COUPLING 2649554 - Caterpillar

Illustration 1 g00530356
Schematic for the sensor power supply
This diagnostic code is recorded when the main display module reads the signal voltage. The voltage from the sensor is too low.Test Step 1. CHECK THE VOLTAGE AT THE MAIN DISPLAY.
Use the 7X-1710 Multimeter Probe in order to check the voltage at the connector for the main display module. Measure the voltage from contact 24 to contact 2 (ground). DO NOT disconnect the harness from the module. Expected Result:The voltage measures 8.0 0.5 DCV.Results:
YES - The voltage is 8.0 0.5 DCV. The sensor supply voltage is correct. Verify that the diagnostic code exists.Repair: It is unlikely that the main display module has failed. Exit this procedure and perform this procedure again. Also, recheck if the diagnostic code indicator is illuminated for this diagnostic code. If the cause of the diagnostic code is not found, replace the main display module. See Testing and Adjusting, "Module - Replace".STOP
NO - The voltage is NOT 8.0 0.5 DCV. The sensor supply voltage is NOT correct. Proceed to test step 2.Test Step 2. DISCONNECT THE SENSORS.
Continue to monitor the sensor supply voltage.
Disconnect one of the sensors that are connected to the +8 DCV sensor supply of the main display module from the machine harness.
After you disconnect the sensor, check the voltage reading on the multimeter. Expected Result:The voltage that is measured is 8.0 0.5 DCV.Results:
YES - The voltage is 8.0 0.5 DCV. The sensor supply is correct. The sensor that was just disconnected has failed.Repair: Replace the sensor.STOP
NO - The voltage is NOT 8.0 0.5 DCV. Repeat this test step for the remaining sensors. If the voltage is NOT correct after the remaining sensors are disconnected and tested. Continue to the next test step. Proceed to test step 3.Test Step 3. CHECK FOR A SHORT TO GROUND.
Turn the disconnect switch and the key start switch to the OFF position.
The sensors remain disconnected.
Disconnect the machine harness from the main display module.
At the machine harness connector for the main display module, measure the resistance between the frame ground and the sensor supply circuit (connector contact 24). Expected Result:The resistance that is measured is greater than 5000 ohms.Results:
YES - The resistance is greater than 5000 ohms. The harness circuit resistance is correct. The main display module has failed.Repair: It is unlikely that the main display module has failed. Exit this procedure and perform this procedure again. Also, recheck if the diagnostic code indicator is illuminated for this diagnostic code. If the cause of the diagnostic code is not found, replace the main display module. See Testing and Adjusting, "Module - Replace".STOP
NO - The resistance is less than 5000 ohms. The machine harness has failed. There is a short to ground in the machine harness.Repair: Repair the harness or replace the harness.STOP