| Last Modified: 11-29-2007 | 1.6 U | |
| Service Category: Drivetrain | Section: Automatic Transmission/Transaxle | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM000000O8L08SX |
| Title: A750E AUTOMATIC TRANSMISSION / TRANSAXLE: AUTOMATIC TRANSMISSION SYSTEM: FAIL-SAFE CHART (2008 Sequoia) | ||
FAIL-SAFE CHART
1. FAIL-SAFE
This function minimizes the loss of the ECT functions when a malfunction occurs in each sensor or solenoid.
|
Malfunction Part |
Function |
|---|---|
|
No. 1 ATF temperature sensor |
During a No. 1 ATF temperature sensor malfunction, up-shift to 5th gear and flex lock-up clutch control are prohibited. |
|
Speed sensor SP2 |
During an output speed sensor malfunction, shift control is performed through the input speed sensor NT signal. |
|
Shift solenoid valve S1, S2 and SR |
The current to the failed solenoid valve is cut off and control is performed by operating the other solenoid valves with normal operation. Shift control is performed depending on the failed solenoid as described in the table below. |
|
Shift solenoid valve SL1 and SL2 |
During a solenoid valve SL1 or SL2 malfunction, up-shift to 5th gear is prohibited. |
|
Shift solenoid valve SLT |
During a solenoid valve SLT malfunction, the current to the solenoid valve is stopped. This stops line pressure optimal control, and shift shock increases. However, shifting is performed through normal clutch pressure control. |
|
Shift solenoid valve SLU |
During a solenoid valve SLU malfunction, the current to the solenoid valve is stopped. This stops lock-up control and flex lock-up control, and fuel economy decreases. |
Shift Solenoid Valve Normal Operation Chart
|
Shift Lever Position |
Gear |
Shift Solenoid S1 |
Shift Solenoid S2 |
Shift Solenoid SR |
Shift Solenoid SL1 |
Shift Solenoid SL2 |
|---|---|---|---|---|---|---|
|
D S5 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
2nd |
ON |
ON |
OFF |
OFF |
ON |
|
|
3rd |
OFF |
ON |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
5th |
OFF |
OFF |
ON |
ON |
OFF |
|
|
S4 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
2nd |
ON |
ON |
OFF |
OFF |
ON |
|
|
3rd |
OFF |
ON |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
S3 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
2nd |
ON |
ON |
OFF |
OFF |
ON |
|
|
3rd E/B |
OFF |
ON |
OFF |
OFF |
OFF |
|
|
S2 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
2nd E/B |
ON |
ON |
ON |
OFF |
OFF |
|
|
S1 |
1st E/B |
ON |
OFF |
OFF |
OFF |
OFF |
2. FAIL-SAFE FUNCTION
If either of the shift solenoid valve circuits has an open or short failure, the ECM turns the other shift solenoid ON and OFF in order to shift into the gear positions shown in the table below.
In case of a short circuit, the ECM stops sending current to the short circuit solenoid.
Even if starting the engine again in the fail-safe mode, the gear position remains in the same position.
HINT:
- Electrical malfunction: Condition is shown above the "↓".
- Fail-safe mode: Condition is shown below the "↓".
- E/B: Engine brake.
