GSIC - Global Service Information Center

# ELECTRONIC CONTROLLED AUTOMATIC TRANSMISSION SYSTEM > FAIL-SAFE CHART

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FAIL-SAFE CHART

This function minimizes the loss of the ECT functions when a malfunction occurs in each sensor or solenoid.
Fail-safe function:
If either of the shift solenoid valve circuits develops an open or short, the TCM turns the other shift solenoid ON and OFF to shift to the gear positions shown in the table below. The TCM also turns the shift solenoid valve SL OFF at the same time. If both solenoids are malfunctioning, electronic hydraulic control does not operate and must be performed manually. Manual shifting as shown in the following table must be performed.
In case of a short circuit, the TCM stops sending current to the circuit.

Malfunction Part | Function
DTC P0710, P0712 and P0713: ATF Temperature Sensor | During malfunction of ATF temperature sensor, system fixes ATF at 80°C (176°F)
DTC P0722: No. 2 Vehicle Speed Sensor (SP2) | During No. 2 vehicle speed sensor malfunction, shift lever control is effected through input speed sensor signal (NC0) or engine speed signal (NE)
DTC P0973, P0974, P0976 and P0977: Shift Solenoid Valve S1, S2 | Current to the failed solenoid valve is cut off and control is effected by operating other solenoid valves with normal operation
DTC P2716: Shift Solenoid Valve SLT | During solenoid valve SLT malfunction, current to solenoid valve is stopped Because this stops line pressure control, shift shock increases However, shifting is effected through normal clutch pressure control
DTC P2769 and P2770: Shift Solenoid Valve SL | During solenoid valve SL malfunction, current to solenoid valve is stopped Because this stops lock-up control, fuel economy decreases

Position | Normal | Shift Solenoid S1 Malfunctioning | Shift Solenoid S2 Malfunctioning | Both Solenoids 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 | OFF | 1st | X | ON | 3rd | ON | X | 1st | O/D
ON | ON | 2nd | X | ON | 3rd | OFF | X | O/D | O/D
OFF | ON | 3rd | X | ON | 3rd | OFF | X | O/D | O/D
OFF | OFF | O/D | X | OFF | O/D | OFF | X | O/D | O/D
2 | ON | OFF | 1st | X | ON | 3rd | ON | X | 1st | 3rd
ON | ON | 2nd | X | ON | 3rd | OFF | X | 3rd | 3rd
OFF | ON | 3rd | X | ON | 3rd | OFF | X | 3rd | 3rd
L | ON | OFF | 1st | X | OFF | 1st | ON | X | 1st | 1st
ON | ON | 2nd | X | ON | 2nd | ON | X | 1st | 1st

HINT:

  X: Malfunction