Automatic Transmission - U760E
U760E AUTOMATIC TRANSMISSION / TRANSAXLE: AUTOMATIC TRANSAXLE SYSTEM: P0746: Pressure Control Solenoid "A" Performance (Shift Solenoid Valve SL1)
P0746 - Pressure Control Solenoid "A" Performance (Shift Solenoid Valve SL1)
SYSTEM DESCRIPTION
The TCM uses the vehicle speed signal and signals from the transmission speed sensors (NC, NT) to detect the actual gear (1st, 2nd, 3rd, 4th, 5th or 6th gear).
Then the TCM compares the actual gear with the shift schedule in the TCM memory to detect mechanical problems of the shift solenoid valves and valve body.
MONITOR DESCRIPTION
The TCM commands gear shifts by turning the shift solenoid valves on and off. According to the input shaft revolution (speed), intermediate (counter) shaft revolution (speed) and output shaft revolution (speed), the TCM detects the actual gear (1st, 2nd, 3rd, 4th, 5th or 6th gear). When the gear commanded by the TCM and the actual gear are not the same, the TCM illuminates the MIL and stores the DTC.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
ALL:
ALL::
OFF malfunction:
OFF malfunction::
ON malfunction:
ON malfunction::
TYPICAL MALFUNCTION THRESHOLDS
Either of the following conditions is met:
*
OFF malfunction:
OFF malfunction::
ON malfunction:
ON malfunction::
INSPECTION PROCEDURE
NOTICE:
Perform the universal trip to clear permanent DTCs .
PROCEDURE
1. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0746)
(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 / ECT / Trouble Codes.
(e) Read the DTCs using the Techstream.
Result:
HINT
If a solenoid is stuck OFF, DTCs for several solenoids including the malfunctioning solenoid will be detected.
A -- INSPECT SHIFT SOLENOID VALVE SL1
B -- Continue to next step.
2. PERFORM ACTIVE TEST USING TECHSTREAM
NOTICE:
This test should always be performed with at least 2 people.
(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 / 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 .
NOTICE:
- This test can be conducted when the vehicle is stopped.
- When shifting gears using the Active Test function, do not operate the accelerator pedal for 2 seconds before and after shifting gears.
HINT
The gear commanded by the TCM is shown in the Data List / Shift Status display on the Techstream.
(h) Check the vehicle speed and the gear when the engine speed is 1000 rpm.
HINT
Because the torque converter clutch has not engaged, it may be difficult to obtain the speeds specified in 4th, 5th, and 6th gear, however a difference of speed should still be evident following each gear change.
Standard:
(i) Compare the TCM commanded gear and the actual gear.
Result:
HINT
- *1: Neutral
- *2: If shift solenoid 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 SLT is stuck off, gear shifting is normal.
E -- GO TO DTC CHART (RELATED SHIFT SOLENOID VALVE (SLT) PERFORMANCE DTC P2714) P2714
D -- GO TO DTC CHART (RELATED SHIFT SOLENOID VALVE (SL4) PERFORMANCE DTC P2808) P2808
C -- GO TO DTC CHART (RELATED SHIFT SOLENOID VALVE (SL3) PERFORMANCE DTC P0796) P0796
B -- GO TO DTC CHART (RELATED SHIFT SOLENOID VALVE (SL2) PERFORMANCE DTC P0776) P0776
A -- Continue to next step.
3. INSPECT SHIFT SOLENOID VALVE SL1
(a) Remove shift solenoid valve SL1.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
(c) Connect a battery positive (+) lead with a 21 W bulb to terminal 2 and a negative (-) lead to terminal 1 of the solenoid valve connector. Then check that the valve moves and makes an operating sound.
OK:
Valve moves and makes an operating sound.
Text in Illustration
Text in Illustration:
NG -- REPLACE SHIFT SOLENOID VALVE SL1
OK -- Continue to next step.
4. INSPECT TRANSMISSION VALVE BODY ASSEMBLY
(a) Check the transmission valve body assembly .
OK:
There are no foreign objects on each valve and they operate smoothly.
NG -- REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY
OK -- REPAIR OR REPLACE AUTOMATIC TRANSAXLE ASSEMBLY