CAMSHAFT 2401856 - Caterpillar

Illustration 1 g01238267
Parking brake switch connectionsThe parking brake switch has two inputs to the ECM. The two inputs are normally open and normally closed. During normal operation, one of the inputs is open to ground. The other input is closed to ground.An FMI 04 diagnostic code is recorded when the status of both the inputs are grounded at the same time.The possible causes of this diagnostic code are listed below:
The parking brake switch has failed.
The "ON" signal circuit is shorted to ground.
The "OFF" signal circuit is shorted to ground.
The ECM has failed. This is unlikely. Ensure that the CID 070 FMI 04 code is active before performing this procedure.Test Step 1. CHECK THE SWITCH IN THE OFF POSITION
Turn the key start switch to the OFF position.
Disconnect the machine harness connector from the switch.
Place the parking brake switch in the in the OFF position.
At the underside of the switch, measure the resistance between contact 5 and contact 4 of the switch connector.
At the underside of the switch, measure the resistance between contact 5 and contact 6 of the switch connector.Expected Result:With the switch in the OFF position, the resistance should be less than 5 ohms between contact 5 and contact 4 and the resistance should be greater than 5000 ohms between contact 5 and contact 6.Results:
OK - The resistance checks are correct. Proceed to Test Step 2.
NOT OK - The resistance is not within an acceptable range. The switch has failed. Repair: Replace the parking brake switch. Verify that the new switch corrects the diagnostic code.STOPTest Step 2. CHECK THE SWITCH IN THE ON POSITIONThe machine harness remains disconnected from the switch.
Place the switch in the ON position.
At the underside of the switch, measure the resistance between contact 5 and contact 4.
At the underside of the switch, measure the resistance between contact 5 and contact 6.Expected Result:With the switch in the ON position, the resistance should be less than 5 ohms between contact 5 and contact 6 and the resistance should be greater than 5000 ohms between contact 5 and contact 4.Results:
OK - The resistance measurements are correct. Proceed to Test Step 3.
NOT OK - The resistance is not within an acceptable range. The switch has failed.Repair: Replace the parking brake switch. Verify that the new switch corrects the diagnostic code.STOPTest Step 3. CHECK THE SIGNAL CIRCUITS FOR A SHORT TO A GROUND CIRCUITThe machine harness remains disconnected from the switch.
Disconnect the ECM machine harness connectors J1 and J2 from the ECM.
At the machine harness connector J2, measure the resistance between contact J2-60 (wire U734-GN) and all of the J1 contacts that are connected to -battery (frame ground). The J1 contacts that are connected to -battery are J1-13, J1-23, J1-32 and J1-70.
At the machine harness connector J2, measure the resistance between contact J2-61 (wire U735-GY) and all of the J1 contacts that are connected to -battery (frame ground). The J1 contacts that are connected to -battery are J1-13, J1-23, J1-32 and J1-70.Expected Result:All of the resistance measurements should be greater