AP-655C and BG-2255C Asphalt Pavers Propel System Caterpillar

Testing and Adjusting the Position Sensor for the Decel Pedal (Service Brake Control)

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Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manual. Failure to follow the instructions or heed the warnings could result in injury or death. Contact any Caterpillar dealer for replacement manuals. Proper care is your responsibility.

Introduction

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Decel Pedal on Operator Station

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Position Sensor

The sensor for the decel pedal generates a PWM signal. The duty cycle of the signal will vary in proportion to the amount of pressure that is applied to the service brake control. The electronic control module (ECM) receives the PWM signal from the sensor. In addition, the ECM provides battery voltage to the sensor. As the signal is sent to the ECM, the ECM reads the duty cycle. The ECM then sends a signal to the (EDC) electronic displacement control on the propel pump. The signal will vary with the amount of pressure on the decel pedal. As the pedal is depressed completely, the signal fro the ECM is zero.

Required Tools

Hydraulic test procedures may be performed using either one of the following test equipment:

• Caterpillar DataView

• Standard Multimeter

Caterpillar DataView Tool

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Caterpillar DataView Caterpillar DataView is a PC based diagnostic tool. The Caterpillar DataView accepts a maximum of nine standard Caterpillar sensors for measurements on the machine. The signal is transmitted to a personal computer and the information is displayed.

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Caterpillar DataView Electrical Test Group

The following table provides a list of the required tools if Caterpillar DataView is used in order to perform the following test procedure. Caterpillar DataView is not shown in the following test procedure.

Standard Tools

There are various tools that may be used in order to test the PWM signal or the duty cycle of the position sensor. A few of the tools are listed below.

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Digital Multimeter Group

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Fluke Multimeter

Test Procedure

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Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.

Perform the following procedure before you perform the test procedure that follows:

• Park the machine on a level area that is clear from all equipment, material, and personnel.

• Verify that the service brake system and the parking brake system are in good working order.

• Apply the parking brake.

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1. Locate the main console on the machine. The main console is located directly in the center of the two operator stations.

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2. Loosen the two screws on the door of the main console.

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3. Locate "J1" connector (1) on the electronic control module (ECM) in the center main console.

4. Ensure that the engine start switch is turned to the OFF position.

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5. Connect the ground clip on multimeter (A1) to the ground post or one of the mounting bolts.

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Illustration 11	g00935373
ECM inside Main Console (1) J1 Connector (2) "Pin 2"

Note: The position sensor for the left decel pedal and the position sensor for the right decel pedal are connected into "Pin 2".

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Illustration 12	g00951356

6. Insert one of the spoons or probes on multimeter (A1) into "Pin 2" (2) on "J1" connector (1) .

7. Ensure that the multimeter is set at % or the duty cycle setting.

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Illustration 13	g00935384
Main Console

8. Turn the engine start switch to the ON position. Do not start the engine.

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Illustration 14	g00935207
Decel Pedal on Operator Station

9. As the decel pedal in the UP position or STATIONARY position, multimeter (A1) should have a duty cycly reading of 85% ± 35%. If the duty cycle reading is not within these limits, an adjustment needs to be made.

10. Slowly depress the decel pedal and observe multimeter (A1). The duty cycly reading should slowly decrease with no fluctuation until the decel pedal is fully depressed. Multimeter (A1) should have a duty cycle reading of 35% ± 3. If the duty cycle reading fluctuates erratically, replace the sensor. If the readings are not within these limits, an adjustment needs to be made.

11. Leave the test equipment in place as you adjust the sensor.

Adjustment Procedure

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Main Console

Note: Select the left operator station first. Proceed with the adjustment or replacement. Proceed to check the right operator station. Each station must be retested independently. Use the operator station select switch on the main console in order to switch the operator stations.

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Illustration 16	g00935543
Left Operator Station

1. Loosen the screws. Remove the panel below the operator station at the location of the decel pedal.

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Illustration 17	g00933936
Exploded View of Decel Pedal and Sensor

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2. Locate position sensor (1) on the back of decel pedal (2) .

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Illustration 19	g00951377
Bottom View of the Sensor (1) Position sensor (2) Decel pedal (3) Mounting screws

3. Loosen mounting screws (3). The mounting screws are located on the left side of the sensor. Rotate position sensor (1) until the mark on the sensor and the mark on the housing are aligned.

4. Retest the sensor. Multimeter (A1) should have a duty cycle reading of 85% ± 3 with the decel pedal in the UP position or the STATIONARY position.

5. Retest the sensor. Depress the decel pedal on the operator station and observe the duty cycle reading. The duty cycle reading should slowly decrease and there should be no fluctuation in the reading as the pedal is fully depressed. The duty cycle reading on multimeter (A1) should be 35% ± 3. Retest the sensor and adjust the sensor until the correct reading is read.

6. Tighten mounting screws (3) on position sensor (1) .

7. If a reading of 15% to 85% could not be obtained, replace the sensor. Repeat the procedure for the other operator station.

8. Replace the panel on the operator station.

9. Tighten the two screws on the main console.

10. Turn the engine start switch to the OFF position.

11. Remove the tooling.