Electronic Controlled Automatic Transmission System Fail-Safe Chart

Transmission. Lexus Gs430, Gs300. Uzs190 Grs190
A760E Automatic Transmission. Lexus Gs430, Gs300. Uzs190 Grs190

  1. FAIL-SAFE CHART

Electronic Controlled Automatic Transmission System -- Fail-Safe Chart



FAIL-SAFE CHART
This function minimizes the loss of the ECT functions when any malfunction occurs in each sensor or solenoid.
*1: AI (Artificial Intelligence) -SHIFT control
In addition to the switching of the shift pattern through the pattern select switch, the AI-SHIFT control enables the ECM to estimate the road conditions and the driver's intention in order to automatically select the optimal shift pattern. As a result, a comfortable ride has been realized.

Malfunction Part
Function
DTC P0717:
Input Speed Sensor (NT)
During an input speed sensor malfunction, shift control is effected through the output speed sensor signal (SP2).
During an input speed sensor malfunction, up-shift to the 5th and 6th, AI-SHIFT*1 and flex lock-up clutch control are prohibited.
DTC P0500:
Output Speed Sensor (SP2)
During an output speed sensor malfunction, shift control is effected through the input speed sensor signal (NT).
During an output speed sensor malfunction, up-shift to the 5th and 6th, AI-SHIFT*1 and flex lock-up clutch control are prohibited.
DTC P0710, P0712, P0713:
ATF Temp. Sensor
During an ATF temperature sensor malfunction, up-shift to the 5th and 6th and flex lock-up clutch control are prohibited.
Shift Solenoid Valve S1, S2, S3, S4 and SR
The current to the failed solenoid valve is cut off and control is effected by operating the other solenoid valves.
Shift control is effected depending on the failed solenoid as described in the table on the next page.
DTC P0748, P0778:
Shift Solenoid Valve SL1 and SL2
During a solenoid valve SL1 or SL2 malfunction, up-shift to the 5th and 6th and flex lock-up clutch control are prohibited.
DTC P2757, P2759:
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, fuel economy decreases.
DTC P02714, P2716:
Shift Solenoid Valve SLT
During a solenoid valve SLT malfunction, the current to the solenoid valve is stopped. This stops line pressure optimal control, the shift shock increases. However, shifting is effected through normal clutch pressure control.

  1. Fail-safe operation for electronically malfunctioning shift solenoid valve (S1, S2, S3, S4 and SR):

    HINT:
    Fail-safe operation in the event of an electric system malfunction.
    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 circuited solenoid.
    Even if staring the engine again in the fail-safe mode, the gear position remains in the same position.

    Fail-safe chart for electrical malfunction:
    Shift Lever Position
    		Normal
    Gear
    		Shift solenoid (ECM output)
    S1
    		S2
    		S3
    		S4
    		SR
    		SL1
    		SL2
    D,S6
    		1st
    		OFF
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    2nd
    		ON
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    3rd
    		ON
    		OFF
    		ON
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		OFF
    		OFF
    		ON
    		OFF
    		ON
    5th
    		ON
    		OFF
    		OFF
    		ON
    		OFF
    		ON
    		OFF
    6th
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    		OFF
    S5
    		1st
    		OFF
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    2nd
    		ON
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    3rd
    		ON
    		OFF
    		ON
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		OFF
    		OFF
    		ON
    		OFF
    		ON
    5th
    		ON
    		OFF
    		OFF
    		ON
    		OFF
    		ON
    		OFF
    S4
    		1st
    		OFF
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    2nd
    		ON
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    3rd
    		ON
    		OFF
    		ON
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		OFF
    		OFF
    		ON
    		OFF
    		ON
    S3
    		1st
    		OFF
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    2nd
    		ON
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    3rd (E/B)
    		ON
    		OFF
    		ON
    		OFF
    		ON
    		OFF
    		OFF
    S2
    		1st
    		OFF
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    2nd (E/B)
    		ON
    		ON
    		ON
    		ON
    		OFF
    		OFF
    		OFF
    S1
    		1st (E/B)
    		OFF
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		OFF

