TUBE ASSEM. 4N6123 - Caterpillar

Illustration 4 g01155187
Connector for the engine speed/timing sensors
(1) Speed/timing sensor (−)
(2) Speed/timing sensor (+)
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the engine speed/timing sensor.
Check the allen head screw for each ECM connector for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
Check the harness and wiring for abrasion and for pinch points from the engine speed/timing sensors to the ECM. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The harness and the wiring appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals for the connectors are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.STOPTest Step 2. Check for Active Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Restore the electrical power to the ECM.
Start the engine and run the engine. The problem may occur when the engine is at any operating temperature. However, the problem is more likely to occur when the engine is at the normal operating temperature.
If the engine will not start, monitor the engine speed on Cat ET while the engine is being cranked. Cat ET may need to be powered from another battery while the engine is being cranked. This is done so that Cat ET will not reset. Note: Upon initial cranking, the status for engine speed may indicate that the engine speed signal is abnormal. This message should be replaced with an engine speed once the ECM is able to calculate a speed from the signal.
Check for one of the following logged diagnostic codes or active diagnostic codes:
190-08 Engine Speed signal abnormal
342-08 Secondary Engine Speed signal abnormalExpected Result:One of the above codes are active or logged.Results:
No engine rpm - Engine rpm is not indicated on Cat ET. Proceed to Test Step 3.
Active or logged code - There is an active diagnostic code or a logged diagnostic code for an engine speed/timing sensor. Proceed to Test Step 4.
No codes - Neither code is active or logged.Repair: Refer to the appropriate symptoms in Troubleshooting, "Troubleshooting Without a Diagnostic Code".STOPTest Step 3. Check the Installation of the Sensor Assembly
Remove the electrical power from the ECM.
Illustration 5 g01434702
Sensor installation
(4) Mounting surface
(5) Flange
(6) Bracket
Visually inspect the sensors without removing the sensor assembly from the engine. Flange (5) must be flush against mounting surface (4) in order to ensure proper operation. Inspect bracket (6). Verify that the bracket securely holds the flange of the sensor flush against the mounting surface.Verify that the bracket is not bent. If the bracket is bent or if an obstruction is preventing the sensor assembly from being installed correctly, the engine will not start.Note: The bracket cannot be replaced