) and (B): 0.5 sec. OFF malfunction (C) and (D): 0.8 sec. ON malfunction: 0.8 sec.
MIL operation	2 driving cycles
Sequence of operation	None

TYPICAL ENABLING CONDITIONS

All:

The monitor will run whenever the following DTCs are not stored	P0712, P0713 (TFT (ATF temperature) sensor circuit) P0115, P0117, P0118 (ECT (Engine coolant temperature) sensor circuit) P0717, P07BF, P07C0 (Turbine speed sensor circuit) P0722, P077C, P077D (Output speed sensor circuit) P0335 (Crankshaft position sensor circuit (This condition applies only if using fail-safe)) 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 (Knock control 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)
TFT (ATF temperature) sensor circuit	Not circuit malfunction
ECT (Engine coolant temperature) sensor circuit	Not circuit malfunction
Turbine speed sensor circuit	Not circuit malfunction
Output speed sensor circuit	Not circuit malfunction
Shift solenoid valve SL1 circuit	Not circuit malfunction
Shift solenoid valve SL2 circuit	Not circuit malfunction
Shift solenoid valve SL3 circuit	Not circuit malfunction
Shift solenoid valve SL4 circuit	Not circuit malfunction
KCS (Knock control sensor) circuit	Not circuit malfunction
ETCS (Electronic throttle control system)	Not system down
CAN communication system	Not system down
Transmission range	"D"
Duration time from shifting "N" to "D"	4 sec. or more
TFT (ATF temperature)	-10°C (14°F) or higher
Engine	Running

OFF malfunction (A):

ECM selected gear	2nd
Throttle valve opening angle	3% or more
ECM indicated pressure value of SL1	1600 kPa (16.3 kgf/cm2, 232 psi)
ECM indicated pressure value of SL2	0.1 kPa (0 kgf/cm2, 0 psi)
ECM indicated pressure value of SL3	1600 kPa (16.3 kgf/cm2, 232 psi)

OFF malfunction (B):

ECM selected gear	6th
Throttle valve opening angle	3% or more
ECM indicated pressure value of SL1	0.1 kPa (0 kgf/cm2, 0 psi)
ECM indicated pressure value of SL2	1600 kPa (16.3 kgf/cm2, 232 psi)
ECM indicated pressure value of SL3	1600 kPa (16.3 kgf/cm2, 232 psi)

OFF malfunction (C):

ECM selected gear	2nd
Vehicle speed	2 km/h (1.2 mph) or more
Throttle valve opening angle: (When condition "D" is not detected)	11.7% or more at engine speed 3000 rpm (Condition varies with engine speed)
Throttle valve opening angle: (When condition "D" is detected)	3% or more at output speed 900 rpm (Condition varies with output speed)
ECT (engine coolant temperature)	40°C (104°F) or higher

OFF malfunction (D):

Throttle valve opening angle

3% or more at output speed 900 rpm

(Condition varies with output speed)

ON malfunction:

ECM selected gear	1st
Vehicle speed	2 km/h (1.2 mph) to 40 km/h (24.9 mph)
Engine speed - Turbine speed	50 rpm or more
ECT (engine coolant temperature)	40°C (104°F) or higher

TYPICAL MALFUNCTION THRESHOLDS

[OFF malfunction]
- One of the following conditions is met: OFF malfunction (A), (B) or ((C) and (D))

OFF malfunction (A):

Turbine speed - Output speed x 2nd gear ratio

1000 rpm or more

OFF malfunction (B):

Turbine speed - Output speed x 6th gear ratio

1000 rpm or more

OFF malfunction (C) and (D):

Turbine speed / Output speed when output speed less than 1000 rpm

3.3500 to 7.3000

[ON malfunction]
- 2 detections are necessary per driving cycle:
- 1st detection: temporary flag ON
- 2nd detection: pending fault code ON

ON malfunction:

Turbine speed / Output speed when output speed less than 1000 rpm

1.9500 to 2.4000

CAUTION / NOTICE / HINT

NOTICE:

Perform the universal trip to clear permanent DTCs (See page ).
Perform registration and/or initialization when parts related to the automatic transmission are replaced (See page ).

