COUPLING 1131942 - Caterpillar

Illustration 1 g01451509
Schematic for Engine Starting SystemThe ECM activates the intermediate start relay when the key start switch is in the START position and the direction switch is in the NEUTRAL position. If CID 0444 or CID 0168 are present, the diagnostic code must be corrected before performing the following procedure "Check the key start switch". See Troubleshooting, "Diagnostic Code List".After the Power Train ECM detects the system voltage at the START input, the ECM will activate the intermediate starter relay. The following machine conditions are needed to start the engine:
The parking brake is engaged.
The transmission is in NEUTRAL.The starter relays have system battery voltage on one side of the relay contacts. When the starter relays are energized by the intermediate start relay, system battery voltage is directed through the closed relay contacts. Next, the starter solenoids for the starter will energize. The starter solenoid contacts will close and +battery voltage will be applied to the starter in order to crank the engine for starting.Perform the following procedure if the engine will not crank with the key start switch in the START position.Note: Refer to the engine service manual for your machine if the engine cranks but the engine is not starting. Verify that there are no active CID 0444 diagnostic codes for the intermediate starter relay. If a diagnostic code for the relay is active, troubleshoot the diagnostic code before attempting to start the engine.Test Step 1. Verify That The Machine Conditions Are Correct
Verify that the following conditions are correct:
The disconnect switch is in the ON position.
The breaker for the starting system is not open.
The parking brake is engaged.
The transmission is in NEUTRAL.Expected Result:One or more of the listed machine conditions was not correct.Results:
YES - One or more of the listed machine conditions was not correct. Repair: Ensure that all the listed machine conditions are correct. Then attempt to start the engine again.STOP
NO - All of the listed machine conditions are correct. The engine will not crank and there are not any diagnostic codes for the intermediate starter relay. Proceed to Test Step 3.Test Step 2. Check The RelaysThe key start switch is in the OFF position.
Obtain the aid of another technician. The other technician can place the key start switch in the START position. Observe the starter relays. The relays should create an audible "click" when the key start switch is first moved to the START position. Expected Result:The relays are being energized by the intermediate start relay. Results:
OK - The relays are being energized by the intermediate start relay. Proceed to Test Step 3.
NOT OK - The relays are not being energized by the intermediate start relay.Repair: There is a problem in the circuit for the starter relay(s). Refer to the Troubleshooting section of this manual. Perform the diagnostic code procedure for the CID 0444 FMI 05 diagnostic code in order to find the problem. The CID 0444 FMI 05 indicates that the current is below normal or the circuit is open for the intermediate start