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• Ahmed Rezk

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Product: WHEEL LOADER Model: 966H WHEEL LOADER TAL02276 Configuration: 966H Wheel Loader TAL00001-UP (MACHINE) POWERED BY C11 Engine

Systems Operation 966H Wheel Loader and 972H Wheel Loader Power Train Media Number -RENR8845-02

Publication Date -01/12/2011

Date Updated -06/12/2011 i02411012

Sensors SMCS - 1907; 1912; 301T; 3141; 3175

Sensors provide information to the power train electronic control module (ECM) about changing conditions. The sensor signal changes proportionally to the changing conditions. The following type of sensor signals are recognized by the power train ECM:  

Frequency signals: The frequency (Hz) of the sensor signal varies as the condition changes. Pulse width modulated signals (PWM): The duty cycle of the sensor signal varies as the condition changes. The frequency of this signal is constant.

g00288430 Illustration 1 Pulse Width Modulated Signal

Speed Sensors (Transmission and Torque Converter Output)

g00288428 Illustration 2 Speed Sensor

There are two transmission speed sensors and one torque converter output speed sensor on the machine. The speed sensors are inputs of the power train ECM. These speed sensors are frequency sensors. Frequency sensors produce a signal (Hz) which varies as the condition changes. The sensor generates an approximate sine wave signal from the gear teeth as the gear teeth pass the sensor. The sensor produces a signal that equals one pulse per gear tooth. This signal is sent to the power train ECM. The power train ECM measures the frequency of the signal in order to determine the speed. In the case of dual sensors, the power train ECM receives signals from the speed sensors and the ECM uses the difference in input from the speed sensors in order to determine the direction of the system. The power train ECM uses the input from the speed sensors in order to regulate transmission shifts. Each speed sensor has two connections to the power train ECM (+ and -). The power train ECM sends the speed information to other electronic control modules via the CAT Data Link. For all of the speed sensors, connector contact 2 is the signal line and connector contact 1 is the return line. Two intermediate speed sensors (if equipped) measure intermediate transmission speed. Two transmission speed sensors measure transmission output speed. The power train ECM uses the pairs of speed sensors to determine the direction of rotation. Note: The speed sensors are used to diagnose each other during normal operation. The power train ECM periodically checks the value from the speed sensor. If an incorrect value is found, the power train ECM will log a service code that indicates a fault for a speed sensor circuit.

Reference: For more information on diagnostic operations for the power train electronic control system, refer to Systems Operation, "Power Train Electronic Control System" for the machine that is being serviced. Reference: For more information on the CAT Data Link, refer to the Service Manual module Systems Operation, "CAT Data Link" for the machine that is being serviced. Reference: For more information on the power train electronic control module (ECM), refer to the Service Manual module Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.

Temperature Sensor (Transmission Oil )

g01193340 Illustration 3 Transmission Oil Temperature Sensor (1) Signal wire (2) Ground wire

The transmission oil temperature sensor is a passive sensor. As the temperature of the oil changes, the resistance in the sensor will change. This change in resistance changes the voltage that is seen by the power train ECM for the sensor. The power train ECM measures transmission oil temperature from the voltage of the transmission oil temperature sensor. The power train ECM uses the oil temperature reading in order to adjust the shift times of the transmission. The

power train ECM adjusts the shift times of the transmission in order to provide smooth shifts over the various ranges of the transmission oil temperature. Reference: For more information on the operation of the machine, refer to the Service Manual module Operation and Maintenance Manual for the machine that is being serviced. Reference: For more information on the power train electronic control module (ECM), refer to the Service Manual module Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.

Position Sensor (Left Pedal)

g00779650 Illustration 4 Position Sensor (Left Brake Pedal)

The position sensor (left brake pedal) sends an input to the ECM. The sensor will continuously update the power train ECM on the position of the left pedal. The left pedal position sends a change in the input signal to the power train ECM. The ECM records the change of position. Then, the ECM activates the appropriate solenoid valve. The position sensor (left brake pedal) is a PWM sensor. The sensor continuously generates a PWM signal. The duty cycle varies in proportion to the position of the lever. The ECM receives the PWM signal from the position sensor. The ECM measures the duty cycle in order to determine the position of the lever. The frequency of the sensor signal is constant at 500 Hz. The

machine electrical system provides +battery voltage to the lever position sensor for operating power.

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