A750E Automatic Transmission

A750E AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: P0722: Output Speed Sensor Circuit No Signal
P0722 - Output Speed Sensor Circuit No Signal

DESCRIPTION

The speed sensor (SP2) detects the rotation speed of the transmission output shaft and sends signals to the ECM. The ECM determines the vehicle speed based on these signals. An AC voltage is generated in the speed sensor (SP2) coil as the parking gear mounted on the rear planetary gear assembly rotates, and this voltage is sent to the ECM. The parking gear on the rear planetary gear is used as the timing rotor for this sensor. The gear shift point and lock-up timing are controlled by the ECM based on the signals from the vehicle speed sensor and the throttle position sensor.









Using an oscilloscope:

Check the waveform between terminals SP2+ and SP2- of the ECM connector.





Standard:

Refer to the illustration.





MONITOR DESCRIPTION

The output speed sensor monitors the output shaft speed. The ECM controls the gearshift point and the lock up timing based on the signals from the output speed sensor and throttle position sensor.

If the ECM detects no signal from the output shaft speed sensor even while the vehicle is moving, it will conclude that there is a malfunction in the output speed sensor. The ECM will illuminate the MIL and set the DTC.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





COMPONENT OPERATING RANGE





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
Perform the universal trip to clear permanent DTCs .

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.

1. Warm up the engine.

2. Turn the ignition switch off.

3. Connect the Techstream to the DLC3.

4. Turn the ignition switch to ON.

5. Turn the Techstream on.

6. Enter the following menus: Powertrain / Engine and ECT / Data List.

7. According to the display on the Techstream, read the Data List.

Engine and ECT





HINT
- SPD (SP2) is always 0 while driving:
- Open or short in the sensor or circuit.
- The SPD (SP2) value displayed on the Techstream is much lower than the actual vehicle speed:
- Sensor trouble, improper installation, or intermittent connection trouble in the circuit.

PROCEDURE

1. INSPECT SPEED SENSOR (SP2) INSTALLATION

(a) Check the speed sensor (SP2) installation.





OK:

The installation bolt is tightened properly and there is no clearance between the sensor and transmission case.

NG -- SECURELY INSTALL OR REPLACE SPEED SENSOR (SP2)
OK -- Continue to next step.

2. INSPECT SPEED SENSOR (SP2)

(a) Disconnect the speed sensor (SP2) connector from the transmission.





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPLACE SPEED SENSOR (SP2)
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (SPEED SENSOR (SP2) - ECM)

(a) Connect the speed sensor (SP2) connector.





(b) Disconnect the connector from the ECM.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM Removal