12675A18 Mercruiser HOUSING ASSEMBLY, Flywheel, Flywheel

Illustration 1 g01232509
Schematic of the circuit for the pressure sensor supply
Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the ECM.
Illustration 2 g01142382
Left side engine view
(1) Intake manifold pressure sensor
(2) Atmospheric pressure sensor
(3) Engine oil pressure sensor
(4) Fuel pressure sensor
(5) J2/P2 ECM conntector
(6) J1/P1 ECM conntector
Illustration 3 g01142856
Air filter assembly
(7) Turbocharger inlet pressure sensor
Thoroughly inspect connectors (5) and (6). Also, thoroughly inspect the connectors for sensors (1), (2), (3), (4), and (7). Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 4 g01204484
P2 ECM connector
(P2-15) Intake manifold pressure sensor
(P2-17) Sensor return
(P2-28) Engine oil pressure sensor
(P2-40) Fuel pressure sensor
(P2-57) Atmospheric pressure sensor
(P2-72) +5 V supply
Illustration 5 g01218807
P1 ECM connector
(P1-2) +5 V supply
(P1-3) Sensor return
(P1-15) Right turbocharger inlet pressure
Illustration 6 g01159881
Harness connector for the engine pressure sensors
(A) Sensor supply
(B) Sensor return
(C) Sensor signal
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors that are associated with the circuit.
Check the allen head screw for each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasion and for pinch points from the sensors back to the ECM. Expected Result:All 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 - There is a problem with the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. 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 the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Restore electrical power to the ECM.
Monitor the active diagnostic code screen on Cat ET. Check for an active 262-03 code and an active 262-04 code. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Remove electrical power from the ECM. Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active.Repair: If any of the above codes are logged and the engine is not running properly, refer to Troubleshooting, "Troubleshooting Without a Diagnostic Code".If the engine is running properly at this time, there may be an intermittent problem in a harness that is causing the codes to be logged. Refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - Either the 262-03 or 262-04 diagnostic code is active at this time. Proceed to Test Step 3.Test Step 3. Disconnect the Pressure Sensors and Check for Active Diagnostic Codes
Restore electrical power to the ECM.
Monitor the active diagnostic code screen on Cat ET while you disconnect each pressure sensor connector. Check for an active 262-03 code or an active 262-04 code. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Disconnect the following sensors one at a time:
Atmospheric pressure sensor
Intake manifold pressure sensor
Engine oil pressure sensor
Fuel pressure sensor
Turbocharger inlet pressure sensor
Remove electrical power from the ECM. Expected Result:The diagnostic code deactivates when a particular sensor is disconnected.Results:
OK - The 262-03 or 262-04 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 262-03 or 262-04 diagnostic code remains active after all of the sensors are disconnected. The sensors are not the cause of the diagnostic code. Leave the sensors disconnected. Proceed to Test Step 4.Test Step 4. Check the Supply Voltage at the ECM
Disconnect the J2/P2 ECM connectors.
Fabricate two jumper wires that are long enough to be used as test leads at the ECM connectors. Crimp connector sockets to one end of each jumper wire.
Remove the wires from terminal locations P2-72 (5 V sensor supply) and P2-17 (sensor return). Install a jumper wire into each of these terminal locations.
Connect the J2/P2 ECM connectors.
Restore electrical power to the ECM.
Measure th