MAST 3C8036 - Caterpillar

Visually inspect each sensor assembly without removing the sensor assembly from the engine. Ensure that flange (1) is installed squarely against surface (2) .
Remove the suspect sensor assembly from the engine.
Illustration 3 g01167704
Typical engine speed/timing sensor (3) O-ring
Ensure that one O-ring (3) is installed on the sensor. Check the O-ring for damage. Replace the O-ring, if necessary.Results:
OK - The sensor's components are OK.Repair: Perform the following procedure in order to properly install the sensor assembly:
Lubricate the O-ring with engine oil.
Fully seat the sensor assembly in the engine.Note: If the sensor assembly will not fully seat into the engine, replace the sensor assembly.
Tighten the bracket bolt.
Connect the sensor's electrical connectors. Verify that the connectors are latched on both sides.
Ensure that the harness is properly secured, and that the tie-wraps are placed in the correct location. Proceed to Test Step 3.
Not OK - At least one of the sensor assembly's components is not OK.Repair: Obtain a new sensor assembly. Perform the following procedure in order to properly install the sensor assembly:
Lubricate each O-ring with engine oil.
Fully seat the sensor assembly in the engine.Note: If the sensor assembly will not fully seat into the engine, replace the sensor assembly.
Tighten the bracket bolt.
Connect the sensor's electrical connectors. Verify that the connector is latched.
Ensure that the harness is properly secured, and that the tie-wraps are placed in the correct location.Verify that the problem is resolved.STOPTest Step 3. Inspect the Electrical Connectors and the Wiring
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Location of the engine speed/timing sensors (typical front engine view) (4) Harness connectors for the secondary engine speed/timing sensor (5) Harness connectors for the primary engine speed/timing sensor
Illustration 5 g01167873
(6) J2/P2 ECM connector
Thoroughly inspect connectors (4), (5), and (6). Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 6 g01212538
P2 terminals that are associated with the engine speed/timing sensors (P2-25) Primary engine speed/timing − (P2-35) Primary engine speed/timing + (P2-46) Secondary engine speed/timing + (P2-47) Secondary engine speed/timing − (P2-92) Speed/timing shield
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the engine speed/timing sensors.
Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and the wiring for abrasion and for pinch points from each sensor back to the ECM.Expected Result:All of the connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The harness and connectors appear to be OK. Proceed to Test Step 4.
Not OK - The connectors and/or wiring are not OK.Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. 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 4. Measure the Sensor Resistance through the Engine Harness
Disconnect the J2/P2 ECM connectors.
If you are troubleshooting a problem with the primary engine speed/timing sensor, perform the following procedure:
Measure the sensor's resistance between P2-25 (primary