5130, 5130B and 5230 Excavators, 784B, 785B, 785C, 789B, 789C, 793B and 793C Off-Highway Truck/Tractors and 992G, 994 and 994D Wheel Loaders Vital Information Management System (VIMS) Caterpillar

Sensor Signal Voltage - Test

Usage:

793B 1HL

Note: This procedure is performed while the VIMS interface module is connected to the sensor.

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Table 1
Specifications for the Sensor Signal Voltage Test.⁽¹⁾
Temperature Sensor
Temperature	Signal Voltage⁽²⁾	Duty Cycle⁽²⁾
−40 to 20°C (−40 to −4°F)	1.0 to 1.1 DCV	10 to 11%
−20 to 0°C (−4 to 32°F)	1.1 to 1.4 DCV	11 to 15%
0 to 20°C (32 to 68°F)	1.4 to 1.9 DCV	15 to 23%
20 to 40°C (68 to 104°F)	1.9 to 2.9 DCV	23 to 37%
40 to 60°C (104 to 140°F)	2.9 to 4.0 DCV	37 to 55%
60 to 80°C (140 to 176°F)	4.0 to 5.1 DCV	55 to 71%
80 to 100°C (176 to 212°F)	5.1 to 5.8 DCV	71 to 82%
100 to 120°C (212 to 248°F)	5.8 to 6.3 DCV	82 to 89%
120 to 140°C (248 to 275°F)	6.3 to 6.5 DCV	89 to 93%

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⁽¹⁾	These specifications may be used in Step 2 of the following procedure.
⁽²⁾	The voltages that are listed here are guidelines for troubleshooting. The values are not considered to be exact. The tolerance is ±10%. The tolerance depends on the condition of the harness. The voltage output should change smoothly with the change in temperature.

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Table 2
Specifications for Sensor Voltage Test⁽¹⁾
Temperature Sensor (Exhaust)
Temperature	Signal Voltage⁽²⁾	Duty Cycle ⁽²⁾
50 to 200 °C (122 to 392°F)	1.4 to 2.0 DCV	22 to 33%
200 to 400 °C (392 to 725°F)	2.0 to 2.8 DCV	35 to 50%
400 to 600 °C (725 to 1112°F)	2.8 to 3.7 DCV	50 to 67%
600 to 850 °C (1112 to 1562°F)	3.7 to 4.8 DCV	67 to 88%

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⁽¹⁾	These specifications may be used with Step 2 of the following procedure.
⁽²⁾	The voltages that are listed here are guidelines for troubleshooting. The values are not considered to be exact. The tolerance is ±10%. The tolerance depends on the condition of the harness. The voltage output should change smoothly with the change in temperature.

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Table 3
Specifications for Sensor Voltage Test⁽¹⁾
Pressure Sensor (AIR)
Air Pressure	Signal Voltage⁽²⁾	Duty Cycle⁽²⁾
0 to 200 kPa (0 to 29 psi)	0.9 to 1.8 DCV	10 to 27%
200 to 400 kPa (29 to 58 psi)	1.8 to 2.8 DCV	27 to 45%
400 to 600 kPa (58 to 88 psi)	2.8 to 3.7 DCV	45to 62%
600 to 800 kPa (88 to 115 psi)	3.7 to 4.6 DCV	62 to 80%
800 to 1000 kPa (115 to 145 psi)	4.6 to 5.5 DCV	80to 97%

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⁽¹⁾	These specifications may be used with Step 2 of the following procedure.
⁽²⁾	The voltages that are listed here are guidelines for troubleshooting. The values are not considered to be exact. The tolerance is ±10%. The tolerance depends on the condition of the harness. The voltage output should change smoothly with the change in air pressure.

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Table 4
Specifications for the Sensor Voltage Test ⁽¹⁾
Ultrasonic Fuel Level Sensor
Depth of Fuel (Deep Tank)⁽²⁾	Depth of Fuel⁽²⁾(Shallow Tank)	Signal ⁽³⁾ Voltage	Duty Cycle
0 to 500 mm (0 to 19.7 inch)	0 to 250 mm (0 to 9.9 inch)	0.6 to 1.9 DCV	6 to 25%
500 to 1000 mm (19.7 to 39.4 inch)	250 to 500 mm (9.9 to 19.7 inch)	1.9 to 3.2 DCV	25 to 45%
1000 to 1500 mm (39.4 to 59.1 inch)	500 to 750 mm (19.7 to 29.6 inch)	3.2 to 4.5 DCV	45 to 64%
1500 to 2000 mm (59.1 to 78.8 inch)	750 to 1000 mm (29.6 to 39.4 inch)	4.5 to 5.7 DCV	64 to 84%

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⁽¹⁾	These specifications may be used with Step 2 of the following procedure.
⁽²⁾	Connector contact 3 is used to program the sensor for the proper depth of the tank . Contact 3 is grounded for shallow tanks and open for deep tanks. See the Electrical System Schematic for the machine that is being serviced.
⁽³⁾	The voltages that are listed here are guidelines for troubleshooting. The values are not considered to be exact. The tolerance is ±10%. The tolerance depends on the condition of the harness. The voltage output should change smoothly as the signal changes.

Note: The actual fuel level may not agree with the sensor. The fuel level reading depends on the location of the sensor in the fuel tank.