Fail-Safe Operation When Shift Solenoid Valve S1 is Malfunctioning
|
Shift Lever Position |
Gear |
Shift Solenoid S1 |
Shift Solenoid S2 |
Shift Solenoid SR |
Shift Solenoid SL1 |
Shift Solenoid SL2 |
|---|---|---|---|---|---|---|
|
D S5 |
4th ↓ 3rd |
OFF |
OFF ↓ ON |
OFF |
OFF |
ON |
|
3rd |
OFF |
ON |
OFF |
OFF |
ON |
|
|
3rd |
OFF |
ON |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
5th |
OFF |
OFF |
ON |
ON |
OFF |
|
|
S4 |
4th ↓ 3rd |
OFF |
OFF ↓ ON |
OFF |
OFF |
ON |
|
3rd |
OFF |
ON |
OFF |
OFF |
ON |
|
|
3rd |
OFF |
ON |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
S3 |
3rd ↓ 3rd E/B |
OFF |
OFF ↓ ON |
OFF |
OFF |
ON ↓ OFF |
|
3rd ↓ 3rd E/B |
OFF |
ON |
OFF |
OFF |
ON ↓ OFF |
|
|
3rd E/B |
OFF |
ON |
OFF |
OFF |
OFF |
|
|
S2 |
1st |
OFF |
OFF |
OFF |
OFF |
ON |
|
3rd E/B |
OFF |
ON |
ON ↓ OFF |
OFF |
OFF |
|
|
S1 |
1st E/B |
OFF |
OFF |
OFF |
OFF |
OFF |
Fail-Safe Operation When Shift Solenoid Valve S2 is Malfunctioning
|
Shift Lever Position |
Gear |
Shift Solenoid S1 |
Shift Solenoid S2 |
Shift Solenoid SR |
Shift Solenoid SL1 |
Shift Solenoid SL2 |
|---|---|---|---|---|---|---|
|
D S5 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
1st ↓ 4th |
ON ↓ OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
5th |
OFF |
OFF |
ON |
ON |
OFF |
|
|
S4 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
1st ↓ 4th |
ON ↓ OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
S3 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
1st ↓ 3rd E/B |
ON ↓ OFF |
OFF |
OFF |
OFF |
ON ↓ OFF |
|
|
3rd E/B |
OFF |
OFF |
OFF |
OFF |
OFF |
|
|
S2 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
2nd E/B ↓ 4th |
ON ↓ OFF |
OFF |
ON ↓ OFF |
OFF |
OFF ↓ ON |
|
|
S1 |
1st E/B |
ON |
OFF |
OFF |
OFF |
OFF |
Fail-Safe Operation When Shift Solenoid Valve SR is Malfunctioning
|
Shift Lever Position |
Gear |
Shift Solenoid S1 |
Shift Solenoid S2 |
Shift Solenoid SR |
Shift Solenoid SL1 |
Shift Solenoid SL2 |
|---|---|---|---|---|---|---|
|
D S5 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
2nd |
ON |
ON |
OFF |
OFF |
ON |
|
|
3rd |
OFF |
ON |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
ON ↓ OFF |
OFF ↓ ON |
|
|
S4 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
2nd |
ON |
ON |
OFF |
OFF |
ON |
|
|
3rd |
OFF |
ON |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
S3 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
2nd |
ON |
ON |
OFF |
OFF |
ON |
|
|
3rd E/B ↓ 3rd |
OFF |
ON |
OFF |
OFF |
OFF |
|
|
S2 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
2nd |
ON |
ON |
OFF |
OFF |
OFF |
|
|
S1 |
1st E/B |
ON |
OFF |
OFF |
OFF |
OFF |
Fail-Safe Operation When Shift Solenoid Valve S1 and S2 are Malfunctioning
|
Shift Lever Position |
Gear |
Shift Solenoid S1 |
Shift Solenoid S2 |
Shift Solenoid SR |
Shift Solenoid SL1 |
Shift Solenoid SL2 |
|---|---|---|---|---|---|---|
|
D S5 |