    Shift Lever Position
    		Shift Solenoid Valve S1 Electrical Malfunction (P0973, P0974)
    Gear*2
    		Shift solenoid (ECM output)
    S1
    		S2
    		S3
    		S4
    		SR
    		SL1
    		SL2
    D,S6
    		1st
    		X
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    1st→4th
    		X
    		ON→OFF
    		ON→OFF
    		OFF
    		ON
    		OFF
    		ON
    3rd→4th
    		X
    		OFF
    		ON→OFF
    		OFF
    		ON
    		OFF
    		ON
    4th
    		X
    		OFF
    		OFF
    		OFF
    		ON
    		OFF
    		ON
    5th
    		X
    		OFF
    		OFF
    		ON
    		OFF
    		ON
    		OFF
    N→5th
    		X
    		ON→OFF
    		OFF
    		ON
    		OFF
    		ON
    		OFF
    S5
    		1st
    		X
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    1st→4th
    		X
    		ON→OFF
    		ON→OFF
    		OFF
    		ON
    		OFF
    		ON
    3rd→4th
    		X
    		OFF
    		ON→OFF
    		OFF
    		ON
    		OFF
    		ON
    4th
    		X
    		OFF
    		OFF
    		OFF
    		ON
    		OFF
    		ON
    5th
    		X
    		OFF
    		OFF
    		ON
    		OFF
    		ON
    		OFF
    S4
    		1st
    		X
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    1st→4th
    		X
    		ON→OFF
    		ON→OFF
    		OFF
    		ON
    		OFF
    		ON
    3rd→4th
    		X
    		OFF
    		ON→OFF
    		OFF
    		ON
    		OFF
    		ON
    4th
    		X
    		OFF
    		OFF
    		OFF
    		ON
    		OFF
    		ON
    S3
    		1st
    		X
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    1st→4th
    		X
    		ON→OFF
    		ON→OFF
    		OFF
    		ON
    		OFF
    		ON
    3rd (E/B)→4th
    		X
    		OFF
    		ON→OFF
    		OFF
    		ON
    		OFF
    		OFF→ON
    S2
    		1st
    		X
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		ON
    1st (E/B)→4th
    		X
    		ON→OFF
    		ON→OFF
    		OFF
    		ON
    		OFF
    		OFF→ON
    S1
    		1st (E/B)
    		X
    		ON
    		ON
    		OFF
    		ON
    		OFF
    		OFF
    HINT:
    1. *2: Actual gear shift (gear position) under fail-safe operation.
    2. X: OFF (the ECM stops sending current to a malfunctioning solenoid valve)
    3. →: Condition in the electrical malfunction is shown on the left of "→".
      Condition in the fail-safe mode is shown on the right of "→".
    4. (E/B): Engine brake

    Shift Lever Position
    		Shift solenoid Valve S2 Electrical Malfunction (P0976, P0977)
    Gear*2
    		Shift solenoid (ECM output)
    S1
    		S2
    		S3
    		S4
    		SR
    		SL1
    		SL2
    D,S6
    		3rd
    		OFF→ON
    		X
    		ON
    		OFF
    		ON
    		OFF
    		ON
    3rd
    		ON
    		X
    		ON
    		OFF
    		ON
    		OFF
    		ON
    3rd
    		ON
    		X
    		ON
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		X
    		OFF
    		OFF
    		ON
    		OFF
    		ON
    5th
    		ON
    		X
    		OFF
    		ON
    		OFF
    		ON
    		OFF
    5th
    		ON
    		X
    		OFF
    		ON
    		OFF
    		ON
    		OFF
    S5
    		3rd
    		OFF→ON
    		X
    		ON
    		OFF
    		ON
    		OFF
    		ON
    3rd
    		ON
    		X
    		ON
    		OFF
    		ON
    		OFF
    		ON
    3rd
    		ON
    		X
    		ON
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		X
    		OFF
    		OFF
    		ON
    		OFF
    		ON
    5th
    		ON
    		X
    		OFF
    		ON
    		OFF
    		ON
    		OFF
    S4
    		3rd
    		OFF→ON
    		X
    		ON
    		OFF
    		ON
    		OFF
    		ON
    3rd
    		ON
    		X
    		ON
    		OFF
    		ON
    		OFF
    		ON
    3rd
    		ON
    		X
    		ON
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		X
    		OFF
    		OFF
    		ON
    		OFF
    		ON
    S3
    		3rd→3rd (E/B)
    		OFF→ON
    		X
    		ON
    		OFF
    		ON
    		ON→OFF
    		OFF
    3rd→3rd (E/B)
    		ON
    		X
    		ON
    		OFF
    		ON
    		ON→OFF
    		OFF
    3rd (E/B)
    		ON
    		X
    		ON
    		OFF
    		ON
    		OFF
    		OFF
    S2
    		3rd→3rd (E/B)
    		OFF→ON
    		X
    		ON
    		OFF
    		ON
    		ON→OFF
    		OFF
    3rd (E/B)
    		ON
    		X
    		ON
    		OFF
    		ON
    		OFF
    		OFF
    S1
    		3rd (E/B)
    		OFF→ON
    		X
    		ON
    		OFF
    		ON
    		OFF
    		OFF
    HINT:
    1. *2: Actual gear shift (gear position) under fail-safe operation.
    2. X: OFF (the ECM stops sending current to a malfunctioning solenoid valve)
    3. →: Condition in the electrical malfunction is shown on the left of "→".
      Condition in the fail-safe mode is shown on the right of "→".
    4. (E/B): Engine brake

    Shift Lever Position
    		Shift solenoid Valve S3 Electrical Malfunction (P0979, P0980)
    Gear*2
    		Shift solenoid (ECM output)
    S1
    		S2
    		S3
    		S4
    		SR
    		SL1
    		SL2
    D,S6
    		3rd→4th
    		OFF→ON
    		ON→OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		ON→OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    5th
    		ON
    		OFF
    		X
    		ON
    		OFF
    		ON
    		OFF
    6th
    		ON
    		ON
    		X
    		ON
    		OFF
    		ON
    		OFF
    S5
    		3rd→4th
    		OFF→ON
    		ON→OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		ON→OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    5th
    		ON
    		OFF
    		X
    		ON
    		OFF
    		ON
    		OFF
    S4
    		3rd→4th
    		OFF→ON
    		ON→OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		ON→OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    S3
    		3rd→4th
    		OFF→ON
    		ON→OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		ON→OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		X
    		OFF
    		ON
    		OFF
    		OFF→ON
    S2
    		3rd→4th
    		OFF→ON
    		ON→OFF
    		X
    		OFF
    		ON
    		OFF
    		ON
    6th→4th
    		ON
    		ON→OFF
    		X
    		OFF
    		ON
    		OFF
    		OFF→ON
    S1
    		1st (E/B)→4th
    		OFF→ON
    		ON→OFF
    		X
    		OFF
    		ON
    		OFF
    		OFF→ON
    HINT:
    1. *2: Actual gear shift (gear position) under fail-safe operation.
    2. X: OFF (the ECM stops sending current to a malfunctioning solenoid valve)
    3. →: Condition in the electrical malfunction is shown on the left of "→".
      Condition in the fail-safe mode is shown on the right of "→".
    4. (E/B): Engine brake

    Shift Lever Position
    		Shift Solenoid Valve S4 Electrical Malfunction (P0982, P0983)
    Gear*2
    		Shift solenoid (ECM output)
    S1
    		S2
    		S3
    		S4
    		SR
    		SL1
    		SL2
    D,S6
    		1st
    		OFF
    		ON
    		ON
    		X
    		ON
    		OFF
    		ON
    2nd
    		ON
    		ON
    		ON
    		X
    		ON
    		OFF
    		ON
    3rd
    		ON
    		OFF
    		ON
    		X
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		OFF
    		X
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		OFF
    		X
    		OFF→ON
    		ON→OFF
    		OFF→ON
    4th
    		ON
    		ON→OFF
    		OFF
    		X
    		OFF→ON
    		ON→OFF
    		OFF→ON
    S5
    		1st
    		OFF
    		ON
    		ON
    		X
    		ON
    		OFF
    		ON
    2nd
    		ON
    		ON
    		ON
    		X
    		ON
    		OFF
    		ON
    3rd
    		ON
    		OFF
    		ON
    		X
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		OFF
    		X
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		OFF
    		X
    		OFF→ON
    		ON→OFF
    		OFF→ON
    S4
    		1st
    		OFF
    		ON
    		ON
    		X
    		ON
    		OFF
    		ON
    2nd
    		ON
    		ON
    		ON
    		X
    		ON
    		OFF
    		ON
    3rd
    		ON
    		OFF
    		ON
    		X
    		ON
    		OFF
    		ON
    4th
    		ON
    		OFF
    		OFF
    		X
    		ON
    		OFF
    		ON
    S3
    		1st
    		OFF
    		ON
    		ON
    		X
    		ON
    		OFF
    		ON
    2nd
    		ON
    		ON
    		ON
    		X
    		ON
    		OFF
    		ON
    3rd (E/B)
    		ON
    		OFF
    		ON
    		X
    		ON
    		OFF
    		OFF
    S2
    		1st
    		OFF
    		ON
    		ON
    		X
    		ON
    		OFF
    		ON
    2nd (E/B)
    		ON
    		ON
    		ON
    		X
    		ON
    		OFF
    		OFF
    S1
    		1st (E/B)
    		OFF
    		ON
    		ON
    		X
    		ON
    		OFF
    		OFF
    HINT:
    1. *2: Actual gear shift (gear position) under fail-safe operation.
    2. X: OFF (the ECM stops sending current to a malfunctioning solenoid valve)
    3. →: Condition in the electrical malfunction is shown on the left of "→".
      Condition in the fail-safe mode is shown on the right of "→".
    4. (E/B): Engine brake

    Shift Lever Position
    		Shift Solenoid Valve SR Electrical Malfunction (P0985, P0986)
    Gear*2
    		Shift solenoid (ECM output)
    S1
    		S2
    		S3
    		S4
    		SR
    		SL1
    		SL2
    D,S6
    		1st
    		OFF
    		ON
    		ON
    		OFF
    		X
    		OFF
    		ON
    2nd
    		ON
    		ON
    		ON
    		OFF
    		X
    		OFF
    		ON
    3rd
    		ON
    		OFF
    		ON
    		OFF
    		X
    		OFF
    		ON
    4th
    		ON
    		OFF
    		OFF
    		OFF
    		X
    		OFF
    		ON
    5th
    		ON
    		OFF
    		OFF
    		ON
    		X
    		ON
    		OFF
    6th
    		ON
    		ON
    		OFF
    		ON
    		X
    		ON
    		OFF
    S5
    		1st
    		OFF
    		ON
    		ON
    		OFF
    		X
    		OFF
    		ON
    2nd
    		ON
    		ON
    		ON
    		OFF
    		X
    		OFF
    		ON
    3rd
    		ON
    		OFF
    		ON
    		OFF
    		X
    		OFF
    		ON
    4th
    		ON
    		OFF
    		OFF
    		OFF
    		X
    		OFF
    		ON
    5th
    		ON
    		OFF
    		OFF
    		ON
    		X
    		ON
    		OFF
    S4
    		1st
    		OFF
    		ON
    		ON
    		OFF
    		X
    		OFF
    		ON
    2nd
    		ON
    		ON
    		ON
    		OFF
    		X
    		OFF
    		ON
    3rd
    		ON
    		OFF
    		ON
    		OFF
    		X
    		OFF
    		ON
    4th
    		ON
    		OFF
    		OFF
    		OFF
    		X
    		OFF
    		ON
    S3
    		1st
    		OFF
    		ON
    		ON
    		OFF
    		X
    		OFF
    		ON
    2nd
    		ON
    		ON
    		ON
    		OFF
    		X
    		OFF
    		ON
    3rd
    		ON
    		OFF
    		ON
    		OFF
    		X
    		OFF
    		OFF
    S2
    		1st
    		OFF
    		ON
    		ON
    		OFF
    		X
    		OFF
    		ON
    2nd
    		ON
    		ON
    		ON
    		OFF
    		X
    		OFF
    		OFF
    S1
    		1st
    		OFF
    		ON
    		ON
    		OFF
    		X
    		OFF
    		OFF
    HINT:
    1. *2: Actual gear shift (gear position) under fail-safe operation.
    2. X: OFF (the ECM stops sending current to a malfunctioning solenoid valve)
    3. →: Condition in the electrical malfunction is shown on the left of "→".
      Condition in the fail-safe mode is shown on the right of "→".
    4. (E/B): Engine brake

  2. Fail-safe operation for mechanically malfunction:

    HINT:
    Fail-safe operation in the event of a mechanical system malfunction.
    Fail safe function:
    The ECM controls the gear position as shown in the table below when malfunctions occur.

    Fail-safe chart for mechanical malfunction:
    DTC
    		Condition
    		Gear*2
    -
    		Normal
    		1st
    		2nd
    		3rd
    		4th
    		5th
    		6th
    P0751
    		Shift solenoid valve S1:
    Stuck OFF malfunction
    		1st*3
    		1st*3
    		↑
    		3rd
    		3rd
    		3rd
    P0761
    		Shift solenoid S3:
    Stuck ON malfunction
    		1st
    		2nd
    		↑
    		3rd
    		3rd
    		3rd
    P0766
    		Shift solenoid valve S4, Shift solenoid valve SL2 or Valve body (Brake control valve):
    Malfunction
    		1st
    		2nd
    		↑
    		3rd
    		3rd
    		3rd
    P0781
    		Valve body (1-2 shift valve):
    Malfunction
    		1st*3
    		1st*3
    		↑
    		3rd
    		3rd
    		3rd
    P0729
    		Valve body (Reverse sequence valve):
    Malfunction
    		1st
    		2nd
    		↑
    		3rd
    		3rd
    		3rd
    HINT:
    *2: Actual gear shift (gear position) under fail-safe operation
    *3: Under engine braking, downshifting to 1st or 2nd gear is prohibited.