SYSTEM DESCRIPTION
The ECM 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 ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical problems of the shift solenoid valves and valve body.
DTC No. | DTC Detection Condition | Trouble Area |
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P0776 | The engine revs freely when 4th, 5th, or 6th gear is commanded (2-trip detection logic). When any of the following is detected twice (2-trip detection logic):
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MONITOR DESCRIPTION
The ECM 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 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.
INSPECTION PROCEDURE
PROCEDURE
CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0776)
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the intelligent tester on.
Enter the following menus: Powertrain / Engine and ECT / DTC.
Read the DTCs using the intelligent tester.
Result | ||||||
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Tech Tips
If a solenoid is stuck OFF, DTCs for several solenoids including the malfunctioning solenoid will be detected.
A |
INSPECT SHIFT SOLENOID VALVE SL2 Click here |
B |
PERFORM ACTIVE TEST USING INTELLIGENT TESTER
Note
This test should always be performed with at least 2 people.
Warm up the engine.
Turn the ignition switch off.
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the intelligent tester on.
Enter the following menus: Powertrain / Engine and ECT / Active Test.
According to the display on the intelligent tester, perform the Active Test.
Tech Tips
Comparing the gear commanded by the Active Test with the actual gear enables confirmation of the problem Click here.
Tester Display | Test Details | Control Range | Diagnostic Note |
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Control the Shift Position | Operates the shift solenoid valves to allow gears to selected manually. |
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Can be used to check the operation of the shift solenoid valves. Upshifts and downshifts should be performed consecutively. A 10-second interval is required between gear changes. Do not downshift at high speeds. Doing so will damage the automatic transaxle. [Vehicle Condition] 50 km/h (31 mph) or less |
Note
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.
Tech Tips
The gear commanded by the ECM is shown in the Data List / Shift Status display on the intelligent tester.
Check the vehicle speed and the gear when the engine speed is 1000 rpm.
Tech Tips
Because the torque converter 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 | ||||||||||||
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Compare the ECM commanded gear and the actual gear.
Result | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Tech Tips
*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.
A |
GO TO DTC CHART (RELATED SHIFT SOLENOID VALVE (SL1) PERFORMANCE DTC P0746) Click here |
C |
GO TO DTC CHART (RELATED SHIFT SOLENOID VALVE (SL3) PERFORMANCE DTC P0796) Click here |
D |
GO TO DTC CHART (RELATED SHIFT SOLENOID VALVE (SL4) PERFORMANCE DTC P2808) Click here |
E |
GO TO DTC CHART (RELATED SHIFT SOLENOID VALVE (SLT) PERFORMANCE DTC P2714) Click here |
B |
INSPECT SHIFT SOLENOID VALVE SL2
*1 | Shift Solenoid Valve SL2 |
Remove shift solenoid valve SL2.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||
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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 |
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Valve moves and makes an operating sound. |
NG |
REPLACE SHIFT SOLENOID VALVE SL2 Click here |
OK |
INSPECT TRANSMISSION VALVE BODY ASSEMBLY
Check the transmission valve body assembly Click here.
OK |
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There are no foreign objects on each valve and they operate smoothly. |
NG |
REPLACE TRANSMISSION VALVE BODY ASSEMBLY Click here |
OK |
REPLACE AUTOMATIC TRANSAXLE ASSEMBLY Click here