GAUGE GP-O LEV 5051702 - Caterpillar

Illustration 1 g00755372
Schematic for the modulating valve (auxiliary)(No. 2)Test Step 1. CHECK FOR A SHORT TO THE + BATTERY CIRCUIT IN THE WIRE HARNESS
Turn the key start switch to the OFF position.
Remove the operator control panel on the right side in order to get to the ECM.
Disconnect the wire harness from the ECM.
Measure the resistance from contact 58 (wire E544-GN) to the following contacts of the wiring harness: contact 1, contact 7, contact 9, contact 13, contact 18, contact 29, contact 31, contact 45 and contact 62.Expected Result:The resistances should be greater than 5000 Ohms.Results:
OK - The resistances were greater than 5000 Ohms. Proceed to Test Step 2.
NOT OK - The resistance was less than 5000 Ohms on one of the readings.Repair: There is a short in the wire harness. Locate the short. Repair the wire harness or replace the wire harness. Stop.Test Step 2. CHECK FOR A SHORT IN THE CIRCUIT
Measure the resistance from contact 58 (wire E544-GN) to contact 42 (wire E540-PK).Expected Result:The resistance should be approximately 2.5 Ohms.Results:
OK - The resistance is approximately 2.5 Ohms. Proceed to Test Step 3.
NOT OK - The resistance is less than 2 Ohms. Proceed to Test Step 4.Test Step 3. CHECK FOR VOLTAGE IN THE CIRCUIT
Turn the key start switch to the ON position.
Measure the voltage from contact 58 (wire E544-GN) to contact 3 (wire 203-BK).Expected Result:The voltage should be near 0 volts.Results:
OK - The voltage is near 0 volts.Repair: The ECM is very unlikely to have failed. Reconnect all connections and visually inspect the wire harness. Verify that the diagnostic code still exists. If the diagnostic code still exists perform this Test Step again.Replace the ECM, if the cause of the diagnostic code was not found after the second attempt. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace". Stop.
NOT OK - The voltage is greater than 0 volts.Repair: There is a short in the wire harness. Locate the short. Repair the wire harness or replace the wire harness. Stop.Test Step 4. CHECK FOR A SHORT IN THE SOLENOID
Disconnect the connector for the modulating valve (No. 2).
Measure the resistance of the solenoid coil from contact 1 to contact 2.Expected Result:The resistance should be approximately 2.5 Ohms.Results:
OK - The resistance is approximately 2.5 Ohms.Repair: There is a short in the wire harness. Locate the short. Repair the wire harness or replace the wire harness. Stop.
NOT OK - The resistance is less than 2 Ohms.Repair: The solenoid coil has failed. Replace the coil. Stop.