849526 Volvo.Penta Tachometer

Illustration 1 g00840995
Typical schematic
Illustration 2 g01074524
P1 ECM connector (P1-17) Fuel filter differential pressure switch (P1-29) Digital returnTest Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF position.
Thoroughly inspect the ECM connectors J1/P1. Inspect the connector for the fuel filter differential pressure switch. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque of 6.0 N m (55 lb in).
Check the customer connector (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
Check the harness and the wiring for abrasion and for pinch points.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. 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 in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring.STOPTest Step 2. Check the Status of the Fuel Filter Differential Pressure Switch on the Caterpillar Electronic Technician (ET)
Disconnect connector J106/P106.
Use a suitable piece of wire to short P106-1 and P106-2 together.
Connect Cat ET to the cab service tool connector J42. Start Cat ET.
Turn the keyswitch to the ON position.
Observe the status of the fuel filter differential pressure switch on Cat ET.
Remove the wire short.
Observe the status of the fuel filter differential pressure switch on Cat ET.
Turn the keyswitch to the OFF position.Expected Result:The status of the fuel filter differential pressure switch is "NORMAL" when the short is installed. The status of the fuel filter differential pressure switch is "HIGH" when the wire is removed.Results:
OK - The status of the fuel filter differential pressure switch is "NORMAL" when the short is installed. The status of the fuel filter differential pressure switch is "HIGH" when the wire is removed. The status of the fuel filter differential pressure switch is correct.Repair: Replace the fuel filter. If the problem is not resolved, replace the fuel filter differential pressure switch. Verify that the fuel filter differential pressure switch solves the problem before you permanently install the new fuel filter differential pressure switch.STOP
Not OK - The status of the fuel filter differential pressure switch is not "NORMAL" when the short is installed. The status of the fuel filter differential pressure switch is not "HIGH" when the wire is removed. The status of the fuel filter differential pressure switch is not correct. There is a problem in the harness. Proceed to Test Step 3.Test Step 3. Check for a Short Circuit in the Wiring Harness
Disconnect ECM connector J1/P1.
Measure the resistance between P1-17 and every pin on ECM connector P1.
Measure the resistance between P1-17 and engine ground.
Measure the resistance between P1-29 and the engine ground.Expected Result:The resistance is greater than 20,000 Ohms.Results:
OK - The resistance is greater than 20,000 Ohms. Proceed to Test Step 4.
Not OK - The resistance is less than 20,000 Ohms. There is a short circuit in the wiring harness.Repair: Repair the connectors or wiring and/or replace the connectors or wiring.STOPTest Step 4. Check for an Open Circuit in the Harness
Use a wire to short P106-1 to P106-2 at the connector for the fuel filter differential pressure switch.
Measure the resistance between P1-17 and P1-29.Expected Result:The resistance is less than 5 Ohms.Results:
OK - The resistance is less than 5 Ohms. Proceed to Test Step 5.
Not OK - The resistance is greater than 5 Ohms. There is excessive resistance or an open circuit in the wiring harness.Repair: Repair the connectors or wiring and/or replace the connectors or wiring.STOPTest Step 5. Short the Fuel Filter Differential Pressure Switch at the ECM
Remove the wires P1-17 and P1-29 from ECM connector P1.
Insert a jumper wire with socket terminals on both ends at P1-17 and P1-29.
Reconnect the connector.
Turn the keyswitch to the ON position.Note: Additional diagnostic codes will be generated because the digital return will no longer be connected to other sensors and switches. Ignore the codes and clear the codes upon completing this test.
Observe the status of the fuel filter differential pressure switch on Cat ET.
Turn the keyswitch to the OFF position.
Disconnect ECM connector J1/P1.
Remove the wire short.
Reconnect ECM connector J1/P1.
Turn the keyswitch to the ON position.
Observe the status of the fuel filter differential pressure switch on Cat ET.
Reconnect all wires and connectors.Expected Result:The status of the fuel filter differential pressure switch is "NORMAL" when the short is installed. The status of the fuel filter differential pressure switch is "HIGH" when the wire is removed.Results:
OK - The status of the fuel filter differential pressure switch is "NORMAL" when the short is installed. The status of the fuel filter differential pressure switch is "HIGH" when the wire is removed. The ECM is OK.Repair: Reconnect all connectors and recheck the system. The problem may be intermittent. If the problem is intermittent, refer to Troubleshooting, "Inspecting Electrical Connectors".STOP
Not OK - The status of the fuel filter differential pressure switch is not "NORMAL" when the short is installed. The status of the fuel filter differential pressure switch is not "HIGH" when the wire is removed. The ECM is not reading the input from the fuel filter differential pressure switch correctly.Repair: Replace the ECM. Refer to Troubleshooting, "Replacing the ECM".STOP