851940 Volvo.Penta Hex. socket screw

Illustration 1 g00735010
SchematicTest Step 1. Check for Connector Damage
Turn the keyswitch to the OFF/RESET position.
Check the J1/P1 ECM connector, J3/P3 machine connector, and the associated wiring for the following problems: damage, corrosion, abrasion and incorrect attachment. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.Expected Result:The connectors and wiring are free of the following problems: damage, corrosion, abrasion and incorrect attachment.Results:
OK - Proceed to test step 2.
Not OK - Repair: Repair the circuit.Verify that the repair eliminates the problem. Stop.Test Step 2. Check the Switch Status
Connect Cat ET to the service tool connector.
Turn the keyswitch to the ON position.
Operate the ground level shutdown switch.
Observe the status for "Shutdown Switch" on Cat ET.
Turn the keyswitch to the OFF/RESET position.Expected Result:The status of the switch reads "ON" with the switch in the STOP position. The status reads "OFF" with the switch in the RUN position.Results:
OK - The switch is operating normally.Repair: Refer to Troubleshooting, "Electrical Connectors - Inspect" if the problem is intermittent. Stop.
Not OK - Proceed to Test Step 3.Test Step 3. Short the Wires at the SwitchLabel the switch wiring before removing the wires.
Disconnect all of the wires from the ground level shutdown switch.
Use a suitable piece of wire to short F716-WH and 998-BR together.
Turn the keyswitch to the ON position.
Observe the status for "Shutdown Switch" on Cat ET.
Remove the wire short between F716-WH and 998-BR.
Use a suitable piece of wire to short F715-PU and 998-BR together.
Ensure that the keyswitch is in the ON position.
Observe the status for "Shutdown Switch" on Cat ET.
Remove the wire short.Expected Result:The status of the switch reads "OFF" when F716-WH and 998-BR are shorted together. The status for "Shutdown Switch" reads "ON" when F715-PU and 998-BR are shorted together.Results:
OK - The problem is not with the harness and/or the ECM.Repair: Temporarily connect a new switch. Verify that the new switch solves the problem before you permanently install the new switch. Stop.
Not OK - There is a problem in the harness and/or the ECM. Proceed to test step 4.Test Step 4. Check for a Short Circuit in the Wiring Harness
Illustration 2 g00938936
P1 ECM connector
Turn the keyswitch to the OFF/RESET position.
Disconnect the J1/P1 ECM connector and the wires at the ground level shutdown switch.
Measure the resistance between the following wires:
P1:2 (Ground Level Shutdown (NO)) to P1:29 (Digital Return)
P1:8 (Ground Level Shutdown (NC)) to P1:29 (Digital Return)
P1:2 (Ground Level Shutdown (NO)) to P1:8 (Ground Level Shutdown (NC))
P1:8 (Ground Level Shutdown (NC)) to engine ground
P1:2 (Ground Level Shutdown (NO)) to engine groundExpected Result:The resistance is greater than 20,000 Ohms for each measurement.Results:
OK - There are no shorts in the harness. Proceed to test step 5.
Not OK - There is a short circuit in the harness or connectors between the switch and the ECM.Repair: Repair the circuit.Verify that the repair eliminates the problem. Stop.Test Step 5. Check the Resistance Through the Harness
Illustration 3 g00735074
P1 ECM Connector (wire side)
Ensure that the J1/P1 ECM connector is disconnected, and ensure that the wires at the ground level shutdown switch are disconnected.
Short F715-PU and 998-BR together at the ground level shutdown switch.
Measure the resistance between P1:2 (Ground Level Shutdown (NO)) and P1:29 (Digital Return).
Remove the wire short.
Short F716-WH and 998-BR together at the ground level shutdown switch.
Measure the resistance between P1:8 (Ground Level Shutdown (NC)) and P1:29 (Digital Return).
Remove the wire short.Expected Result:The resistance is less than 10 Ohms for each measurement.Results:
OK - The resistance is within acceptable limits. Proceed to test step 6.
Not OK - There is an open or excessive resistance in the harness.Repair: Repair the harness.Verify that the repair eliminates the problem. Stop.Test Step 6. Short the Switch Inputs at the ECM
Illustration 4 g00735074
P1 ECM Connector (wire side)
Turn the keyswitch to the OFF position.
Disconnect the J1/P1 ECM connector.
Use a 121-9587 Wire Removal Tool to remove the following wires from the P1 ECM connector:
P1:2 (Ground Level Shutdown (NO))
P1:8 (Ground Level Shutdown (NC))
P1:29 (Digital Return)
Fabricate a jumper wire out of 18 AWG insulated wire with Deutsch socket terminals on each end.
Insert one end of the jumper wire into P1:8 (Ground Level Shutdown (NC)) on the P1 ECM connector and insert the other end into P1:29 (Digital Return) on the P1 ECM connector.
Reconnect the J1/P1 ECM connector.
Turn the keyswitch to the ON position.Note: Additional diagnostic codes will be generated because P1:29 (Digital Return) will no longer be connected to other sensors and switches. Clear the additional diagnostic codes upon completing this test.
Observe the status for "Shutdown Switch" on Cat ET.
Turn the keyswitch to the OFF/RESET position.
Disconnect the J1/P1 ECM connector and remove the jumper wire from P1:8 (Ground Level Shutdown (NC)). Leave the other end of the jumper wire in P1:29 (Digital Return).
Insert the loose end of the jumper wire into P1:2 (Ground Level Shutdown (NO)) on the P1 ECM connector.
Reconnect the J1/P1 ECM connector.
Turn the keyswitch to the ON position.
Observe the status for "Shutdown Switch" on Cat ET.