- Shift solenoid valve S1 remains open or closed
- Shift solenoid valve SLT remains open or closed
- Valve body is blocked
- Automatic transmission (clutch, brake or gear, etc.)
| Last Modified: 11-29-2007 | 1.6 C | |
| Service Category: Drivetrain | Section: Automatic Transmission/Transaxle | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM000000W8J045X |
| Title: A750E AUTOMATIC TRANSMISSION / TRANSAXLE: AUTOMATIC TRANSMISSION SYSTEM: DESCRIPTION (2008 Sequoia) | ||
|
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 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.).
|
DTC No. |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
P0751 |
Gear required by the ECM does not match the actual gear when driving. (2 trip detection logic) |
|
MONITOR DESCRIPTION
This DTC indicates a 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
|
Related DTCs |
P0751: Shift solenoid valve S1/OFF malfunction Shift solenoid valve S1/ON malfunction |
|
Required sensors/Components |
Shift solenoid valve S1, Vehicle sensor, Throttle position sensor, Speed sensor (NT), Speed sensor (SP2) |
|
Frequency of operation |
Continuous |
|
Duration |
OFF malfunction (A) and (B): 0.4 seconds OFF malfunction (C): Immediately ON malfunction (A), (B) and (C): 0.4 seconds ON malfunction (D): 3 seconds ON malfunction (E): 0.5 seconds |
|
MIL operation |
2 driving cycles |
|
Sequence of operation |
None |
TYPICAL ENABLING CONDITIONS
All
|
The monitor will run whenever the following DTCs are not present |
P0115 - P0118: ECT sensor P0125: Insufficient ECT for Closed Loop P0500: VSS P0748 - P0799: Trans solenoid (range) |
|
Turbine speed sensor circuit |
Not circuit malfunction |
|
Output speed sensor circuit |
Not circuit malfunction |
|
Shift solenoid valve S1 circuit |
Not circuit malfunction |
|
Shift solenoid valve S2 circuit |
Not circuit malfunction |
|
Shift solenoid valve SR circuit |
Not circuit malfunction |
|
Shift solenoid valve SL1 circuit |
Not circuit malfunction |
|
Shift solenoid valve SL2 circuit |
Not circuit malfunction |
|
ECT (Engine Coolant Temperature) sensor circuit |
Not circuit malfunction |
|
KCS sensor circuit |
Not circuit malfunction |
|
ETCS (Electric Throttle Control System) |
Not system down |
|
Transmission position |
"D" |
|
Duration time from shifting "N" to "D" |
4 seconds or more |
|
ECT |
40°C (104°F) or more |
|
Spark advance from max. retard timing by KCS control |
0°crankshaft angle or more |
|
Engine |
Starting |
OFF Malfunction (A)
|
ECM selected gear |
1st |
|
Vehicle speed |
2 km/h (1.2 mph) or more, and less than 40 km/h (24.9 mph) |
|
Throttle valve opening angle |
8% or more (when actual gear is 4th) 7% or more at 2000 rpm (Conditions vary with engine speed) |
OFF Malfunction (B)
|
Current ECM selected gear |
5th |
|
Last ECM selected gear |
4th |
|
Continuous time for ECM selecting 4th gear |
2 seconds or more |
|
Actual gear when ECM selected 4th gear |
4th |
OFF Malfunction (C)
|
Current ECM selected gear |
5th |
|
Last ECM selected gear |
4th |
ON Malfunction (A)
|
ECM selected gear |
1st |
|
Vehicle speed |
2 km/h (1.2 mph) or more, and less than 40 km/h (24.9 mph) |
|
Throttle valve opening angle |
8% or more (when actual gear is 4th) 7% or more at 2000 rpm (Conditions vary with engine speed) |
ON Malfunction (B)
|
ECM selected gear |
4th |
|
Vehicle speed |
2 km/h (1.2 mph) or more |
|
Throttle valve opening angle |
7% or more at 2000 rpm (Conditions vary with engine speed) |
ON Malfunction (C)
|
ECM selected gear |
3rd |
|
Vehicle speed |
2 km/h (1.2 mph) or more |
|
Throttle valve opening angle |
7% or more at 2000 rpm (Conditions vary with engine speed) |
ON Malfunction (D)
|
Current ECM selected gear |
5th |
|
Last ECM selected gear |
4th |
|
