SPRING AS-GAS 4447873 - Caterpillar

Illustration 1 g01066105
Schematic for Magnetic Switches for the Start RelaysThis diagnostic code is recorded when the power train electronic control module (ECM) reads the current for the circuit of the start relays as above normal (short to ground). Note: Ensure that the diagnostic code for the start relays is active. Before performing this procedure, refer to table 1 in order to determine the connector contact number and the wire number that corresponds to the failed circuit.
Table 1
Information for Start Relays    
Fault    Connector Contact Number    Wire Number    
Starter Relays     J1-8 (1)     306-GN    
( 1 ) This is the connector contact number of the power train ECM.Note: All return lines for the start relays are joined. All return lines connect to contacts J1-7 and J2-3 (wire 975-WH) of the power train ECM.Note: The approximate coil resistance of each start relay is 15 to 65 Ohms.Possible causes of this diagnostic code are listed:
There is a harness fault.
A solenoid shorted to ground.System Response:The machine response is listed:
The engine will not start.Test Step 1. CHECK THE RESISTANCE OF THE START RELAYS.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness from both start relays.
Choose one start relay. Measure the resistance between the two contacts of the connector of the first start relay. Measure the resistance between the two contacts of the connector of the second start relay.Expected Result:The resistance for each start relay should be between 15 - 65 ohms.Results:
YES - The resistance of each start relay is correct. Proceed to Test Step 2.
NO - This start relay has failed.Repair: Replace the start relay. Stop.Test Step 2. CHECK THE START RELAYS FOR A SHORT TO GROUND.The disconnect switch and the key start switch remain in the OFF position. The start relays remain disconnected from the machine harness.
Measure the resistance from each start relay contact to frame ground.Expected Result:Each resistance should be greater than 5000 ohms.Results:
YES - The start relays and the harness for the start relay are correct. Proceed to Test Step 3.
NO - This start relay has failed.Repair: Replace the start relay. Stop.Test Step 3. CHECK THE SIGNAL CIRCUIT FOR THE START RELAYS FOR A SHORT TO GROUND.The machine harness remains disconnected from the start relays.
The disconnect switch and the key start switch remain in the OFF position.
Disconnect the machine harness connectors J1 and J2 from the power train ECM.
At machine harness connector J1 or J2, measure the resistance from the signal contact for the start relays to all possible sources of ground. Refer to table 1. The following contacts are possible ground sources: J1-2, J1-5, J1-7, J1-15, J1-16, J2-3 and frame ground.Expected Result:Each resistance should be greater than 5000 ohms.Results:
YES - The machine harness is correct. Proceed to Test Step 4.
NO - There is a short in the machine harness. The short is between the signal wire for the start relays and the circuit with a measurement of low resistance. Refer to the previous table.Repair: Repair the machine harness