3512B Petroleum Engines with the ADEM 2 Electronic Control Module Caterpillar

To reduce resistance in the wiring harness, there are two isolated power connections to the Electronic Control Module (ECM). The connections must be complete in order to ensure proper engine operation. There is a constant power supply to the ECM when the engine is shutdown. In order to shut off the power to the ECM, the main power needs to be disconnected.

The engine will begin the start-up when the following conditions exist:

• The ECM detects the battery voltage at the keyswitch on P1-23.

• The Start/Run/Stop Switches are activated.

An Emergency Stop Switch and a Start/Run/Stop Switch are provided by the customer.

The customer can install multiple Start/Run/Stop Switches and Emergency Stop Push Buttons.

When the Emergency Stop Push Button is activated, the digital reference is removed from the Emergency Stop input. The fuel supply to the injectors will be cut off and the air shutoff relays will be activated.

Note: The Emergency Stop Push Button is activated or ON when the button is pushed in. The Emergency Stop Push Button is deactivated or OFF when the button is pulled out.

Note: If welding occurs on the engine or near the engine, be sure to protect the engine electronics from spikes in the voltage. The engine block and the driven equipment should be properly grounded. This will prevent any electrical discharge across the main bearings.

Proper welding procedures are necessary to avoid damage to the electronic control module and associated sensors and components. The guidelines which are listed should be followed when you are welding on any engine or for any application that uses electronic controls. The guidelines for welding follow:

• Stop the engine. Put the start switch on the OFF position.

• Disconnect the ECM connectors, J1 and J2 from the harness.

• Disconnect the negative battery cable at the battery. If a battery disconnect switch is provided, put the switch in the OPEN position. Do not use fuel system components for grounding the welder.

• Connect the clamp for the ground cable of the welder directly to the part. Place this clamp as close as possible to the weld in order to reduce the possibility of damage by the welding current. Components which can be easily damaged include bearings, hydraulic components, and electrical components.

• Protect any wiring harness from welding debris and spatter.

• Use standard welding procedures in order to weld the materials.

Illustration 1	g00861631
Typical example

Test Step 1. Check for Connector Damage.

1. Turn the main disconnect switch to the OFF position.

2. Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.

3. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.

4. Check the ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).

5. Check the customer connector (allen head screw) for the proper torque of 2.25 ± 0.25 N·m (20 ± 2 lb in).

6. Check the harness and the wiring for abrasion and pinch points.

Expected Result:

The connectors and wiring are free of the following problems: damage, abrasion, corrosion and incorrect attachment.

Results:

• OK - The connectors and wiring are okay. Proceed to test step 2.

• Not OK - The connectors and/or wiring need repair.

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

  STOP

Test Step 2. Check for "ACTIVE" Diagnostic Codes

1. Start the Caterpillar Electronic Technician (ET).

2. Turn the main disconnect switch to the ON position.

3. Determine if you have either of the following active diagnostic codes:
   • CID-FMI 168-00 System Voltage High

   • CID-FMI 168-01 System Voltage Low

Expected Result:

One of the diagnostic codes is present.

Results:

• OK - One of the diagnostic codes is present. Proceed to test step 3.

• Not OK - One of the diagnostic codes is not present. Proceed to test step 4.

Test Step 3. Check the Battery Voltage.

1. Turn the main disconnect switch to the OFF position.

2. Measure no-load voltage at the battery posts. Refer to Testing and Adjusting, "Test Tools for the Electrical System" for the proper procedures to check the batteries.

3. Load test the batteries. Use the 4C-4911 Battery Load Tester. Refer to the Operating Manual, SEHS9249. Refer to Special Instruction, SEHS7633.

Expected Result:

The no-load voltage at the batteries should be at least 23.5 VDC, and the batteries should pass the load test.

Results:

• OK - The no-load voltage at the batteries is at least 23.5 VDC, and the batteries pass the load test. Proceed to test step 4.

• Not OK - The no-load voltage at the batteries is less than 23.5 VDC, and/or the batteries fail the load test.

  Repair: The batteries or the alternator are causing the problem. Recharge the batteries or replace the batteries. Verify that the original condition is resolved. Refer to Testing and Adjusting, "Electrical System".

  STOP

Test Step 4. Check for Supply Voltage to the ECM.

