9003A 2 Mercury COVER ASSEMBLY

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Schematic for the 5 V supplyTest Step 1. Inspect the Electrical Connectors and Wiring
Set the engine control to the OFF/RESET mode. Switch the 16 amp circuit breaker OFF.Note: For the following steps, refer to Troubleshooting, "Inspecting Electrical Connectors".
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Terminal box for the master ECM (1) J1/P1 connectors for the master ECM (2) J12/P12 connectors for the 5 volt sensors (3) 16 amp circuit breaker (4) J9/P9 connector for the "DESIRED SPEED" potentiometer (if equipped)
Thoroughly inspect each of the following connectors:
Master ECM J1/P1 connectors
J9/P9 and J12/P12 connectors on the terminal box
Check the torque of the Allen head screws for the ECM connectors. The proper torque is 6 1 N m (55 9 lb in).
Illustration 3 g00979496
Harness side of the master ECM P1 connector (P1-2) 5 volt supply (P1-3) Return (P1-11) Signal for the humidity (P1-14) Signal for the inlet manifold air temperature (P1-16) Signal for the desired speed (P1-17) Signal for the engine oil temperature (P1-18) 5 volt supply (P1-24) Signal for the filtered engine oil pressure (P1-26) Signal for the unfiltered engine oil pressure (P1-35) Return
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Harness side of the P9 connector (P9-H) 5 volt supply (P9-I) Signal for the desired speed (P9-J) Return for the signal for the desired speed
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Harness side of the P12 connector (P12-A) 5 volt supply (P12-C) Return (P12-E) Signal for the unfiltered engine oil pressure (P12-F) Signal for the filtered engine oil pressure (P12-G) Signal for the humidity (P12-H) Signal for the engine oil temperature (P12-K) Signal for the inlet air temperature
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the 5 V sensors.
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(5) Inlet air temperature sensor (6) Engine coolant temperature sensor
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(7) Unfiltered oil pressure sensor (8) Filtered oil pressure sensor (9) Oil temperature sensor
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(10) Humidity sensor
Check the harness and wiring for corrosion, abrasion and pinch points from each 5 volt sensor to the master ECM.Expected Result:All connectors, pins, and sockets are connected properly. The connectors and the wiring do not have corrosion, abrasion, or pinch points.Results:
OK - All connectors, pins, and sockets are connected properly. The connectors and the wiring do not have corrosion, abrasion, or pinch points. The components are in good condition with proper connections. Proceed to Test Step 2.
Not OK - At least one of the connectors, pins, or sockets are not connected properly. At least one of the connectors and the wiring has corrosion, abrasion, and/or pinch points.Repair: Perform the necessary repairs and/or replace parts, if necessary.STOPTest Step 2. Check for Diagnostic Codes
Connect Cat ET to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Rotate the "DESIRED SPEED" potentiometer (if equipped) counterclockwise to the minimum speed position.
Switch the 16 amp circuit breaker ON. Set the engine control to the STOP mode.
Observe the "Active Diagnostic" screen on Cat ET. Wait at least 30 seconds so that any codes may become activated. Look for these codes:
262-03 5 Volt Sensor DC Power Supply short to +batt
262-04 5 Volt Sensor DC Power Supply short to ground
Observe the "Logged Diagnostic" screen on Cat ET. Look for the same codes.Expected Result:The 262-03 code or the 262-04 code is not active or logged.Results:
No codes - There are no active codes or logged codes. If the engine is equipped with a "DESIRED SPEED" potentiometer, proceed to Test Step 3. Otherwise, the +5 V sensor voltage supply is operating correctly at this time. Resume normal operation. STOP.
Active cod