3500B Engines for Caterpillar Built Power Modules with the ADEM 2 Electronic Control Module Caterpillar

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
Schematic

Test Step 1. Check for Connector Damage.

1. Turn the ECS to the OFF/RESET position.

2. 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.

1. Connect the ET.

2. Turn the ECS to the ON position. The engine should be OFF.

3. 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.

1. Turn the ECS to the OFF/RESET position.

2. Disconnect connectors J1/P1 and J20/P20.

3. Measure the resistance between J20-A (996-GN) and J20-B (998-BR).

4. Measure the resistance between J20-A (996-GN) and J20-C (999-WH).

5. Measure the resistance between J20-B (998-BR) and J20-C (999-WH).

6. 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.

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NOTICE
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.

1. Disconnect J20/P20 and remove the Engine Speed/Timing Sensor.

2. Inspect the plastic sliphead for damage.

3. Check the tension. Gently extend the sliphead 3.5 mm (0.14 inch). Return the sliphead to the original position.

4. Extend the sliphead.

5. 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. Calibrate the sensor. Refer to Troubleshooting, "Engine Speed/Timing Sensor - Calibrate".

  Stop.

Test Step 5. Check the Resistance Through the Harness.

1. Use a suitable piece of wire to short J20-A (996-GN) to J20-B (998-BR).

2. Measure the resistance from P1-32 (996-GN) and P1-29 (998-BR).

3. Use a suitable piece of wire to short J20-A (996-GN) to J20-C (999-WH).

4. Measure the resistance between P1-32 (996-GN) and P1-38 (999-WH).

5. Remove all shorts and reconnect J1/P1 and J20/P20.

Expected Result:

Resistance should be less than 10 Ohms through the wires.

Results:

• OK - Harness resistance is within acceptable limits. Proceed to test step 7.

• Not OK - There is an open circuit or excessive resistance in the harness or connectors.

  Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

Test Step 6. Check RPM.

1. Connect the ET to the service tool connector.

2. Turn the ECS to the ON position. Start the engine, when possible.

3. Crank the engine. Observe the display on the ET.

Expected Result:

The ET should display a steady engine speed between 100 and 250 RPM while the engine is cranking.

Results:

• OK - The Engine Speed/Timing Sensor is operating normally at this time. Stop.

• Not OK - The ET does not display a correct engine RPM signal. Proceed to test step 8.

• The Engine Will Not Start. - The engine will not start, but engine speed appears on the ET.

  Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

Test Step 7. Check RPM.

1. Turn the ECS to the ON position. The engine should be OFF.

2. Crank the engine. Observe the display on the ET.

Expected Result:

The ET should display a steady engine speed between 100 and 250 RPM while the engine is cranking.

Results:

• OK - The Engine Speed/Timing Sensor is operating normally at this time. Stop.

• Not OK - Proceed to test step 9.

Test Step 8. Check the Voltage at the Sensor.

1. Turn the ECS to the ON position. The engine should be OFF.

2. Measure the voltage between P20-A and P20-B.

Expected Result:

The supply voltage should be 12.5 ± 1.0 VDC.

Results:

• OK - The sensor is receiving correct supply voltage. Proceed to test step 10.

• Not OK - Proceed to test step 11.

Test Step 9. Check the Signal Voltage at the ECM.

1. Turn the ECS to the ON position. The engine should be OFF.

2. Measure the voltage between P1-38 (999-WH) and P1-29 (998-BR).

3. Crank the engine and measure the voltage between P1-38 (999-WH) and P1-29 (998-BR).

4. Turn the ECS to the OFF/RESET position.

Expected Result:

With the ECS in the ON position, the voltage should measure less than 3 VDC. The voltage should measure more than 10 VDC with the ECS in the ON position. While the engine is cranking, the voltage should be 2.0 to 4.0 VDC.

Results:

• OK - A correct voltage appears at ECM connector P1 but the ECM is not reading the signal.

  Repair: Replace the ECM. Refer to Troubleshooting, "Replacing the ECM".

  Stop.

• Not OK - There is an intermittent problem in the Speed/Timing circuit.

  Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

Test Step 10. Check the Voltage at the Sensor.

1. Reconnect all connectors.

2. Remove the wire J20-C from the sensor connector.

3. Reconnect J20/P20.

4. Measure the voltage between P20-C and P20-B. Crank the engine and measure the voltage between P20-C and P20-B.

5. Turn the ECS to the OFF/RESET position.

6. Reinsert the sensor signal wire back into J20-C.

Expected Result:

With the ECS in the ON position, the voltage should measure less than 3 VDC and more than 10 VDC. While the engine is cranking, the voltage should be 2.0 to 4.0 VDC.

Results:

• OK - The Engine Speed/Timing Sensor is producing an output signal. Proceed to test step 3.

• Not OK -

  Repair: Replace the Engine Speed/Timing Sensor. Calibrate the sensor. Refer to Troubleshooting, "Engine Speed/Timing Sensor - Calibrate".

  Stop.

Test Step 11. Check Supply Voltage at Harness Side of Sensor Connector.

1. Measure the voltage between J20-A (996-GN) and J20-B (998-BR).

Expected Result:

The supply voltage should be 12.5 ± 1.0 VDC.

Results:

• OK - There is an open circuit or excessive resistance in J20/P20.

  Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

• Not OK - Proceed to test step 12.

Test Step 12. Check the Voltage at the ECM.

1. Measure the voltage between P1-32 (996-GN) and P1-29 (998-BR).

2. Turn the ECS to the OFF/RESET position.

Expected Result:

The voltage should be 12.5 ± 1.0 VDC.

Results:

• OK - There is an open circuit or excessive resistance.

  Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

• Not OK - Proceed to test step 14.

Test Step 13. Perform the following test: Engine Speed/Timing Sensor - Calibrate

Results:

• REPAIRED, OK - Stop.

• OK - Stop.

Test Step 14. Perform the following test: Electrical Power Supply

Results:

• REPAIRED, OK - Stop.

• OK - Stop.