BENDIX SD-15-4106 guide

6.Record the output voltage when the pedal is in the idle position (V1). Then slowly depress the pedal. When the ohm meter shows that the resistance has changed from “overload” to about .003 ohms (or from .003 ohms to “overload”), stop depressing the pedal. Record the voltage (Vx) registered with the pedal in this position. Then press the pedal to the full throttle position and record the output voltage (V2).

7.Calculate the “switch point percentage” using the formula below.

Switch point percentage = ((Vx-V1)/(V2-V1))*100

Vx = Output voltage when the switch changed

V1 = idle voltage

V2 = full throttle voltage

DIGITAL

VOLT/

POWEROHM

SUPPLY METER (9-16 VDC)

	PIN C
RESISTOR	GROUND
RESISTOR
TEST LOAD	PIN B
47,000 OHM	VOUT
	(OUTPUT)

PIN A VREF (INPUT)

POTENTIOMETER

PC. NO. ON THIS

SURFACE

FIGURE 7 - ET-2™TREADLE ELECTRICAL TEST

SCHEMATIC FOR THE CUMMINS CONNECTOR

8.The switch point percentage should be between 3% to 10%. If it is not with in this range adjust the potentiometer by loosening the mounting screws and turning the potentiometer within the range allowed by the mounting holes. Repeat steps 1-7 again. If you can not obtain the proper switch point percentage, replace with a new ET-2™treadle, available at your nearest Bendix parts outlet.

9.After a successful test the vehicle may be returned to service.

The following instructions are for a bench test for the potentiometer used with Cummins engines.

10.Unplug the cable assembly from the potentiometer’s integral connector by lifting the lock tab and pulling the connectors until they disengage. Inspect cable assembly for loose terminals, frayed wires, corrosion, wear, or physical damage. Check end-to-end electrical continuity at terminals. NOTE: Potentiometer pin locations will remain constant (see Figure 5). However, cable assembly connector pin out may vary from engine to engine.

11.Remove the ET-2™treadle from the vehicle.

12.Secure the ET-2™treadle to a smooth, flat surface in such a way that it does not twist the unit.

13.Connect the potentiometer to the volt meter and power supply as shown in Figure 5. NOTE: Power supply can be a 12 VDC vehicle battery in good condition and with known voltage output.

14.Verify that the closed throttle (idle) output voltage, as a percentage of supply voltage, is within the limits listed in Figure 2.

15.Depress the treadle to its full throttle position. The output voltage, as a percentage of supply voltage, should be within the limits listed in Figure 2. e.g. Testing a Detroit Diesel ET-2™Treadle Potentiometer: Battery = 10 VDC. Full throttle = 9 VDC. 9/10 x 100 = 90%.

16.Make several full applications and record idle position voltage each time. Verify that idle position voltage does not vary by more than .4% (.02 volts). If the ET-2™treadle does not operate within its specified ranges, service the unit, or replace it with a new ET-2™treadle, available at your nearest Bendix parts outlet.

Test 3: For Cummins engines (with integrated switch

and sensor (ISS): For use only with the Cummins Celet Plus and later editions of the ECU. This sensor can not be used to replace the separate potentiometer & idle validation switch. To do this a new ET-2™treadle with the ISS must be purchased.

Test 1: Where the set resistance and voltage is shown on a label. The Cummins potentiometer on the ET-2™treadle has an integral idle validation switch. It also has a set resistance value marked on the cover, which needs to be used to properly install the potentiometer. The drive slot in the potentiometer should engage with the drive tang at the end of the drive shaft. Next rotate the potentiometer until the hole in the metal sleeve matches the mounting holes on the actuator base. Loosely screw the potentiometer in place but do not tighten. Connect an ohmmeter to pins 3 (APS output) and 4 (APS ground) as shown in Figure 8. Now the installer should read the set resistance value marked on the label. Rotate the