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Table 5
Specifications for Sensor Voltage Test
Fuel Level Sensor (Resistive Type)
Machine	Fuel Level	Sensor Resistance	Buffer Duty Cycle
994	Empty	0-5 Ω	94-90%
994	Full	90-100 Ω	28-21%
992G	Empty	90-100 Ω	28-21%
992G	Full	0-5 Ω	94-90%

Procedure

Locate the suspect sensor. Identify the sensor wires and connector contacts. See Testing and Adjusting, "Pulse Width Modulated (PWM) Sensor - Test". DO NOT DISCONNECT ANY HARNESS CONNECTORS AT THIS TIME. Turn the key start switch to the ON position. DO NOT START THE ENGINE.

Note: Some sensors are powered by the VIMS interface modules and use 8 volts and other sensors are powered from the battery and use 24 volts. Refer to the Electrical System Schematic in order to determine the voltage that is required for the sensor that is being checked.

CHECK THE SENSOR POWER.
1. At the sensor connector, identify the +V and ground circuits.
2. Insert the 7X-1710 Multimeter Probe leads into the back of the sensor connector along side of the +V and ground circuit wires.
3. Measure the system voltage.
  Expected Result: The voltage is between 7.5 DCV and 8.5 DCV or the voltage is between 24 DCV and 29.5 DCV.
  Results:
  - OK - Voltage is between 7.5 DCV and 8.5 DCV or the voltage is between 24 DCV and 29.5 DCV. The system voltage is present. Proceed to Step 2.
  - NOT OK - Voltage is not between 7.5 DCV and 8.5 DCV or the voltage is not between 24 DCV and 29.5 DCV. There is an open circuit. Trace the +V and ground circuits in the machine harness. Repair the machine harness or replace the machine harness. STOP.
CHECK THE SIGNAL VOLTAGE.
1. At the sensor connector, identify the signal and ground circuits.
2. Insert the 7X-1710 Multimeter Probe leads into the back of the sensor connector along side of the signal and ground circuit wires.
3. Measure the signal voltage and record the signal voltage.
  Note: If more precise specifications of the signal voltage are necessary, use the specifications that are listed in the tables of “Specifications for Sensor Voltage Test”.
  Expected Result: The signal voltage is between approximately 1.0 DCV and 8.0 DCV.
  Results:
  - VOLTAGE is FROM 1.0 DCV TO 8.0 DCV. The signal voltage at the sensor is correct. Proceed to Step 3.
  - VOLTAGE is GREATER THAN 9.0 VDC. The voltage is NOT between approximately 1.0 DCV and 8.0 DCV. The signal voltage is not correct. Proceed to Step 4.
  - VOLTAGE is LESS THAN 1.0 DCV. The voltage is less than 1.0 DCV. Proceed to Step 5.
CHECK THE SIGNAL CIRCUIT OF THE MACHINE HARNESS.
1. At the machine harness connector for the main display module, identify the signal and ground circuits. DO NOT DISCONNECT THE HARNESS CONNECTOR.
2. Insert the 7X-1710 Multimeter Probe leads into the back of the machine harness connector along side of the signal and ground circuit wires.
3. Measure the signal voltage.
4. Compare this measurement with the voltage that was measured in the previous test “CHECK THE SIGNAL VOLTAGE”.
  Expected Result: The signal voltage is equal to the voltage that was recorded in Step 2a.
  Results:
  - OK - Signal voltage is equal to the voltage that was recorded in Step 2a. The VIMS interface module is receiving a valid signal voltage. If the problem still persists, further testing is required. Proceed to Step 6.
  - NOT OK - Signal voltage is NOT equal to the voltage that was recorded in Step 2a. The machine harness has an open in the signal or ground circuits. Repair the machine harness or replace the machine harness. STOP.
CHECK THE MACHINE HARNESS.
1. Signal voltage is greater than 7.0 DCV. The probable cause is a short to system voltage (+battery) in the machine harness or the sensor has failed.
2. Disconnect the machine harness connector for the sensor.
3. At the machine harness connector for the sensor, measure the voltage between the signal contact and the ground contact.
  Expected Result: The voltage is greater than 9.0 DCV.
  Results:
  - YES - Voltage is greater than 9.0 DCV. The voltage is not correct. The signal circuit of the machine harness is shorted to the +battery. Repair the machine harness or replace the machine harness. If the machine harness is not the cause, replace the VIMS module. STOP.
  - NO - Voltage is 7.0 ± 1.0 DCV. The voltage is correct for a good harness. The sensor has failed. Replace the sensor. STOP.
CHECK THE MACHINE HARNESS.
The signal voltage is less than 1.0 DCV. The probable cause is a short to ground in the machine harness or the sensor has failed.
1. Disconnect the machine harness connector for the sensor.
2. Measure the voltage between the signal contact and the ground contact.
  Expected Result: The voltage that is measured is less than 6.0 ± 0.5 DCV.
  Results:
  - YES - Voltage is less than 1.0 DCV. The voltage is not correct. The signal circuit of the machine harness is shorted to ground. Repair the machine harness or replace the machine harness. If the machine harness is not the cause, replace the VIMS module. STOP.
  - NO - Voltage is 7.0 DCV. The voltage is correct for a good harness and the main display module. The sensor has failed. Replace the sensor. STOP.
PERFORM THE SENSOR DYNAMIC TEST.