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
5th |
OFF |
OFF |
ON |
ON |
OFF |
|
|
S4 |
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
S3 |
3rd ↓ 3rd E/B |
OFF |
OFF |
OFF |
OFF |
ON ↓ OFF |
|
3rd ↓ 3rd E/B |
OFF |
OFF |
OFF |
OFF |
ON ↓ OFF |
|
|
3rd E/B |
OFF |
OFF |
OFF |
OFF |
OFF |
|
|
S2 |
1st |
OFF |
OFF |
OFF |
OFF |
ON |
|
Fail 4th |
OFF |
OFF |
ON ↓ OFF |
OFF |
OFF ↓ ON |
|
|
S1 |
1st E/B |
OFF |
OFF |
OFF |
OFF |
OFF |
Fail-Safe Operation When Shift Solenoid Valve S2 and SR are Malfunctioning
|
Shift Lever Position |
Gear |
Shift Solenoid S1 |
Shift Solenoid S2 |
Shift Solenoid SR |
Shift Solenoid SL1 |
Shift Solenoid SL2 |
|---|---|---|---|---|---|---|
|
D S5 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
1st ↓ 4th |
ON ↓ OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
ON ↓ OFF |
OFF ↓ ON |
|
|
S4 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
1st ↓ 4th |
ON ↓ OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
S3 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
1st ↓ 3rd E/B |
ON ↓ OFF |
OFF |
OFF |
OFF |
ON ↓ OFF |
|
|
3rd E/B |
OFF |
OFF |
OFF |
OFF |
OFF |
|
|
S2 |
1st |
ON |
OFF |
OFF |
OFF |
ON |
|
1st E/B ↓ 1st |
ON |
OFF |
OFF |
OFF |
OFF ↓ ON |
|
|
S1 |
1st E/B |
ON |
OFF |
OFF |
OFF |
OFF |
Fail-Safe Operation When Shift Solenoid Valve S1 and SR are Malfunctioning
|
Shift Lever Position |
Gear |
Shift Solenoid S1 |
Shift Solenoid S2 |
Shift Solenoid SR |
Shift Solenoid SL1 |
Shift Solenoid SL2 |
|---|---|---|---|---|---|---|
|
D S5 |
4th ↓ 3rd |
OFF |
OFF ↓ ON |
OFF |
OFF |
ON |
|
3rd |
OFF |
ON |
OFF |
OFF |
ON |
|
|
3rd |
OFF |
ON |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
ON ↓ OFF |
OFF ↓ ON |
|
|
S4 |
4th ↓ 3rd |
OFF |
OFF ↓ ON |
OFF |
OFF |
ON |
|
3rd |
OFF |
ON |
OFF |
OFF |
ON |
|
|
3rd |
OFF |
ON |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
S3 |
3rd ↓ 3rd E/B |
OFF |
OFF ↓ ON |
OFF |
OFF |
ON ↓ OFF |
|
3rd ↓ 3rd E/B |
OFF |
ON |
OFF |
OFF |
ON ↓ OFF |
|
|
3rd E/B |
OFF |
ON |
OFF |
OFF |
OFF |
|
|
S2 |
1st |
OFF |
OFF |
OFF |
OFF |
ON |
|
2nd E/B |
OFF |
ON |
OFF |
OFF |
OFF |
|
|
S1 |
1st E/B |
OFF |
OFF |
OFF |
OFF |
OFF |
Fail-Safe Operation When Shift Solenoid Valve S1, S2 and SR are Malfunctioning
|
Shift Lever Position |
Gear |
Shift Solenoid S1 |
Shift Solenoid S2 |
Shift Solenoid SR |
Shift Solenoid SL1 |
Shift Solenoid SL2 |
|---|---|---|---|---|---|---|
|
D S5 |
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
ON ↓ OFF |
OFF ↓ ON |
|
|
S4 |
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
4th |
OFF |
OFF |
OFF |
OFF |
ON |
|
|
S3 |
3rd ↓ 3rd E/B |
OFF |
OFF |
OFF |
OFF |
ON ↓ OFF |
|
3rd ↓ 3rd E/B |
OFF |
OFF |
OFF |
OFF |
ON ↓ OFF |
|
|
3rd E/B |
OFF |
OFF |
OFF |
OFF |
OFF |
|
|
S2 |
1st |
OFF |
OFF |
OFF |
OFF |
ON |
|
1st E/B ↓ 1st |
OFF |
OFF |
OFF |
OFF |
OFF ↓ ON |
|
|
S1 |
1st E/B |
OFF |
OFF |
OFF |
OFF |
OFF |
|
|