TRANSFORMER AS-CURRENT 1179724 - Caterpillar

Assembly
A. Remove the electrical power from the ECM.
B. Visually inspect the sensors without removing the sensor assembly from the engine. Flange (2) must be flush against mounting surface (1) in order to ensure proper operation. Inspect bracket (3). 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 separately.
C. Remove the suspect engine speed/timing sensor from the engine.
D. Ensure that O-ring seals (7) are installed on sensors (5) and (9), and on mounting plate (6). Ensure that the O-ring seals are free of damage.
All of the O-ring seals are properly installed and free of damage. The bracket is free of damage.
Result: The O-ring seals are properly installed. The bracket and the seals are free of damage.
Repair: Perform the following procedure in order to install a sensor assembly:
1. Lubricate the O-ring seals with oil.
2. Fully seat each sensor into the housing.
Note: If the sensor assembly will not fully seat into the engine, replace the sensor assembly.
3. Tighten the bolt for brackets (4) and (8).
4. Connect the connector and verify that the latch tab of the connector is securely latched.
5. Ensure that the harness is properly secured, and that the tie-wraps are placed in the correct location.
Proceed to Test Step 3.
Result: At least one of the sensor assembly components is not OK.
Repair: Obtain a new sensor assembly. Perform the following procedure in order to install the sensor assembly:
Note: Do not switch the positions of the sensors. The sensors are not interchangeable. A timing calibration is not required when the sensors are replaced.
1. Lubricate each O-ring with oil.
2. Fully seat the sensor into the housing.
3. Tighten the bracket bolt.
4. Connect the connector and verify that the latch tab of the connector is securely latched.
5. Ensure that the harness is properly secured, and that the tie-wraps are placed in the correct location. Verify that the problem is resolved.
STOP
Illustration 5 g01375783
Front engine view
(10) Secondary speed/timing sensor
(11) Primary speed/timing sensor
Illustration 6 g01375821
Rear engine view
(12) P2 ECM connector
Illustration 7 g01237789
Terminal locations at the P2 ECM connector that are for the engine speed/timing sensors
(P2-25) Primary engine speed/timing signal (−)
(P2-35) Primary engine speed/timing signal (+)
(P2-46) Secondary engine speed/timing signal (+)
(P2-47) Secondary engine speed/timing signal (−)
Illustration 8 g01155187
Connector for the engine speed/timing sensors
(Terminal 1) Speed/timing sensor (−)
(Terminal 2) Speed/timing sensor (+)
Table 4
Troubleshooting Test Steps Expected Result Results
3. Inspect the Electrical Connectors and the Wiring
A. Remove the electrical power from the ECM.
B. Thoroughly inspect connectors (10), (11), and (12). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. 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.
D. Check the allen head screw for each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect".
E. Check the harness and wiring for abrasion and for pinch