1. Turn the main disconnect switch to the OFF position.

2. Disconnect ECM connector J1/P1.

3. Turn the main disconnect switch to the ON position.

4. Measure the voltage at the ECM connector P1 between pins P1-04 and P1-11.

5. Measure the voltage at the ECM connector P1 between pins P1-06 and P1-05.

Expected Result:

The voltage should measure 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC. Proceed to test step 5.

• Not OK - The voltage does not measure 24 ± 3 VDC.

  Repair: There is a problem with the wiring and/or connectors between the battery and the ECM. Repair the connectors and/or wiring or replace the connectors and/or wiring.

  STOP

Test Step 5. Check the Voltage to the ECM from the Battery.

1. Measure the voltage at the ECM connector P1 between pins P1-23 and P1-11.

2. Turn the main disconnect switch to the OFF position.

3. Reconnect ECM connector J1/P1.

Expected Result:

The voltage should measure 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC. Proceed to test step 6.

• Not OK - The voltage does not measure 24 ± 3 VDC.

  Repair: Check for voltage at the Battery. There may be a problem with the wiring and/or connectors between the Battery and the ECM. Repair the connectors and/or wiring or replace the connectors and/or wiring.

  STOP

Test Step 6. Check the Voltage at the Emergency Stop Input to the ECM.

1. Turn the main disconnect switch to the ON position.

2. Connect a voltage test lamp at the ECM connector P1 between pins P1-20 and P1-29.

3. Connect a voltage test lamp at the ECM connector P1 between pins P1-02 and P1-29.

Expected Result:

The voltage test lamp should not illuminate.

Results:

• OK - The voltage test lamp did not illuminate. Proceed to test step 7.

• Not OK - The voltage test lamp illuminated.

  Repair: The Emergency Stop circuit has been activated or the emergency stop circuit has an open circuit. Verify that the Emergency Stop switches are not activated. Check the Emergency Stop switches for proper operation. There may be a problem in the wiring and/or connectors. Repair the connectors and/or wiring or replace the connectors and/or wiring.

  STOP

Test Step 7. Check the Voltage at the ECM from the Start/Run/Stop Switch.

1. Connect a voltage test lamp at the ECM connector P1 between pins P1-14 and P1-29.

2. Connect a voltage test lamp at the ECM connector P1 between pins P1-08 and P1-29.

3. Turn the Start/Run/Stop switch to the RUN position.

4. Monitor the voltage test lamp at the ECM connector P1 between pins P1-14 and P1-29.

5. Monitor the voltage test lamp at the ECM connector P1 between pins P1-08 and P1-29.

6. Turn the Start/Run/Stop switch to the STOP position.

Expected Result:

The voltage test lamp should be illuminated before the Start/Run/Stop switch is activated. The voltage should not be illuminated after the Start/Run/Stop switch is activated.

Results:

• OK - The Start/Run/Stop switch and the wiring to the ECM are okay.

  Repair: There may be an intermittent problem. If the problem is intermittent perform the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".

  STOP

• Not OK - No Voltage Present - The voltage test lamp does not illuminate before the Start/Run/Stop switch is activated. Proceed to test step 8.

• Not OK - No 0.0 VDC - The voltage test lamp illuminates after the Start/Run/Stop switch is activated.

  Repair: Check the voltage at the Start/Run/Stop switch. Voltage should not be present after the Start/Run/Stop switch is activated. The Start/Run/Stop switch may need to be replaced. Check for proper operation of the Start/Run/Stop switch. Check the wiring and the connectors between the Start/Run/Stop switch and the ECM. Repair the connectors and/or wiring or replace the connectors and/or wiring.

  STOP

Test Step 8. Check the Voltage at the ECM.

1. Turn the main disconnect switch to the OFF position.

2. Remove wire F717-YL on P1-14 from ECM connector P1. Install a wire jumper into the socket for P1-14.

3. Remove wire F716-WH on P1-08 from ECM connector P1. Install a wire jumper into the socket for P1-08.

4. Turn the main disconnect switch to the ON position.

5. Connect a voltage test lamp at the ECM connector P1 between the wire jumper in P1-14 and P1-29.

6. Connect a voltage test lamp at the ECM connector P1 between the wire jumper in P1-08 and P1-29.

7. Turn the main disconnect switch to the OFF position. Remove all wire jumpers and replace all wiring and connectors to the original configuration.

Expected Result:

The voltage test lamp should illuminate.

Results:

• OK - The voltage test lamp illuminates.

  Repair: There may be an intermittent problem. If the problem is intermittent, perform the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".

  STOP

• Not OK - The voltage test lamp does not illuminate.

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

  STOP