3512B Oil Well Servicing Engine (ADEM III) Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with the air shutoff system or if any one of the diagnostic codes in Table 1 is active or easily repeated.

The ECM has the ability to stop the engine by shutting off the air supply in an emergency situation. The ECM activates the air shutoff solenoid which activates the air inlet shutoff valve.

The first condition occurs when the operator initiates an emergency shutdown. When the shutdown is recognized, fuel is shut off and the air shutoff solenoid is activated. The second condition is for an engine overspeed.

The customer can activate the air shutoff solenoid by supplying 24 VDC to terminal 04 of the customer connector.

Regardless of the reason for activation, the main power to the ECM must be turned OFF for three seconds in order to reset the engine control.

Note: The air shutoff is optional. A programmable parameter needs to be set with Caterpillar Electronic Technician (ET) in order to enable the air shutoff.

Note: Ensure that the air shutoffs are manually reset after an emergency stop in order to start the engine again.

Illustration 1	g01227331
Typical schematic for the air shutoff system

Test Step 1. Inspect the Electrical Connectors and the Wiring

1. Remove electrical power from the ECM.
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   Illustration 2	g01227322
   Location of the components for the air shutoff system (typical left side engine view) (1) Air shutoff solenoids (2) Customer connector (3) J1/P1 ECM connector (4) J2/P2 ECM connector

2. Thoroughly inspect the connections at solenoids (1). Also, thoroughly inspect connectors (2), (3), and (4). Inspect all of the connectors that are associated with the circuit.

   Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.

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   Illustration 3	g01227424
   P1 ECM connector (P1-5) Digital return (P1-21) Start/Run/Stop input 1 (P1-22) Start/Run/Stop input 2 (P1-23) Emergency stop signal "C" (P1-28) Emergency stop signal "D" (P1-52) +Battery (P1-53) +Battery (P1-55) +Battery (ECM) (P1-56) Air shutoff (N/O) (P1-63) −Battery (P1-65) −Battery (P1-70) Keyswitch

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   Illustration 4	g01227426
   P2 ECM connector (P2-13) Air shutoff

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   Illustration 5	g01227669
   Customer connector (Terminal 01) +Battery (Terminal 02) +Battery (Terminal 04) Air shutoff (Terminal 09) Digital return (Terminal 16) Emergency stop signal "D" (Terminal 17) Emergency stop signal "C" (Terminal 23) Start/Run/Stop input 1 (Terminal 24) Start/Run/Stop input 2 (Terminal 27) Keyswitch (Terminal 34) −Battery (Terminal 35) −Battery

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

4. Check the allen head screw for each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Inspecting Electrical Connectors" for the correct torque values.

5. Check the harness and wiring for abrasion and for pinch points from the sensors back to the ECM.

Expected Result:

All 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.

  Repair: The problem may be intermittent. If the problem is intermittent, refer to Troubleshooting, "Inspecting Electrical Connectors".

  STOP

• Not OK - There is a problem with the connectors and/or wiring.

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

  STOP

Test Step 2. Check for Active Diagnostic Codes

1. Remove electrical power from the ECM.

2. Connect Cat ET to the service tool connector.

3. Restore electrical power to the ECM.

4. Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes for the air shutoff system.

   Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

Expected Result:

No diagnostic codes are active.

Results:

• OK - No diagnostic codes are active.

  Repair: The problem may be intermittent. If the problem is intermittent, refer to Troubleshooting, "Inspecting Electrical Connectors".

  STOP

• Not OK - A -6 diagnostic code is active at this time. Proceed to Test Step 3.

• Not OK - A -5 diagnostic code is active at this time. Proceed to Test Step 4.

Test Step 3. Create an Open at the Connector for the Air Shutoff Solenoid

1. Remove electrical power from the ECM.

2. Disconnect the connector for the air shutoff solenoid.

3. Restore electrical power to the ECM.

4. Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes for the air shutoff system.

   Note: Wait at least 30 seconds in order for the diagnostic code to become active.

