A760E Automatic Transmission
A760E AUTOMATIC TRANSMISSION: ELECTRONIC CONTROLLED AUTOMATIC TRANSMISSION SYSTEM: P0766: Shift Solenoid "D" Performance (Shift Solenoid Valve S4)
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.).
HINT:
- Gear positions in the event of a solenoid valve mechanical problem:
- 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.
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 DTC.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
ALL
P0766 OFF malfunction (A) and P0776 ON malfunction (A)
P0766 OFF malfunction (B) and P0776 ON malfunction (B)
TYPICAL MALFUNCTION THRESHOLDS
[OFF malfunction]
- Both of the following conditions are met: OFF malfunction (A) and (B)
P0766 OFF malfunction (A)
P0766 OFF malfunction (B)
[ON malfunction]
- Both of the following conditions are met: ON malfunction (A) and (B)
P0776 ON malfunction (A)
P0776 ON malfunction (B)
INSPECTION PROCEDURE
1. ACTIVE 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 / Engine and 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.
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.
- The shift solenoid valve S4 and SL2 are turned ON/OFF normally when the shift lever is on D:
PROCEDURE
1. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0766 AND P0776)
(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 / Engine and ECT / Trouble Codes.
(d) Read the DTCs using the Techstream.
Result:
HINT:
If any other codes besides P0766 and P0776 are output, perform troubleshooting for those DTCs first.
B -- Go to DTC Chart Diagnostic Trouble Code Descriptions
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 / Engine and 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 -- REPLACE SHIFT SOLENOID VALVE SLT
OK -- Continue to next step.
3. INSPECT SHIFT SOLENOID VALVE S4
(a) Remove the shift solenoid valve S4.
(b) Measure the resistance of the solenoid valve.
Standard resistance:
(c) Connect the battery's positive (+) lead to the terminal of the solenoid valve connector, and the negative (-) lead to the solenoid body. Then check that the valve moves and makes an operating noise.
OK:
Valve moves and makes operating noise.
NG -- REPLACE SHIFT SOLENOID VALVE S4
OK -- Continue to next step.
4. INSPECT SHIFT SOLENOID VALVE SL2
(a) Remove the shift solenoid valve SL2.
(b) Measure the resistance of the solenoid valve.
Standard resistance:
(c) Connect the battery's positive (+) lead with a 21 W bulb to terminal 2 and the negative (-) lead to terminal 1 of the solenoid valve connector. Then check that the valve moves and makes an operating noise.
OK:
Valve moves and makes operating noise.
NG -- REPLACE SHIFT SOLENOID VALVE SL2
OK -- Continue to next step.
5. INSPECT TRANSMISSION VALVE BODY ASSEMBLY
(a) Check the transmission valve body assembly.
OK:
There are no foreign objects on each valve.
NG -- REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY
OK -- REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSEMBLY