7008 Mercruiser DIODE TRIO

Illustration 1 g01459101
Schematic of the circuit for the fuel rail pump solenoid
Illustration 2 g01459102
Pin locations for the electrical power supply circuit on the P2 connector
(25) Fuel rail pump solenoid PWM signal
(26) Fuel rail pump solenoid return Test Step 1. Inspect the Electrical Connectors and the Harness
Electrical shock hazard. The fuel rail pump solenoid uses 63 to 73 volts.
Turn the keyswitch to the OFF position.
Thoroughly inspect the harness connector P2/J2 and the suspect connector P532. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the solenoid connector P532 and the connector pins 25 and 26 that are associated with the fuel rail pump solenoid. Refer to illustration 2.
Check the harness for abrasions and for pinch points from the battery to the ECM. Check the harness for abrasions and for pinch points from the key switch to the ECM.
Use the electronic service tool in order to perform a "Wiggle Test". The "Wiggle Test"is used to identify intermittent connections. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. The harness is free of corrosion, of abrasion, and of pinch points.Results:
OK - The connectors and the harness appear to be OK. Proceed to Test Step 2.
Not OK - There is a fault with the connectors and/or the harness.Repair: Repair the connectors or the harness and/or replace the connectors or the harness. Ensure that all of the seals are correctly in place and ensure that the connectors are completely coupled.Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair has eliminated the fault.STOPTest Step 2. Check for Active Diagnostic Codes
Connect the electronic service tool to the diagnostic connector.
Turn the keyswitch to the ON position.
Use the electronic service tool to verify if any of the following diagnostic codes are active or recently logged:
1779-05 Fuel Rail #1 Pressure Valve Solenoid current below normal
1779-06 Fuel Rail #1 Pressure Valve Solenoid current above normalExpected Result:One or more of the following diagnostic codes are active or recently logged:
1779-05 Fuel Rail #1 Pressure Valve Solenoid current below normal
1779-06 Fuel Rail #1 Pressure Valve Solenoid current above normalResults:
1779-05 - Proceed to Test Step 3.
1779-06 - Proceed to Test Step 7.
Not OK - No active diagnostic codes or recently logged diagnostic codes are displayed.STOPTest Step 3. Check the Harness for an Open Circuit
Turn the keyswitch to the OFF position.
Disconnect P2 from the ECM.
Measure the resistance between P2:25 and P2:26. Expected Result:The nominal resistance is less than 2.0 Ohms.Results:
OK - The harness and the solenoid do not have an open circuit.Repair: Check the high pressure fuel system for leaks. A mechanical relief valve is installed in the high pressure fuel rail. Check that there is no flow of fuel from the mechanical relief valve. Refer to Operation and Maintenance Manual, "High Pressure Fuel Lines".If the fuel system is Not OK, repair the fuel system and restart the diagnostic process.If the fuel system is OK, proceed to Test Step 4.
Not OK - There is an open circuit. Proceed to Test Step 4.Test Step 4. Check the Fuel Rail Pump Solenoid for an Open Circuit
Turn the keyswitch to the OFF position.
Disconnect the connector for the fuel rail pump solenoid from the fuel rail pump solenoid.
Measure the resistance of the fuel rail pump solenoid. Expected Result:The nominal resistance is less than 1.0 Ohms.Results:
OK - There is an open circuit or there is an excessive resistance in the harness.Repair: Repair the connectors or the harness and/or replace the connectors or the harness.Ensure that all of the seals are correctly in place and ensure that all connectors are correctly coupled.Use the electronic service tool in order to clear all logged diagnostic codes.Use the electronic service tool in order to perform the fuel rail pump solenoid test.Verify that the repair eliminated the fault.STOP
Not OK - The fuel rail pump solenoid is faulty.Repair: Temporarily connect a new fuel rail pump to the harness, but do not install the fuel rail pump to the engine.Reconnect the P2 to the ECM. Check the screw for the ECM connector for the correct torque of 5.0 N m (44 lb in).Use the electronic service tool in order to perform the fuel rail pump solenoid test.Verify that the repair eliminated the fault.If the diagnostic code has been cleared, install the new fuel rail pump to the engine. Refer to Disassembly and Assembly Manual, "Fuel Injection Pump - Install".STOPTest Step 5. Check the Fuel Rail Pump Solenoid for a Short Circuit
Turn the keyswitch to the OFF position.
Disconnect the connector for the fuel rail pump solenoid.
Turn the keyswitch to the ON position.
Use the electronic service tool in order to perform the test on the fuel rail pump solenoid. Expected Result:A Current Below Normal diagnostic code is displayed. The Current Above Normal diagnostic code is not displayed.Results:
OK - A Current Below Normal diagnostic code is displayed. The harness has no shorts to supply or ground. The fuel rail pump solenoid is faulty.Repair: Temporarily connect a new fuel rail pump to the harness, but do not install the fuel rail pump to the engine.Reconnect P2 to the ECM. Check the screw for the ECM connector for the correct torque of 5.0 N m (44 lb in).Use the electronic service tool in order to clear all logged diagnostic codes.Use the electronic service tool in order to perform the test on the fuel rail pump solenoid.Verify that the repair eliminates the fault.If the diagnostic code has been cleared, then install the new fuel rail pressure pump to the engine. Refer to Disassembly and Assembly, "Electrical Connectors - Inspect".STOP
Not OK - The harness is a short circuit or the ECM is a short circuit. Proceed to Test Step 6.Test Step 6. Check the Harness for the Fuel Rail Pump Solenoid for a Short Circuit
Turn the keyswitch to the OFF position.
Disconnect the P532 connector from the fuel rail pump solenoid.
Disconnect the P2 c