HINT:

After the repair, clear the DTCs and perform the following procedure to check that DTCs are not output.

Perform the D Position Shift Test in Road Test (See page ).*1
Turn the ignition switch off.
Perform step (*1) again.
Check for DTCs again (See page ).

PROCEDURE

1.	CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0796)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

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

(e) Read the DTCs using the Techstream.

Result

Result	Proceed to
Only DTC P0796 is output	A
P0796 and other DTCs are output	B

HINT:

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

GO TO STEP 3

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.

(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:

Comparing the gear commanded by the Active Test with the actual gear enables confirmation of the problem (See page Engine and ECT ).

Engine and ECT

Tester Display	Test Part	Control Range	Diagnostic Note
Control the Shift Position	Operates the shift solenoid valves to allow gears to be selected manually.	Press "→" button: Up-shift occurs Press "←" button: Down-shift occurs	Can be used to check the operation of the shift solenoid valves. Up-shifts and down-shifts should be performed consecutively. A 10 second interval is required between gear changes. Do not down-shift at high speeds. Doing so will damage the automatic transmission. [Vehicle Condition] 50 km/h (31 mph) or less

Tester Display

Test Part

Control Range

Diagnostic Note

Control the Shift Position

Operates the shift solenoid valves to allow gears to be selected manually.

Press "→" button: Up-shift occurs
Press "←" button: Down-shift occurs

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

Up-shifts and down-shifts should be performed consecutively. A 10 second interval is required between gear changes.

Do not down-shift at high speeds. Doing so will damage the automatic transmission.

[Vehicle Condition]

50 km/h (31 mph) or less

HINT:

This test can be conducted when the vehicle speed is 50 km/h (31 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 gear commanded by the ECM is shown in the Data List / Shift Status display on the Techstream.

(h) Compare the ECM commanded gear and the actual gear.

Result

Actual Gear during Malfunction		ECM Commanded Gear						Proceed to
Actual Gear during Malfunction		1st	2nd	3rd	4th	5th	6th	Proceed to
Shift solenoid valve SL1	Stuck ON	1st	2nd	3rd	4th	4th	4th	A
Shift solenoid valve SL1	Stuck OFF	N*1	N*1	N*1	N*1	5th	6th	A
Shift solenoid valve SL2	Stuck ON	4th	4th	4th	4th	5th	6th	B
Shift solenoid valve SL2	Stuck OFF	1st	2nd	3rd	1st	N*1	N*1	B
Shift solenoid valve SL3	Stuck ON	2nd	2nd	3rd	4th	5th	6th	C
Shift solenoid valve SL3	Stuck OFF	1st	1st	3rd	4th	5th	N*1	C
Shift solenoid valve SL4	Stuck ON	3rd	3rd	3rd	4th	5th	5th	D
Shift solenoid valve SL4	Stuck OFF	1st	2nd	1st	4th	N*1	6th	D
Shift solenoid valve SLT	Stuck ON	N*2	N*2	N*2	N*2	N*2	N*2	E
Shift solenoid valve SLT	Stuck OFF*3	1st	2nd	3rd	4th	5th	6th	E

HINT:

*1: Neutral
*2: If shift solenoid valve 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 valve SLT is stuck off, gear shifting is normal.

GO TO DTC CHART (RELATED SHIFT SOLENOID VALVE SL1 PERFORMANCE DTC P0746)

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

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

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

3.	INSPECT SHIFT SOLENOID VALVE SL3

(a) Remove shift solenoid valve SL3 (See page ).

(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

OK:

Measurement Condition	Specified Condition
Battery positive (+) with a 21 W bulb → Terminal 1 Battery negative (-) → Terminal 2	Valve moves and makes an operating noise

Text in Illustration

*1	Shift Solenoid Valve SL3

REPLACE SHIFT SOLENOID VALVE SL3

4.	INSPECT TRANSMISSION VALVE BODY ASSEMBLY

(a) Check the transmission valve body assembly (See page OK: ).

OK:

There is no foreign matter on each valve and they operate smoothly.

REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSEMBLY

REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY

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