P0746
A750E AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: P0746,P0771: Pressure Control Solenoid "A" Performance (Shift Solenoid Valve SL1)
DTC P0746 - Pressure Control Solenoid "A" Performance (Shift Solenoid Valve SL1)
DTC P0771 - Shift Solenoid "E" Performance (Shift Solenoid Valve SR)
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 or 5th 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.).
MONITOR DESCRIPTION
These DTCs indicate a stuck ON malfunction or stuck OFF malfunction of the shift solenoid valves SR and SL1.
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 the same, the ECM illuminates the MIL and stores the DTC.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
All
P0746 and P0771: OFF Malfunction (A)
P0746 and P0771: OFF Malfunction (B)
P0746 and P0771: OFF Malfunction (C)
P0771: ON Malfunction
TYPICAL MALFUNCTION THRESHOLDS
[P0746 and P0771: OFF malfunction]
- All of the following conditions are met: OFF malfunction (A), (B) and (C)
2 detections are necessary per driving cycle
1st detection: temporary flag ON
2nd detection: pending fault code ON
OFF Malfunction (A)
OFF Malfunction (B)
OFF Malfunction (C)
[P0771: ON malfunction]
- 2 detections are necessary per driving cycle
1st detection: temporary flag ON
2nd detection: pending fault code ON
ON Malfunction
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) 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.
Engine and ECT
HINT:
- This test can be conducted when the vehicle speed is 50 km/h (31 mph) or less.
- The 4th to 5th up-shift must be performed with the accelerator pedal released.
- The 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 valves SR and SL1 turn ON/OFF normally when the shift lever is in D :
PROCEDURE
1. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0746 AND P0771)
(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
HINT: If any other codes besides P0746 and P0771 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)
NOTE:
- 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: 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) Turn the ignition switch off.
(b) Lift the vehicle up.
(c) Remove the test plug on the transmission case center right side and connect SST.
SST: 09992-00095
09992-00231
09992-00271
(d) Lower the vehicle.
(e) Fully apply the parking brake and chock the 4 wheels.
(f) Connect the Techstream to the DLC3.
(g) Start the engine and warm it up.
(h) Measure the line pressure when the engine is idling.
(i) Turn the Techstream on.
(j) Enter the following menus: Powertrain / Engine and ECT / Active Test.
(k) Follow the instructions on the Techstream and perform the Active Test.
(l) Measure the line pressure with SST.
Engine and ECT
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 Hydraulic Test as well. Please note that the pressure values in the Active Test and Hydraulic Test are different.
Result
C -- REPLACE SHIFT SOLENOID VALVE SLT
B -- INSPECT SHIFT SOLENOID VALVE SR
A -- Continue to next step.
3. INSPECT SHIFT SOLENOID VALVE SL1
(a) Remove the shift solenoid valve SL1.
(b) Measure the resistance according to the value(s) in the table below.
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:
The solenoid makes an operating sound.
NG -- REPLACE SHIFT SOLENOID VALVE SL1
OK -- Continue to next step.
4. INSPECT SHIFT SOLENOID VALVE SR
(a) Remove the shift solenoid valve SR.
(b) Measure the resistance according to the value(s) in the table below.
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:
The solenoid makes an operating sound.
NG -- REPLACE SHIFT SOLENOID VALVE SR
OK -- Continue to next step.
5. INSPECT TRANSMISSION VALVE BODY ASSEMBLY
(a) Check the transmission valve body assembly Installation.
OK:
There are no foreign objects on any valve.
NG -- REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY
OK -- REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSEMBLY