843659 Volvo.Penta Tube

Illustration 1 g00712704
Schematic
Table 1
Correlation Between Throttle Switch Position and Status of the Throttle Inputs    
Throttle Switch Position    Status on ET    
"Throttle Input #1" "Throttle Input #2"    "Throttle Input #3"    "Throttle Input #4"    
Center     Off     On     Off     On    
Low Idle     On     On     Off     Off    
High Idle     Off     Off     On     On    Test Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect the J1/P1 ECM connector, the J3/P3 machine connector, and the throttle switch connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the sensor connectors that are associated with the active diagnostic code.
Check the ECM connector (allen head screw) for the proper torque of 6.0 N m (55 lb in).
Check the harness and wiring for corrosion, abrasion, and pinch points from the throttle switch to the ECM.Expected Result:All connectors, pins, and sockets are completely inserted and coupled. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The harness and wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem with the harness and/or wiring.Repair: Repair the circuit.Verify that the repair eliminates the problem. Stop.Test Step 2. Check the Status on the Electronic Service Tool
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position.
Observe the status of the throttle switch and the throttle inputs on Cat ET while you operate the throttle switch in each position.Expected Result:The status on Cat ET corresponds with the information in Table 1.Results:
OK - The status information is correct. The throttle switch is functioning properly at this time.Repair: Refer to Troubleshooting, "Electrical Connectors - Inspect" if the problem is intermittent. Stop.
Not OK - The status information is not correct. Record the suspect input. Proceed to Test Step 3.Test Step 3. Jumper the Switch Input at the Throttle Switch Connector
Turn the keyswitch to the OFF/RESET position.
Disconnect the throttle switch.
Turn the keyswitch to the ON position.
Observe the status of the suspect throttle input on Cat ET.
Use a suitable piece of wire to short terminal 2 (Digital Return) to the terminal for the suspect throttle input at the throttle switch connector.
Observe the status of the suspect throttle input on Cat ET.
Move the wire short from terminal 2 (Digital Return) to terminal 5 (Digital Return) of the throttle switch connector.
Observe the status of the suspect throttle input on Cat ET.
Remove the wire short.Expected Result:The status of the suspect throttle input is "Off" when the throttle switch connector is disconnected. The status is "On" when the wire short is installed. The status does not change when the wire short is moved from terminal 2 to terminal 5.Results:
OK - The status of the suspect throttle switch is acceptable. The harness and the ECM are OK.Repair: Replace the throttle switch.Verify that the repair eliminates the problem. Stop.
Not OK - The status of the suspect throttle switch is not acceptable. Proceed to Test Step 4.Test Step 4. Check for Shorts in the Harness
Turn the keyswitch to the OFF/RESET position.
Disconnect the J1/P1 ECM connector and the throttle switch connector.
Measure the resistance between engine ground and the terminal for the suspect throttle input at the throttle switch connector.
Measure the resistance between the terminal for the suspect throttle input and the remaining terminals at the throttle switch connector.Expected Result:Resistance is greater than 20,000 for each reading.Results:
OK - The resistance is acceptable. Proceed to Test Step 5.
Not OK - The resistance is not acceptable. There is a short in the harness between the ECM and the throttle switch.Repair: Repair the circuit.Verify that the repair eliminates the problem. Stop.Test Step 5. Check Resistance through the Harness
Illustration 2 g00936775
P1 ECM connector (ECM side)
Use a suitable piece of wire to short terminal 5 (Digital Return) to the terminal of the suspect throttle input at the throttle switch connector.
Measure the resistance between P1:29 (Digital Return) and the terminal for the suspect throttle input at ECM connector P1.Expected Result:Resistance is less than 10 Ohms.Results:
OK - The resistance is acceptable. Proceed to Test Step 6.
Not OK - The resistance is not acceptable. There is an open circuit or excessive resistance in the harness.Repair: Repair the circuit.Verify that the repair eliminates the problem. Stop.Test Step 6. Check the Harness and the ECM