Caterpillar Monitoring System for Electronic Modular Control Panel Caterpillar

In order to use the following procedure, you must know the connector contacts on the main display module that correspond to the diagnostic code. Use the Electrical System Schematic in the Service Manual for the engine in order to determine the contacts. Use the 7X-1710 Cable Probe when you are troubleshooting.

Note: The sensors are provided power from the main display module. Therefore, the main display module must be connected in order for the sensors to function.

Three items are checked in this test:

• A sensor signal is present at the main display module.

• The signal voltage increases with a corresponding increase in the system that is being monitored.

• The signal voltage decreases with a corresponding decrease in the system that is being monitored.

Procedure

1. Check the initial signal voltage.

   1. The engine coolant and the temperature sensors should be below operating temperature.

   2. Ensure that the engine coolant and temperature sensors are below normal. Ensure that the ECS is OFF and that the sensor is connected to the engine harness.

   3. Turn the ECS to the COOLDOWN position. DO NOT START THE ENGINE.

   4. At the engine harness connector for the main display module, measure the voltage and record the voltage (DCV) between the signal contact and frame ground. For correct operation, the approximate voltage is between 1.0 and 7.0 DCV.

      Expected Result: The voltage that is measured is within the specifications.

      Results:

      • YES - The voltage is between approximately 1.0 and 7.0 DCV. The signal voltage to the main display module is correct. Proceed to 2.

      • NO - The voltage is NOT between approximately 1.0 and 7.0 DCV. The signal voltage to the main display module is not correct. The probable cause is a faulty sensor. Replace the sensor. STOP.

2. Check the signal voltage with new conditions.

   1. Increase the temperature, the pressure or the fuel level of the system that is being tested. The following procedures are examples: run the engine in order to increase the temperature of the engine coolant, operate the implement controls in order to increase the hydraulic oil temperature and add fuel in order to increase the fuel level.

   2. At the engine harness connector for the main display module, measure the voltage (DCV) between the signal contact and frame ground.

   3. For correct operation, the voltage (DCV) is greater (and increases smoothly without step increases) than the voltage recorded in the previous test "Check the initial signal voltage".

      Note: The larger the change in the system that is being monitored, the greater the difference between the voltages of this test "Check the signal voltage with new conditions" and the previous test "Check the initial signal voltage".

      Expected Result:The voltage increases during the test procedure.

      Results:

      • OK - The voltage does increase during the test procedure and operates smoothly. The sensor is not faulty. STOP.

      • NOT OK - The voltage does not increase during the test procedure. The probable cause is a faulty sensor. Replace the sensor. STOP.