P0751
A761E AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: P0751: Shift Solenoid "A" Performance (Shift Solenoid Valve S1)
DTC P0751 - Shift Solenoid "A" Performance (Shift Solenoid Valve S1)
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, gear, etc.).
HINT:
- Gear positions in the event of a solenoid valve mechanical problem:
N*: Neutral
- 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.
*3: Under engine braking, downshifting to 1st or 2nd gear is prohibited.
MONITOR DESCRIPTION
This DTC indicates "stuck ON malfunction" or "stuck OFF malfunction" of the shift solenoid valve S1.
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
OFF malfunction (A)
OFF malfunction (B)
OFF malfunction (C)
OFF malfunction (D)
ON malfunction (A)
ON malfunction (B)
TYPICAL MALFUNCTION THRESHOLDS
[OFF malfunction]
- Both of the following conditions are met: OFF malfunction (A) and OFF malfunction (B), (C) or (D)
OFF malfunction (A)
OFF malfunction (B)
OFF malfunction (C)
OFF malfunction (D)
[ON malfunction]
- Both of the following conditions are met: ON malfunction (A) and (B)
- 2 detections are necessary per driving cycle:
- 1st detection: temporary flag ON
- 2nd detection: pending fault code ON
ON malfunction (A)
ON malfunction (B)
INSPECTION PROCEDURE
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.
1 Connect the Techstream to the DLC3.
2 Turn the ignition switch to ON.
3 Turn the Techstream on.
4 Enter the following menus: Powertrain / Engine and ECT / Active Test.
5 According to the display on the Techstream, perform the Active Test.
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 -> 5th and 5th -> 6th up-shifts must be performed with the accelerator pedal released.
- The 6th -> 5th and 5th -> 4th down-shifts 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 valve S1 is turned ON/OFF normally when the shift lever is on D:
PROCEDURE
1. CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0751)
(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 P0751 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: 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) 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) According to the display on the Techstream, perform the Active Test.
(h) Measure the line pressure with SST.
Engine and ECT
HINT:
- *: Control the Line Pressure Up 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 S1
(a) Remove the shift solenoid valve S1.
(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 S1
OK -- Continue to next step.
4. INSPECT TRANSMISSION VALVE BODY ASSEMBLY
(a) Check the transmission valve body assembly Disassembly.
OK:
There are no foreign objects on any valve.
NG -- REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY
OK -- REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSEMBLY