Fail-Safe Chart

This function minimizes the loss of the ECT functions when any malfunction occurs in a sensor or solenoid.

1. Vehicle speed signal (SPD): When there are problems with vehicle speed signals, O/D up shift is prohibited.
2. Speed sensor (NT): When the input turbine speed sensor has a malfunction, O/D up shift is prohibited.
3. Automatic Transmission Fluid (ATF) temperature sensor:

   When the ATF temperature sensor has a malfunction, O/D up shift is prohibited.

4. Shift solenoid valve SL:

   If the ECM detects a malfunction in the solenoid valve SL, it turns the valve OFF.

5. Shift solenoid valve SLT:

   When the solenoid valve SLT has a malfunction, O/D up shift is prohibited.

6. Engine Coolant Temperature (ECT) sensor:

   When the ECT sensor has a malfunction, O/D upshift is prohibited.

7. Knock sensor:

   When the knock sensor has a malfunction, O/D upshift is prohibited.

8. Throttle position sensor:

   When the throttle position sensor has a malfunction, O/D up shift is prohibited.

9. Shift solenoid valve S1 and S2:

   Fail-safe function:

   If either of the shift solenoid valve circuits develops an open or short, the ECM turns the other shift solenoid "ON" and "OFF" in order to shift into the gear positions shown in the table below.

   The ECM also turns the shift solenoid valve ST OFF at the same time. If both solenoids malfunction, hydraulic control cannot be performed electronically and must be done manually.

   Manual shifting as shown in the following table must be done. In case of a short circuit, the ECM stops sending the current to the short circuit solenoid.

   Even if starting the engine in the fail-safe mode, the gear position remains in the same position.

   FAIL-SAFE CHART
   
   

   Position	Normal			Shift Solenoid Valve S1 Malfunctioning			Shift Solenoid Valve S2 Malfunctioning			Both Solenoid Valves Malfunctioning
   	Solenoid Valve		Gear	Solenoid Valve		Gear	Solenoid Valve		Gear	Gear when shift selector is manually operated
   	S1	S2		S1	S2		S1	S2
   D	ON	ON	1st	X	ON then OFF	3rd	ON	X	2nd	3rd
   	ON	OFF	2nd	X	OFF	3rd	ON	X	2nd	3rd
   	OFF	OFF	3rd	X	OFF	3rd	OFF	X	3rd	3rd
   	OFF	ON	O/D	X	ON	O/D	OFF	X	3rd	3rd
   2	ON	ON	1st	X	ON then OFF	3rd	ON	X	2nd	3rd
   	ON	OFF	2nd	X	OFF	3rd	ON	X	2nd	3rd
   	OFF	OFF	3rd	X	OFF	3rd	OFF	X	3rd	3rd
   L	ON	ON	1st	X	ON then OFF	3rd	ON	X	2nd	3rd
   	ON	OFF	2nd	X	OFF	3rd	ON	X	2nd	3rd
   HINT: X: OFF (the ECM stops sending current to a malfunctioning solenoid valve)