A760H Automatic Transmission

A760H AUTOMATIC TRANSMISSION: ELECTRONIC CONTROLLED AUTOMATIC TRANSMISSION SYSTEM: P0894,P2714: Transmission Component Slipping
P2714 - Pressure Control Solenoid "D" Performance (Shift Solenoid Valve SLT)

DESCRIPTION

The linear solenoid valve (SLT) controls the transmission line pressure for smooth transmission operation based on signals from the throttle position sensor and the vehicle speed sensor. The ECM adjusts the duty ratio* of the SLT solenoid valve to control hydraulic line pressure coming from the primary regulator valve. Appropriate line pressure assures smooth shifting with varying engine outputs.

HINT
*: The duty ratio is the ratio of the current ON time (A) to the total of the current ON and OFF time (A + B).

Duty Ratio (%) = A / (A + B) x 100

MONITOR DESCRIPTION

The ECM calculates the amount of heat absorbed by the friction material based on the difference in revolution (clutch slippage) between the turbine and output shaft. The ECM illuminates the MIL and outputs this DTC when the amount of heat absorption exceeds the specified value.

There are two reasons that make the revolution difference.

- When the shift solenoid valve SLT remains on, oil pressure goes down and clutch engagement force decreases.

- When the shift solenoid valve remains on or off, the gear position commanded by the ECM and the actual gear position are not the same.

NOTICE:
If you continue driving under these conditions, the clutch will burn out and the vehicle will no longer be drivable.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

ALL

TYPICAL MALFUNCTION THRESHOLDS

[P0894: ON malfunction]

- When either condition below is met: OFF malfunction (A) or (B)

ON malfunction (A)

ON malfunction (B)

[P2714: ON malfunction]

- One of the following conditions is met: ON malfunction (A), (B), (C), (D), (E), (F), (G) or (H)

ON malfunction (A)

ON malfunction (B)

ON malfunction (C)

ON malfunction (D)

ON malfunction (E)

ON malfunction (F)

ON malfunction (G)

ON malfunction (H)

INSPECTION PROCEDURE

NOTICE:
Perform the universal trip to clear permanent DTCs DTC Check / Clear.

PROCEDURE

1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0894 AND P2714)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG) and push the Techstream main switch ON.

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

(d) Read the DTCs using the Techstream.

Result:

HINT
If any other codes besides P0894 and P2714 are output, perform troubleshooting for those DTCs first.

B -- GO TO DTC CHART
A -- Continue to next step.

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's hose from interfering with the exhaust pipe.
- Perform the test with the A/C OFF.
HINT
Performing the Techstream Active Test allows relay, VSV, actuator and other items to be operated without removing any parts. Performing the Active Test early in troubleshooting is one way to save time. The Data List can be displayed during the Active Test.

(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 / ECT / Active Test.

(g) Follow the instructions on the tester and perform the Active Test.

(h) Measure the line pressure with SST.

ECM:

HINT
- *: Activate the Solenoid (SLT) in the Active Test is performed to check the line pressure change by connecting SST to the automatic transmission, which is used in the HYDRAULIC TEST Hydraulic Test.
- The pressure values in the Active Test and HYDRAULIC TEST are different from each other.
- Normally, the line pressure detected in the Active Test is approximately half of the value detected in the HYDRAULIC TEST's stall test.

OK:

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

NG -- INSPECT SHIFT SOLENOID VALVE SLT
OK -- Continue to next step.

3. PERFORM ACTIVE TEST USING TECHSTREAM (RUNNING TEST)

HINT
Performing the Techstream Active Test allows relay, VSV, actuator and other items to be operated without removing any parts. Performing the Active Test early in troubleshooting is one way to save time.

The Data List can be displayed during the Active Test.

(a) Warm up the engine.

(b) Turn the engine switch off.

(c) Connect the Techstream to the DLC3.

(d) Turn the engine switch on (IG).

(e) Turn the Techstream ON.

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

(g) Perform the Active Test using the Techstream.

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 Fail-Safe Chart.

ECM:

HINT
- This test can be conducted when the vehicle speed is 50 km/h (31 mph) or less.
- The 4th -> 5th and 5th -> 6th up-shiftings must be performed with the accelerator pedal released.
- The 6th -> 5th and 5th -> 4th down-shiftings 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 (Shift Status) display on the Techstream.
- Gear positions in the event of a solenoid valve mechanical problem:

HINT
- *1: When shift solenoid S1 is stuck ON, the vehicle cannot drive in reverse.
- *2: Neutral
- *3: When shift solenoid S4 is stuck ON, gear shifting is normal.

OK:

Gear position changes in accordance with the tester command.

D -- INSPECT SHIFT SOLENOID VALVE S4

C -- INSPECT SHIFT SOLENOID VALVE S3

B -- INSPECT SHIFT SOLENOID VALVE S2

OK -- INSPECT SHIFT SOLENOID VALVE SLT
A -- Continue to next step.

4. INSPECT SHIFT SOLENOID VALVE S1

(a) Remove the shift solenoid valve S1.