System Operation Description:
Use this procedure under the following situation:
The engine running output circuit is suspected of incorrect operation.
The following background information is related to this procedure:
Engine Running Output
The “Engine Running Output” can be programmed to J1/P1:10, J1/P1:12, or J1/P1:13. The “Engine Running Output” will function on the following corresponding output that is selected:
• ECM Connector J1/P1:10
• ECM Connector J1/P1:12
• ECM Connector J1/P1:13
The “Engine Running Output” activates when the engine is running. This can be used to prevent the engagement of the starter motor while the engine is running. The ECM can be connected to a relay that disables the starter. The relay is normally closed so cranking can be achieved immediately at powerup. During cranking, the ECM energizes the “Engine Running Output” once engine rpm reaches 50 rpm below low idle. The output is de-energized when the engine speed falls by 100 rpm below the programmed low idle. The low idle rpm is programmable. The range for low idle is between 600 rpm and 750 rpm.
Test Step 1. Inspect Electrical Connectors and Wiring
A. Thoroughly inspect ECM vehicle harness connector J1/P1, and the firewall bulkhead connector. Refer to Troubleshooting, “Electrical Connectors – Inspect” for details.
B. Perform a 45 N (10 lb) pull test on terminal 10, terminal 12, or terminal 13 in the ECM connector. Refer to Illustration 92.
C. Check the ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).
D. Check the harness and wiring for abrasion and pinch points from the sensor to the ECM.
Expected Result:
All connectors, pins and sockets should be completely coupled and/or inserted and the harness and wiring should be free of corrosion, abrasion or pinch points.
Results:
• OK – Proceed to Test Step 2.
• Not OK – Repair the wiring or replace the wiring, if necessary. Repair the connectors or replace the connectors, if necessary. Ensure that all of the seals are in the proper place. Ensure that all of the connectors are connected properly. Verify that the repair eliminates the problem. STOP.
Test Step 2. Ensure Correct Parameter Programming
A. Connect the Caterpillar Electronic Technician (ET) to the cab data link connector.
B. Turn the ignition key switch to the ON position.
C. Access the customer specified parameter screen in order to make sure that the ECM is programmed to use the “Engine Running Output”.
D. Ensure that the “Engine Running Output” circuit is connected to the programmed output.
Expected Result:
The circuit is connected to the correct ECM terminal that is selected for the “Engine Running Output”.
Results:
• OK – Proceed to Test Step 3.
• Not OK – Update the customer specified parameter in order to match the correct output terminal. STOP.
Test Step 3. Use ET to Check the Relay
A. Turn the ignition key switch to the ON position.
B. Access the “Engine Running Output Special Test” on ET. The “Engine Running Output Special Test” will enable the “Engine Running Output” when the test is active.
C. Begin the “Engine Running Output Special Test” and listen for the relay to click. You may need to be near the engine in order to hear the click.
Expected Result:
The relay will activate when the special test is turned “On”.
Results:
• OK – The ECM and vehicle components are operating correctly. STOP.
• Not OK – Proceed to Test Step 4.
Test Step 4. Use ET to Check the ECM
A. Connect ET to the cab data link connector.
B. Turn the ignition key switch to the OFF position.
C. Disconnect the ECM vehicle harness connector J1/P1.
D. Connect a 70-Terminal Breakout T between ECM connectorsJ1 and P1.
E. If the “Engine Running Output” is programmed to J1/P1:10, connect a voltage test lamp to terminal 10 (Output 2) and terminal 65 (-Battery) of the breakout T.
F. If the “Engine Running Output” is programmed to J1/P1:12, connect a voltage test lamp to terminal 12 (Output 3) and terminal 65 (-Battery) of the breakout T.
G. If the “Engine Running Output” is programmed to J1/P1:13, connect a voltage test lamp to terminal 13 (Output 4) and terminal 65 (-Battery) of the breakout T.
H. Turn the ignition key switch to the ON position.
I. Access the appropriate “Engine Running Output Special Test” on ET.
J. Cycle the corresponding “Engine Running Output Special Test” to the ON position and to the OFF position and watch the voltage test lamp.
K. Stop the special test.
Note: A multimeter can not be used in place of the voltage test lamp when the ECM outputs are being tested.
Expected Result:
The voltage test lamp turns on when the“Engine Running Output Special Test” is active. The voltage test lamp also turns off when the “Engine Running Output Special Test” is not active.
Results:
• OK – The ECM is OK. The problem is in the vehicle wiring. Inspect the vehicle wiring and then repair the vehicle wiring. Otherwise, send the vehicle to the OEM dealer for repair. Verify that the original condition is resolved. STOP.
• Not OK – Temporarily connect a test ECM. Use the “Engine Running Output Special Test” on ET to check the ECM. If the problem is resolved with the test ECM, install the suspect ECM. If the problem returns with the suspect ECM, replace the ECM. Verify that the repair eliminates the problem. STOP.