Vehicle speed (During transition from 4th to 5th gear) |
Less than 100 km/h (62.2 mph) |
ON Malfunction (E)
|
ECM selected gear |
5th |
|
Engine speed - Turbine speed (NE - NT) (After transition from 4th to 5th gear) |
150 rpm or less |
|
Vehicle speed (After transition from 4th to 5th gear) |
Less than 100 km/h (62.2 mph) |
TYPICAL MALFUNCTION THRESHOLDS
[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)
|
Turbine speed/Output speed (NT/NO) |
0.93 or more, and 1.07 or less (This means actual gear is 4th) |
OFF Malfunction (B)
|
Turbine speed/Output speed (NT/NO) |
0.65 or more, and 0.79 or less (This means actual gear is 5th) |
OFF Malfunction (C)
|
Output record of ECU from 4th to 5th up-shifting |
Recorded |
[ON malfunction]
Either of the following conditions is met:
ON malfunction (A) and (B)
ON malfunction (B) or (C), and ON malfunction (D) or (E)
ON Malfunction (A) and (B)
|
Turbine speed/Output speed (NT/NO) |
3.30 or more, and 7.50 or less (This means actual gear is 1st) |
ON Malfunction (C)
|
Turbine speed/Output speed (NT/NO) |
1.91 or more, and 2.35 or less (This means actual gear is 2nd) |
ON Malfunction (D)
|
Turbine speed - Output speed x 4th gear ratio (NT - NO x 4th gear ratio) |
1000 rpm or more |
ON Malfunction (E)
|
Turbine speed - Output speed x 5th gear ratio (NT - NO x 5th gear ratio) |
1000 rpm or more |
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 / ECT / Active Test.
(g) 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
.
ECT
|
Tester Display |
Test Part |
Control Range |
Diagnostic Note |
|---|---|---|---|
|
Control the Shift Position |
Operate shift solenoid valve and set each shift position by yourself |
|
Possible to check operation of shift solenoid valves [Vehicle Condition] 50 km/h (30 mph) or less |
HINT:
- This test can be conducted when the vehicle speed is 50 km/h (30 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 valve S1 turns ON/OFF normally when the shift lever is in D.
|
ECM gear shift command |
1st |
2nd |
3rd |
4th |
5th |
|
Shift solenoid valve S1 |
ON |
ON |
OFF |
OFF |
OFF |
PROCEDURE
|
1. |
CHECK DTC 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 / ECT / Trouble Codes.
(e) Read the DTCs using the Techstream.
Result
|
Result |
Proceed to |
|---|---|
|
Only P0751 is output |
A |
|
P0751 and other DTCs are output |
B |
HINT:
If any other codes besides P0751 are output, perform troubleshooting for those DTCs first.
|
|
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 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 / ECT / Active Test.
(g) According to the display on the Techstream, perform the Active Test.
(h) Measure the line pressure.
ECT
|
Tester Display |
Test Part |
Control Range |
Diagnostic Note |
|---|---|---|---|
|
Activate the Solenoid (SLT)* |
Operate the shift solenoid SLT and raise line pressure |
ON or OFF HINT:
|
[Vehicle Condition]
|
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
as well. Please note that the pressure values in the Active Test and Hydraulic Test are different.
OK:
The line pressure changes as specified when performing the Active Test.
|
|
3. |
INSPECT SHIFT SOLENOID VALVE S1 |
|
(a) Remove the shift solenoid valve S1. |
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
Shift solenoid valve S1 connector terminal - Shift solenoid valve S1 body |
20°C (68°F) |
11 to 15 Ω |
(c) Connect the battery positive (+) lead to the terminal of the solenoid valve connector, and the negative (-) lead to the solenoid valve body. Then check that the valve moves and makes an operating noise.
OK:
Valve moves and makes an operating noise.
|
|
4. |
INSPECT TRANSMISSION VALVE BODY ASSEMBLY |
(a) Check the transmission valve body assembly.
OK:
There are no foreign objects on each valve.
|
|
|