FAIL-SAFE/BACKUP FUNCTION
When a malfunction of a main sensor or actuator is detected by the PCM, the transaxle is controlled by preset control logic to maintain safe conditions for driving.
The following table shows how the fail-safe/backup function affects vehicle driveability and operation.
| MALFUNCTIONING ITEM | JUDGEMENT CONDITION | CONTROL DEFAULT DURING MALFUNCTION | |
|---|---|---|---|
| Input shaft speed sensor | If no output pulse from the input shaft speed sensor is detected for one second or more when the vehicle speed is 30km/h (19 mph) or greater. | The diagnostic trouble code is recorded when the malfunction occurs during 4 monitoring periods in one drive cycle. When the judgment condition is met, the transaxle holds 3rd gear or 2nd gear, depending on speed, as a fail-safe. | |
| Output shaft speed sensor | The output signal from the output shaft speed sensor is not present for one second or more while the vehicle is driven. | The diagnostic trouble code is recorded when the malfunction occurs during 4 monitoring periods in one drive cycle. When the judgment condition is met, the transaxle holds 3rd gear or 2nd gear, depending on speed, as a fail-safe. | |
| Low-reverse solenoid valve | Solenoid valve resistance is below 2.7 ohms for 0.32 seconds. | The diagnostic trouble code is recorded when the malfunction occurs during 4 monitoring periods in one drive cycle. When the judgment condition is met, the A/T control relay is turned off. The transaxle will only operate in 3rd and reverse gears until the system is repaired. | |
| Underdrive solenoid valve | |||
| Second solenoid valve | |||
| Overdrive solenoid valve | |||
| Reduction solenoid valve < 5A/T > | |||
| Torque converter clutch solenoid valve | |||
| Incomplete shifting | 1st | The gear ratio value from the output shaft speed sensor is not the same as the output from the input shaft speed sensor for one second after shifting has been completed. | The diagnostic trouble code is recorded when the malfunction occurs during 4 monitoring periods in one drive cycle. When the judgment condition is met, the A/T control relay is turned off. The transaxle will only operate in 3rd and reverse gears until the system is repaired. |
| 2nd | |||
| 3rd | |||
| 4th | |||
| 5th < 5A/T > | |||
| Reverse | |||
| A/T control relay | A/T control relay voltage is less than seven volts for 0.1 second after the ignition switch is turned "ON". | The A/T control relay is switched off. The transaxle will only operate in 3rd and reverse gears until the system is repaired. | |
| Malfunction in the PCM | Malfunction has occurred in the PCM. | The A/T control relay is switched off. The transaxle will only operate in 3rd and reverse gears until the system is repaired. | |
FAIL-SAFE/BACKUP FUNCTION