Fail-Safe/Backup Function

WARNING: This page is about a different car, the 2005 Dodge Stratus and 2005 Chrysler Sebring. However, it is still accessible from the selected car via links, so may be relevant.

When a malfunction of a main sensor or actuator is detected by the PCM, the transaxle is controlled by pre-set control logic to maintain safe conditions for driving.

The following table shows how the fail-safe/backup function affects vehicle driveability and operation.

FAIL-SAFE/BACKUP FUNCTION REFERENCE

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 30 km/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 judgement 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 judgement 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 judgement 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
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 judgement 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
	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.