844966 Volvo.Penta Fuel pipe

Illustration 1 g00815394
Typical schematic
Table 1
Correlation Between Throttle Switch Position and Status of the Throttle Inputs    
Throttle Switch Position    Desired Engine Speed    Status on ET    
"Throttle Input #1" "Throttle Input #2"    "Throttle Input #3"    "Throttle Input #4"    
1     725     On     Off     Off     Off    
2     840     On     On     Off     Off    
3     970     Off     On     Off     Off    
4     1100     Off     On     On     Off    
5     1230     On     On     On     Off    
6     1360     On     Off     On     Off    
7     1490     Off     Off     On     Off    
8     1620     Off     Off     On     On    
9     1750     On     Off     On     On    
10     1830     On     On     On     On    Test Step 1. Inspect Electrical Connectors and Wiring.
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect ECM connector J1/P1, machine connector J3/P3, and the throttle switch connector J118/P118. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.
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 should be completely inserted and coupled. The harness and wiring should be free of corrosion, abrasion, and pinch points.Results:
OK - All connectors, pins, and sockets are completely inserted and coupled. The harness and wiring are free of corrosion, abrasion, and pinch points. Proceed to Test Step 2.
Not OK - All connectors, pins, and sockets are not completely inserted and coupled. The harness and wiring are not free of corrosion, abrasion, and pinch points.Repair: Repair the circuit.Verify that the repair eliminates the problem. Stop.Test Step 2. Check the "Throttle Cab Switch Position" on ET.
Connect ET at the service tool connector.
Turn the keyswitch to the ON position.
Observe the status of the throttle switch and the throttle inputs on ET while you operate the throttle switch in each position.Expected Result:The status on ET should correspond with the information in Table 1.Results:
OK - The throttle switch is functioning properly at this time.Repair: Refer to Troubleshooting, "Inspecting Electrical Connectors" if the problem is intermittent. Stop.
Not OK - Record the suspect input. Proceed to Test Step 3.Test Step 3. Jumper the Switch Input at the Throttle Switch Connector.
Disconnect the throttle switch connector J118/P118.
Observe the status of the suspect throttle input on ET.
Use a suitable piece of wire to short P118-1 (Digital Return) to the terminal for the suspect throttle input at the throttle switch connector P118.
Observe the status of the suspect throttle input on ET.
Remove the wire short.Expected Result:The status of the suspect throttle input should be "Off" when the throttle switch connector J118/P118 is disconnected. The status should be "On" when the wire short is installed.Results:
OK - The harness and the ECM are okay.Repair: Replace the throttle switch.Verify that the repair eliminates the problem. Stop.
Not OK - The ECM did not get the correct signal. There is a problem in the harness. Proceed to Test Step 4.Test Step 4. Check for Shorts in the Harness.
Turn the keyswitch to the OFF/RESET position.
Disconnect ECM connector J1/P1 and the throttle switch connector J118/P118.
Measure the resistance between engine ground and the terminal for the suspect throttle input at the throttle switch connector P118.
Measure the resistance between the terminal for the suspect throttle input at the throttle switch connector P118 and the remaining terminals at the connector.Expected Result:The resistance should be greater than 20,000 Ohms for each reading.Results:
OK - The resistance is greater than 20,000 Ohms for each reading. Proceed to Test Step 5.
Not OK - The resistance is less than 20,000 Ohms for each reading. 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 the Resistance through the Harness.
Use a suitable piece of wire to short P118-1 (Digital Return) to the terminal of the suspect throttle input at the throttle switch connector P118.
Measure the resistance between P1-29 (Digital Return) and the terminal for the suspect throttle input at ECM connector P1.Expected Result:The resistance should be less than 10 Ohms.Results:
OK - The resistance is less than 10 Ohms. Proceed to Test Step 6.
Not OK - The resistance is greater than 10 Ohms. There is an open circuit or excessive r