SEAL 1552592 - Caterpillar

System Operation Description:The Engine Speed/Timing Sensor provides engine information to the Electronic Control Module (ECM). The sensor generates a pulse signal. A loss of the engine speed/timing signal causes the ECM to stop sending power to the fuel injectors.The ECM provides the Engine Speed/Timing Sensor with 12.5 1.0 VDC. A unique tooth on the timing reference gear generates a unique duty cycle. The signal provides the ECM with information on the engine position.
Illustration 1 g00594171
SchematicTest Step 1. Check for Connector Damage.
Turn the ECS to the OFF/RESET position.
Check the connectors and wiring for the following problems: damage, corrosion, abrasion and incorrect attachment.Expected Result:The connectors and wiring are free of the following problems: damage, corrosion, abrasion and incorrect attachment.Results:
OK - Proceed to test step 2.
Not OK - Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring. Stop.Test Step 2. Check for a CID-FMI.
Connect the ET.
Turn the ECS to the ON position. The engine should be OFF.
Access the logged diagnostic codes on the ET.Expected Result:The ET indicates a CID-FMI 190-03.Results:
OK - The 190-03 CID-FMI is present. Proceed to test step 3.
Not OK - Proceed to test step 4.Test Step 3. Check for Shorts in the Harness.
Turn the ECS to the OFF/RESET position.
Disconnect connectors J1/P1 and J20/P20.
Measure the resistance between J20-A (996-GN) and J20-B (998-BR).
Measure the resistance between J20-A (996-GN) and J20-C (999-WH).
Measure the resistance between J20-B (998-BR) and J20-C (999-WH).
Measure the resistance from the following points to engine ground: J20-A, J20-B and J20-C.Expected Result:Resistance should be more than 20,000 Ohms.Results:
OK - Proceed to test step 5.
Not OK - There is a short circuit in the harness or the connectors.Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring. Stop.Test Step 4. Check the Sensor.
Be sure to extend the sliphead before you install the Engine Speed/Timing Sensor. Also check that the Timing Gear is in a position that will not allow the sliphead of the Engine Speed/Timing Sensor to protrude into one of the slots of the Timing Gear. This is done visually with a flashlight prior to the installation of the Engine Speed/Timing Sensor. Turn the crankshaft to rotate the Timing Gear, if necessary, to position the gear in a place that will not allow the sliphead to protrude into a slot. If the sensor sliphead does protrude into one of the slots, the sliphead will be broken off as the gear begins to rotate.
Disconnect J20/P20 and remove the Engine Speed/Timing Sensor.
Inspect the plastic sliphead for damage.
Check the tension. Gently extend the sliphead 3.5 mm (0.14 inch). Return the sliphead to the original position.
Extend the sliphead.
Install the Engine Speed/Timing Sensor.Expected Result:The sliphead should take at least 22 N (5 lb) of force to push in the sliphead from the extended position.Results:
OK - The sensor and the sliphead are undamaged. The tension on the sliphead is normal. Reinstall the sensor. Proceed to test step 6.
Not OK - The Engine Speed/Timing Sensor or the sliphead is damaged and/or the sliphead has insufficient tension.Repair: Replace the Engine Speed/Timing Sensor.