Drivetrain. Yaris. Ncp93, 131
U340E Automatic Transmission Transaxle. Yaris. Ncp93, 131
TYPICAL MALFUNCTION THRESHOLDS
CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0751)
INSPECT SHIFT SOLENOID VALVE S1
INSPECT TRANSMISSION VALVE BODY ASSEMBLY
DTC P0751 Shift Solenoid "A" Performance (Shift Solenoid Valve S1) |
DESCRIPTION
The ECM uses signals from the vehicle speed sensor and speed sensor NT to detect the actual gear position (1st, 2nd, 3rd or 4th).Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect the mechanical problems of the shift solenoid valves, the valve body or automatic transaxle (clutch, brake or gear etc.).
| DTC No. | DTC Detection Condition | Trouble Area |
| P0751 | S1 stuck OFF malfunction*1: ECM determines there is malfunction when both of following conditions are met (2 trip detection logic). (a) When ECM directs gearshift to switch to 1st gear, actual gear is shifted to 4th. (b) When ECM directs gearshift to switch to 4th gear, actual gear is shifted to 4th. |
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| S1 stuck ON malfunction*2: ECM determines that there is malfunction when both of following conditions are met (2 trip detection logic). (a) When ECM directs gearshift to switch from 3rd to 4th gear, actual gear is not shifted as above. (b) When ECM directs gearshift to switch to 4th gear, engine speed surges 1100 rpm or more. |
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- HINT:
- Gear positions in the event of a solenoid valve mechanical problem:
| Gearshift controlled by ECM | 1st | 2nd | 3rd | 4th |
| *1: Actual gear position under S1 stuck OFF malfunction | 4th | 3rd | 3rd | 4th |
| *2: Actual gear position under S1 stuck ON malfunction | 1st | 2nd | 2nd | 1st |
MONITOR DESCRIPTION
This DTC indicates "stuck ON malfunction" or "stuck OFF malfunction" of shift solenoid valve S1.The ECM controls the gearshifts by turning the shift solenoid valves ON/OFF. When the gear position directed by the ECM and the actual gear position do not match, 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, Speed sensor (NT), Speed sensor (SPD) |
| Frequency of operation | Continuous |
| Duration | OFF malfunction (a): 0.85 seconds OFF malfunction (b): 0.8 seconds ON malfunction (a): 0.8 seconds ON malfunction (b): 0.8 seconds |
| MIL operation | 2 driving cycle |
| Sequence of operation | None |
TYPICAL ENABLING CONDITIONS
The following conditions are common to all OFF malfunctions and ON malfunctions.| ECT (Engine Coolant Temperature) | 60°C (140°F) or more |
| Time after shifting N to D | 4.5 seconds or more |
| Transmission shift position | D |
| Shift Solenoid "A" (S1) circuit | No circuit malfunction (P0973, P0974) |
| Shift Solenoid "B" (S2) circuit | No circuit malfunction (P0976, P0977) |
| ECT sensor circuit | No circuit malfunction (P0115, P0117, P0118) |
| Turbine Speed Sensor circuit | No circuit malfunction (P0717) |
| Vehicle Speed Sensor "A" circuit | No circuit malfunction (P0500) |
| Electronic Throttle Control System | No circuit malfunction (P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0604, P0606, P0607*1, P060A, P060D, P060E, P0657, P1607, P2102, P2103, P2111, P2112, P2118, P2119, P2135) |
- *1: for Mexico models
| ECM gearshift command | 1st |
| Vehicle speed | 9 to 40 km/h (5.6 to 24.9 mph) |
| Throttle valve opening angle | 9% or more 7% or more at engine speed of 1900 rpm (Conditions vary with engine speed) |
| ECM gearshift command | 4th |
| Last ECM selected gear | 3rd |
| ECM gearshift command | 4th |
| Last ECM selected gear | 3rd |
| ECM gearshift command | 4th |
| V current - V last V current: Vehicle speed at current ECM selected gear V last: Vehicle speed at last ECM selected gear | Less than 15 km/h (9.3 mph) |
| TH current - TH last TH current: Throttle valve opening angle at current ECM selected gear TH last: Throttle valve opening angle at last ECM selected gear | Less than 30% |
| Vehicle speed (current) | Less than 85 km/h (52.8 mph) |
| Throttle valve opening angle (current) | Less than 45% |
| Engine speed (current) | 3200 rpm or more |
TYPICAL MALFUNCTION THRESHOLDS
[OFF malfunction]
- Both of the following conditions met: OFF malfunctions (a) and (b)
2 detections are necessary per driving cycle.
1st detection: Temporary flag ON
2nd detection: Pending fault code ON
| Input speed/Output speed (NT/NO) NT: Input (turbine) speed NO: Internal counter shaft speed | 0.64 to 0.78 |
| Input speed/Output speed (NT/NO) | Changes as follows 0.95 to 1.09 (Last) to 0.64 to 0.78 (Current) |
[ON malfunction]
- Both of the following conditions met: ON malfunctions (a) and (b)
| Input speed/Output speed (NT/NO) | Does not change as follows 0.95 to 1.09 (Last) to 0.64 to 0.78 (Current) |
NE change
| 1100 rpm or more |
INSPECTION PROCEDURE
- NOTICE:
- Perform the universal trip to clear permanent DTCs (YARIS_NCP93 RM000000W770OEX.html).
| 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.
Warm up the engine.
Turn the ignition switch off.
Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Active Test.
In accordance with the display on the Techstream, perform the Active Test.
- HINT:
- While driving, the shift position can be forcibly changed using the Techstream.
- Comparing the shift position commanded by the Active Test with the actual shift position enables you to confirm the problem (YARIS_NCP93 RM000000W7E0MUX.html).
Tester Display Test Part Control Range Diagnostic Note Control the Shift Position [Test Details]
Operate shift solenoid valve and set each shift position.
[Others]- Press "→" button: Shift up
- Press "←" button: Shift down
1st/2nd/3rd/4th Possible to check operation of shift solenoid valves.
[Vehicle Condition]- Vehicle speed: Less than 50 km/h (30 mph)
- HINT:
- This test can be conducted when the vehicle speed is 50 km/h (30 mph) or less.
- The 3rd to 4th up-shifting must be performed with the accelerator pedal released.
- The 4th to 3rd down-shifting 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 more than once in succession.
- The shift position commanded by the ECM is shown in the Data List/Shift Status display on the Techstream.
- Shift solenoid valve S1 is turned on/off normally when the shift lever is in the D position:
Gearshift controlled by ECM 1st 2nd 3rd 4th Shift solenoid valve S1 ON ON OFF OFF
| 1.CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P0751) |
Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
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 DTCs besides P0751 are output, perform troubleshooting for those DTCs first.
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| A | |
| 2.INSPECT SHIFT SOLENOID VALVE S1 |
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Remove shift solenoid valve S1.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition 1 - Solenoid Body 20°C (68°F) 11 to 15 Ω
Connect the positive (+) lead to the terminal of the solenoid connector and the negative (-) lead to the solenoid body to check the solenoid valve operation.
- OK:
- The solenoid makes operating sounds.
Text in Illustration *a Component without harness connected
(Shift Solenoid Valve S1)
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| OK | |
| 3.INSPECT TRANSMISSION VALVE BODY ASSEMBLY |
Check the transmission valve body assembly (YARIS_NCP93 RM00000192Z02PX.html).
- OK:
- There are no foreign objects on any valves and they operate smoothly.
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| OK | ||
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