DTC P2740 Transmission Fluid Temperature Sensor "B" Circuit; DTC P2742 Transmission Fluid Temperature Sensor "B" Circuit Low Input; DTC P2743 Transmission Fluid Temperature Sensor "B" Circuit High Input: Description

WARNING: This page is about a different car, the 2007 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.

The No. 2 ATF temperature sensor is on the transmission, just in front of the oil cooler inlet pipeline. If the ECM detects an abnormally high ATF temperature near this sensor, it illuminates the warning light.

HINT:

ATF temperature rises quickly when towing, climbing hills, in traffic, etc.
If the No. 2 ATF temperature sensor becomes short-circuited, the signal that indicates that the ATF temperature is 150°C (302°F) or higher is input in the ECM.

Vehicle conditions when the sensor is normal and when the sensor is short-circuited are indicated in the table below.

PROBLEM SYMPTOMS CHART

No. 2 ATF Temperature Sensor State	Detection Condition	Symptom	Recovery Condition
Sensor is normal	ATF temperature more than 150°C(275°F)	ATF temperature warning light remains ON	ATF temperature less than 135°C (275°F)*2
	ATF temperature more than 130°C (266°F)	Shift point too high	ATF temperature less than 110°C(230°F)
	When the conditions (a) and (b) are satisfied ATF temperature more than 130°C(266°F) Engine coolant temperature more than 95°C (203°F)	Lock up at 3rd gear*1	ATF temperature less than 110°C(230°F)*2 and engine coolant temperature more than 95°C (203°F)
Sensor is short-circuited	Any conditions	ATF temperature warning light remains ON Shift point too high	Symptoms still occur
Sensor is short-circuited	Engine coolant temperature more than 95°C (203°F)	Lock up at 3rd gear*1	Symptoms still occur
HINT: 1: When ATF temperature is normal, transmission lock-up occurs in 5th gear with the shift lever on D, and 4th gear with the shift lever on 4. 2: When ATF temperature is in the normal range, it decreases to less than 135°C (275°F) within 5 minutes with the shift lever on P or N in an idling state.

DTC DETECTION CONDITION AND TROUBLE AREA

DTC No.	DTC Detection Condition	Trouble Area
P2740	(a) and (b) are detected momentarily within 0.5 sec. when neither P2742 or P2743 are detected (1 trip detection logic): No. 2 ATF temperature sensor resistance is less than 79 Ω No. 2 ATF temperature sensor resistance is more than 156 kΩ HINT: Within 0.5 sec, the malfunction switches from (a) to (b) or from (b) to (a)	Open or short in No. 2 ATF temperature sensor circuit No. 2 ATF temperature sensor ECM
P2742	No. 2 ATF temperature sensor resistance is less than 79 Ω for 0.5 sec. or more (1 trip detection logic)	Short in No. 2 ATF temperature sensor circuit No. 2 ATF temperature sensor ECM
P2743	No. 2 ATF temperature sensor resistance is more than 156 kΩ when 15 minutes or more have passed after the engine start DTC is detected for 0.5 sec. or more (1 trip detection logic)	Open in No. 2 ATF temperature sensor circuit No. 2 ATF temperature sensor ECM