5. Check for a -5 diagnostic code.

6. Remove electrical power from the ECM.

Expected Result:

A -6 diagnostic code was active when the solenoid was connected to the circuit. A -5 diagnostic code is active when the solenoid is removed from the circuit.

Results:

• OK - A -6 diagnostic code was active before disconnecting the connector. A -5 diagnostic code became active after disconnecting the connector. The harness and the ECM are OK. The problem may be in the air shutoff solenoid.

  Repair: Temporarily connect a new air shutoff solenoid to the harness, but do not install the new air shutoff solenoid. Verify that there are no active diagnostic codes for the air shutoff solenoid. If there are no active diagnostic codes for the air shutoff solenoid, permanently install the new air shutoff solenoid. Clear any logged diagnostic codes.

  STOP

• Not OK - A -6 diagnostic code remains active. There is a short between the connector for the air shutoff solenoid and the ECM. Leave the connector for the air shutoff solenoid disconnected. Proceed to Test Step 5.

Test Step 4. Create a Short at the Connector for the Air Shutoff Solenoid

1. Remove electrical power from the ECM.

2. Disconnect the connector for the air shutoff solenoid.

3. Install a jumper wire between the terminals of the connector for the air shutoff solenoid.

4. Restore electrical power to the ECM.

5. Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes for the air shutoff system.

   Note: Wait at least 30 seconds in order for the diagnostic code to become active.

6. Check for a -6 diagnostic code.

7. Remove electrical power from the ECM.

Expected Result:

A -6 diagnostic code is active when the jumper wire is installed. A -5 diagnostic code is active when the jumper wire is removed.

Results:

• OK - A -6 diagnostic code is active when the jumper wire is installed. A -5 diagnostic code is active when the jumper wire is removed. The engine harness and the ECM are OK.

  Repair: Temporarily connect a new air shutoff solenoid to the harness, but do not install the new air shutoff solenoid. Verify that there are no active diagnostic codes for the air shutoff solenoid. If there are no active diagnostic codes for the air shutoff solenoid, permanently install the new air shutoff solenoid. Clear any logged diagnostic codes.

  STOP

• Not OK - The -5 diagnostic code remains active with the jumper in place. The open circuit is between the ECM and the connector for the air shutoff solenoid. Proceed to Test Step 5.

Test Step 5. Test the Operation of the ECM

1. Remove electrical power from the ECM.

2. Fabricate jumper wires that can be used to replace the wires in the ECM connector for the air shutoff solenoid. Crimp a connector socket to one end of the jumper wires.

3. Disconnect the appropriate ECM connectors for the air shutoff solenoid.

4. Remove the wires for the air shutoff solenoid from the ECM connector.

5. Install the jumper wires into the terminal locations for the air shutoff solenoid at the ECM connector.

6. Connect the ECM connectors.

7. Check the operation of the ECM by creating an open at the ECM:

   1. Hold the loose end of the jumper wires away from any components in order to create an open circuit condition.

   2. Restore electrical power to the ECM.

   3. Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes for the air shutoff system.

      Note: Wait at least 30 seconds in order for the diagnostic code to become active.

   4. Remove electrical power from the ECM.

8. Check the operation of the ECM by creating a short circuit at the ECM:

   1. Create a short between the jumper wires at the ECM connector.

   2. Restore electrical power to the ECM.

   3. Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes for the air shutoff system.

      Note: Wait at least 30 seconds in order for the diagnostic code to become active.

   4. Remove electrical power from the ECM.

9. Reconnect all wires to the original configuration.

Expected Result:

A -5 diagnostic code is active when the wires from the air shutoff solenoid are open at the ECM connector. A -6 diagnostic code is active if the wires from the air shutoff solenoid are shorted at the ECM connector.

Results:

• OK - The ECM is operating properly. The problem is in the wiring between the ECM and the connector for the air shutoff solenoid.

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

  STOP

• Not OK - One of the following conditions exists: The -5 diagnostic code is not active when the wire for the prelube relay is disconnected. The -6 diagnostic code is not active when the wire jumper is installed.

  Repair: Replace the ECM. Refer to Troubleshooting, "Replacing the ECM". Verify that the problem is resolved.

  STOP