Toyota Venza: Intermediate Shaft Speed Sensor "A" Circuit (P0791,P0793)

Toyota Venza Service Manual / U660e Automatic Transmission / Transaxle / Automatic Transaxle System / Intermediate Shaft Speed Sensor "A" Circuit (P0791,P0793)

DESCRIPTION

This sensor detects the rotation speed of the counter gear which shows the output speed of transaxle. By comparing the input turbine speed signal (NT) with the counter gear speed sensor signal (NC), the TCM detects the shift timing of the gears and appropriately controls the engine torque and hydraulic pressure according to various conditions, thus, providing smooth gear shifts.

Text in Illustration

*1	Counter Gear	*2	Clutch Drum
*3	Output Speed Sensor NC	*4	Input Speed Sensor NT

DTC No.	DTC Detection Condition	Trouble Area
P0791	When the speed sensor input voltage is either more than 1.9 V or less than 0.1 V for 2 seconds or more. (1-trip detection logic)	Transmission revolution sensor (speed sensor NC) Transmission wire TCM
P0793	When the vehicle speed is 25 km/h (15.5 mph) or higher, the counter gear speed is less than 300 rpm for 2 seconds or more. (1-trip detection logic)

MONITOR DESCRIPTION

The NT terminal of the TCM detects a revolution signal from the speed sensor (NT) (input RPM). The TCM calculates a gear shifts by comparing the speed sensor (NT) with the speed sensor (NC).

While the vehicle is operating in 2nd, 3rd, 4th or 5th gear with the shift lever in D, if the input shaft revolution is less than 300 rpm*1 although the output shaft revolution is more than 1000 rpm*2, the TCM interprets this as a fault, illuminates the MIL and stores the DTC.

*1: Pulse is not output or is irregularly output.

*2: The vehicle speed is 50 km/h (31 mph) or more.

MONITOR STRATEGY

Related DTCs	P0791: Speed sensor (NC)/Range check P0793: Speed sensor (NC)/Verify pulse input
Required sensors/Components	Speed sensor (NT), Speed sensor (NC)
Frequency of operation	Continuous
Duration	2 sec.
MIL operation	Immediate
Sequence of operation	None

TYPICAL ENABLING CONDITIONS

The monitor will run whenever this DTC is not present.	P0500 (VSS) P0748, P0778, P0798 (Shift solenoid valve (range))
Vehicle speed	15.5 mph (25 km/h) or more
Battery voltage	8 V or more
Ignition switch	ON
Starter	OFF

TYPICAL MALFUNCTION THRESHOLDS

P0791:

Intermediate shaft speed sensor voltage

Less than 0.1 V or more than 1.9 V

P0793:

Intermediate shaft speed sensor revolution

Less than 300 rpm

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Perform the universal trip to clear permanent DTCs (See page ).

1. DATA LIST

HINT:

Using the Techstream to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.

NOTICE:

In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.

(a) Warm up the engine.

(b) Turn the ignition switch off.

(d) Turn the ignition switch to ON.

(e) Turn the Techstream on.

(f) Enter the following menus: Powertrain / ECT / Data List.

(g) According to the display on the Techstream, read the Data List.

Item	Measurement Item/Range (display)	Normal Condition
SPD (NC)	Counter Gear Speed/ display: 50 r/min	-

HINT:

SPD (NC) is always 0 while driving: Open or short in the sensor or circuit.
SPD (NC) is always more than 0 and less than 300 rpm while driving the vehicle at 50 km/h (31 mph) or more: Sensor trouble, improper installation, or intermittent connection trouble of the circuit.

PROCEDURE

1.	INSPECT SPEED SENSOR (SENSOR INSTALLATION)

(a) Remove the valve body assembly.

(b) Make sure that the connector is properly connected, and check the speed sensor installation.

OK:

The installation bolts are tightened properly and there is no clearance between the sensor and transaxle case.

REPAIR OR REPLACE SPEED SENSOR

2.	INSPECT TRANSMISSION WIRE

(a) Remove the TCM.

(b) Disconnect the speed sensor connector from the transmission wire.

Standard Resistance:

Tester Connection	Condition	Specified Condition
3 (NCO) sensor side - 3 (NCO) TCM side	Always	Below 1 Ω
4 (NCB) sensor side - 4 (NCB) TCM side	Always	Below 1 Ω
3 (NCO) sensor side - Body ground	Always	10 kΩ or higher
4 (NCB) sensor side - Body ground	Always	10 kΩ or higher
3 (NCO) sensor side - All other terminals except 4 (NCB) sensor side	Always	10 kΩ or higher
4 (NCB) sensor side - All other terminals except 3 (NCO) sensor side	Always	10 kΩ or higher

Text in Illustration

Component without harness connected

(Transmission Wire)

TCM side

Sensor Side

REPLACE TRANSMISSION WIRE

3.	REPLACE SPEED SENSOR

(a) (See page ).

4.	CHECK IF DTC OUTPUT RECURS (SEE IF DTC P0791 AND/OR P0793 IS OUTPUT AGAIN)

(a) Connect the Techstream to the DLC3.

(b) Start the engine and turn the Techstream on.

HINT:

Write down the currently output DTCs before clearing them.

(d) Perform the monitor drive pattern (See page ).

(e) Enter the following menus: / ECT / DTC.

(f) Read the DTCs using the Techstream.

Display (DTC Output)	Proceed to
Only "P0791 or P0793" is output	A
No output	B

REPLACE TCM

END

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