827484M Mercury COVER

Illustration 1 g01212793
Schematic for the engine pressure sensors
Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the ECM.
Illustration 2 g01166192
Sensor locations (typical engine views)
(1) J2/P2 ECM conntector
(2) J1/P1 ECM conntector
(3) Fuel pressure sensor
(4) Engine oil pressure sensor
(5) Atmospheric pressure sensor
(6) Boost pressure sensor
(7) J61 customer connector
Thoroughly inspect connectors (1), (2), and (7). Also, thoroughly inspect the connectors for each pressure sensor. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 3 g01204484
P2 terminal locations
(P2-15) Boost pressure
(P2-17) Sensor return
(P2-28) Engine oil pressure
(P2-40) Fuel pressure
(P2-57) Atmospheric pressure
(P2-72) +5 V sensor supply
Illustration 4 g01212799
P1 ECM connector
(P1-2) +5 V sensor supply
(P1-3) Sensor return
(P1-15) Auxiliary pressure
Illustration 5 g01212800
Terminal locations at the P61 customer connector
(P61-14) +5 V sensor supply
(P61-15) Sensor return
(P61-33) Auxiliary pressure
Illustration 6 g01159881
Sensor connector
(Terminal A) +5 V sensor supply
(Terminal B) Sensor return
(Terminal C) Signal
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors and on each of the wires in the pressure sensor connectors.
Check the allen head screw for each ECM connector and the customer 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 pressure sensors back to the ECM. 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 appear to be 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. 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 the Supply Voltage at the Sensor Connector
Remove electrical power from the ECM.
Disconnect the harness connectors for the following sensors:
Atmospheric pressure sensor
Auxiliary pressure sensor
Boost pressure sensor
Engine oil pressure sensor
Fuel pressure sensor
Restore electrical power to the ECM. Note: The original diagnostic code may not stay active. An open circuit diagnostic code for the sensor supply may become active when all of the sensors are disconnected. Ignore the active codes at this time and continue with this test step.Note: Be sure to wiggle the harness during the following measurements in order to reveal an intermittent condition.
Measure the voltage between terminals A and B at each sensor connector on the engine harness.
Remove electrical power from the ECM.
Connect all of the sensors. Expected Result:Each voltage measurement is 5.0 0.2 VDC.Results:
OK - Each voltage measurement is 5.0 0.2 VDC. The voltage is correct at the sensor connectors. Proceed to Test Step 3.
Not OK - At least one voltage measurement is not 5.0 0.2 VDC.Repair: Refer to Troubleshooting, "5 Volt Engine Pressure Sensor Supply Circuit - Test".STOPTest Step 3. 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. Look for an active diagnostic code for an engine pressure sensor. Note: Wait at least 30 seconds so that any codes may become active.
Determine if the problem is related to an open circuit diagnostic code (03) or a short circuit diagnostic code (04). Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active for the engine pressure sensors.Repair: The original problem seems to be resolved. The problem may have been related to a faulty connection in the harness. Carefully reinspect the connectors and wiring. If an intermittent electrical problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - A 03 dia