77885 Mercury COVER, FUEL PUMP

Illustration 1 g01436855
Schematic for the 5 volt supply
Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove the electrical power from the ECM.
Illustration 2 g01199199
A typical left side view of the C9 engine
(1) Fuel pressure sensor
(2) Injection actuation pressure sensor
(3) Boost pressure sensor for the intake manifold
(4) Atmospheric pressure sensor
(5) Engine oil pressure sensor
(6) J2/P2 connectors
(7) ECM
(8) J1/P1 connectors
Illustration 3 g01255900
A typical left side view of the C7 engine
(9) Fuel pressure sensor
(10) Injection actuation pressure sensor
(11) Atmospheric pressure sensor
(12) Boost pressure sensor for the intake manifold
(13) Engine oil pressure sensor
(14) J2/P2 connectors
(15) ECM
(16) J1/P1 connectors
Thoroughly inspect the ECM connectors. Thoroughly inspect the connectors for each pressure sensor. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
Illustration 4 g01223554
P2 terminals that are associated with the 5 volt supply for the pressure sensors
(P2-17) Return
(P2-54) Return
(P2-72) +5 VDC
(P2-80) +5 VDC
Illustration 5 g01123211
Connectors for the sensors
(A) Supply
(B) Return
(C) Signal
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the pressure sensor supply.
Check the torque of the allen head screws for the ECM connectors. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
Check the harness and the wiring for abrasion and for pinch points from each sensor back to the ECM. Expected Result:All of the connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.Results:
OK - The harness and connectors appear to be OK. Proceed to Test Step 2.
Not OK - The connectors and/or wiring are not OK.Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.STOPTest Step 2. Check for Active Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Restore electrical power to the ECM.
Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes. Look for the following diagnostic codes:
03
04
10Note: Wait at least 30 seconds in order for the diagnostic codes to become active.Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic code is active.Repair: The problem is no longer present. If the problem is intermittent, refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - One of the diagnostic codes that is listed above is active at this time. Proceed to Test Step 3.Test Step 3. Disconnect the 5 Volt Sensors while you Monitor the Active Diagnostic Codes
Monitor the active diagnostic code screen on Cat ET while you disconnect each 5 Volt sensor at the sensor connector. Check for an active 03 code, an active 04 code, or an active 10 code. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Disconnect the following sensors one at a time:
Injection actuation pressure sensor
Boost pressure sensor for the intake manifold
Engine oil pressure sensor
Fuel pressure sensor
Atmospheric pressure sensor
Remove electrical power from the ECM. Expected Result:The diagnostic code deactivates when a particular sensor is disconnected.Results:
OK - The diagnostic code deactivates when a particular sensor is disconnected.Repair: Connect the suspect sensor. If the code returns, replace the sensor. Connect all of the connectors. Verify that the problem is resolved.STOP
Not OK - The diagnostic code remains active after all of the sensors are disconnected. Leave the sensors disconnected. The sensors are not the cause of the diagnostic code. Proceed to Test Step 4.Test Step 4. Check the 5 Volt Supply Voltages at the ECM
Disconnect the J2/P2 ECM connector.
Fabricate four jumper wires that are long enough to be used to measure the supply voltage at the ECM connectors. Crimp connector sockets to one end of each jumper wire.
Remove the wires from the following terminal locations and install a jumper wire into each of these terminal locations:
P2-72 (5 V sensor supply)
P2-17 (sensor return)
P2-80 (5 V sensor supply)
P2-54 (sensor return)
Connect the J2/P2 ECM connector.
Restore electrical power to the engine ECM.
Measure the voltage between the jumper wire in P2-72 (5 V sensor supply) and the jumper wire in P2-17 (sensor return).
Measure the voltage between the jumper wire in P2-80 (5 V sensor supply) and the jumper wire in P2-54 (sensor return).
Remove electrical power from the ECM. Expected Result:The voltage measurement is 5.0 0.2 VDC.Results:
OK - The voltage measurement is 5.0 0.2 VDC. The ECM is operating correctly.Repair: The supply wire is shorted to another wire in the harness or the supply wire is shorted to engine ground. Repair the supply wire.STOP
Not OK - The voltage measurement is not 5.0 0.2 VDC.Repair: Replace the ECM. Refer to electronic troubleshooting Troubleshooting, "Replacing the ECM".STOP