WASHER, BACK 0779779 - Caterpillar

Illustration 1 g01044383
Schematic for the auxiliary control circuit The diagnostic procedures that follow are based on the fact that the auxiliary control ECM is recieving + battery power through the auxiliary hydraulics fuse wire 163-WH at contact 1 and that the ECM has a good ground connection through wire 203-BK at contact 2. Always ensure that the power and ground conditions are correct at the ECM before performing these procedures.Note: This procedure will require the removal of contacts from the ECM connector and/or the auxiliary control connector in order to make diagnostic checks while power is supplied to the auxiliary control. A 151-6320 Removal Tool is used for the ECM connector. A 6V-4741 Extractor is used for the auxiliary control connector.Test Step 1. CHECK THE DUTY CYCLE OF THE AUXILIARY CONTROL AT THE ECM
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.
Remove the wire harness connector from the ECM.
Using the 151-6320 removal tool, remove contact 62 (wire N997-WH) from the connector.
Connect the wire harness connector to the ECM.
Turn the key start switch to the ON position.
Measure the duty cycle of the auxiliary control from the removed contact 62 to frame ground.Expected Result:The duty cycle should be 50% 3%.Results:
OK - The duty cycle is 50% 3%. Proceed to Test Step 2.
NOT OK - The duty cycle is not 50% 3%. Proceed to Test Step 3Test Step 2. ACTUATE THE AUXILIARY CONTROL AND CHECK THE DUTY CYCLE AT THE ECM
Actuate the auxiliary control upward and measure the duty cycle of the auxiliary control from contact 62 to frame ground.
Actuate the auxiliary control downward and measure the duty cycle of the auxiliary control from contact 62 to frame ground.Expected Result:The duty cycle should vary from approximately 20% at the most upward position to 80% at the most downward position.Results:
OK - The duty cycle is approximately 20% at the most upward position and the duty cycle is approximately 80% at the most downward position.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 the Test Steps 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 duty cycle is above 83% or the duty cycle is below 18%. Proceed to Test Step 3Test Step 3. CHECK THE DUTY CYCLE OF THE AUXILIARY CONTROL AT THE AUXILIARY CONTROL
Turn the key start switch to the OFF position.
Locate the 12 pin connector from the auxiliary control and disconnect the 12 pin connector from the machine harness.
Use a 6V-4147 Extractor in order to remove the wire N997-WH which is leading to the auxiliary control from contact 3 of the 12 pin connector.
Reconnect the 12 pin connector to the machine harness connector.
Turn the key start switch to