PLUG-BUTTON 2547549 - Caterpillar

The Electronic Control Module (ECM) provides the engine speed/timing sensor with 12 1.0 VDC. The engine speed/timing sensor provides a pulse signal to the ECM. The signal is created as the timing reference gear rotates past the pickup of the engine speed/timing sensor. The timing reference gear is mounted on the rear of the left camshaft. A unique tooth pattern on the timing reference gear allows the ECM to determine the crankshaft position, rotation, and rpm.The engine speed/timing sensor generates a pulse signal to the ECM as each tooth passes the sensor. The ECM counts the pulses in order to determine the engine rpm. The ECM memorizes the pattern of the pulses. The ECM compares that pattern to a standard pattern in order to determine the crankshaft position. The ECM uses this information to determine the No. 1 cylinder. The ECM then triggers each fuel injector to fire in the correct firing order and at the correct time. The actual timing and duration of each injection is determined by the ECM. The ECM uses engine rpm and engine load to determine the timing and duration of injection. The loss of the signal from the engine speed/timing sensor generates a diagnostic code. The loss of the signal from the engine speed/timing sensor triggers the termination of the signals to the fuel injectors by the ECM.Note: If the engine timing gear is installed backward, the ECM will generate a diagnostic code. The diagnostic code that is generated will be 190-08 Engine Speed signal abnormal. If this code is active, the ECM will not fire the injectors.
Illustration 1 g01208740
Left side view
(1) Engine speed/timing sensor
Illustration 2 g01204148
Schematic
Illustration 3 g01156100
P1 ECM connector
(P1-5) Digital return
(P1-33) Engine speed/timing signal
(P1-40) Engine timing calibration -
(P1-41) Engine timing calibration +
(P1-43) +12 V supply Test Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors for the circuit. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.
Check the harness and the wiring for abrasion and for pinch points. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - The harness and connectors appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem with the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check for a "LOGGED" Diagnostic Code
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position.
Check the diagnostic codes on Cat ET. Expected Result:Cat ET indicates