863444T 1 Mercruiser HOUSING, Water Distribution

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Schematic
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P1 and P2 ECM connectors
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Sensor connectorTest Step 1. Check for Active +5 V Sensor Supply Diagnostic Codes
Connect the Caterpillar Electronic Technician (Cat ET) to the data link connector.
Turn the keyswitch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.
Verify if any of the following diagnostic codes are active:
262-03 5 Volt Sensor DC Power Supply short to +batt
262-04 5 Volt Sensor DC Power Supply short to groundExpected Result:None of the preceding diagnostic codes are active.Results:
OK - Proceed to Test Step 2.
Not OK - There are active diagnostic codes for the 5 Volt sensor supply.Repair: Perform the following diagnostic procedure: Troubleshooting, "Analog Sensor Supply Circuit - Test". Stop.Test Step 2. Inspect Electrical Connectors And Wiring
Thoroughly inspect the J2/P2 ECM connector, and the connectors for any suspect sensors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and in the sensor connectors that are associated with the active diagnostic code.
Check the ECM connector (Allen head screw) for the proper torque of 2.25 N m (20 lb in).
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 - Proceed to Test Step 3.
Not OK - 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.Clear all logged diagnostic codes. Stop.Test Step 3. Determine the Condition that is Present
Turn the keyswitch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.
Monitor the active diagnostic code screen on Cat ET.
Determine if the problem is related to an open circuit diagnostic code or a short circuit diagnostic code.Expected Result:Either an open circuit diagnostic code or a short circuit diagnostic code is active.Results:
Short Circuit - A short circuit diagnostic code is active at this time. Proceed to Test Step 4.
Open Circuit - An open circuit diagnostic code is active at this time. Proceed to Test Step 7.Test Step 4. Disconnect the Suspect Sensor
Turn the keyswitch to the OFF position.
Disconnect the sensor with the short circuit diagnostic code.
Turn the keyswitch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.
Check for an active open circuit diagnostic code for the disconnected sensor.Expected Result:An open circuit diagnostic code is now active for the disconnected sensor.Results:
OK - A short circuit diagnostic code was active before disconnecting the sensor. An open circuit diagnostic code became active after disconnecting the sensor.Repair: Temporarily connect a new sensor.Check for active diagnostic codes.If the new sensor fixes the problem, reconnect the suspect sensor.If the problem returns, permanently install the new sensor.Verify that the repair eliminates the problem. Stop.
Not OK - There is a short circuit between the sensor and the ECM.Repair: Leave the suspect sensor disconnected. Proceed to Test Step 5.Test Step 5. Create an Open Circuit at the ECM
Turn the keyswitch to the OFF position.
Remove the signal wire of the suspect sensor from the P2 ECM connector.
Turn the keyswitch to the ON position.
Check for active diagnostic codes.Expected Result:An open circuit diagnostic code became active after disconnecting the signal wire.Results:
OK - A short circuit diagnostic code was active before disconnecting the sensor. An open circuit diagnostic code became active after disconnecting the sensor. Proceed to Test Step 6.
Not OK - There is still a short circuit diagnostic code.Repair: Connect a test ECM.If the test ECM fixes the problem, reconnect the suspect ECM.If the problem returns, permanently replace the suspect ECM.Verify that the repair eliminates the problem. Stop.Test Step 6. Check the Resistance of the Harness
Turn the keyswitch to the OFF position.
Verify that the suspect sensor is disconnected.
Measure the resistance between terminal B (Sensor Return) and terminal C (Signal) of the connector for the suspect sensor on the engine harness.Expected Result:The resistance is greater than 20,000 Ohms, or "OL" is displayed on the multimeter.Results:
OK - The resistance is greater than 20,000 Ohms, or "OL" is displayed on the multimeter.Repair: Check the signal wire for a short to ground.Repair the faulty wiring or replace the faulty wiring.Verify that the repair eliminates the problem. Stop.
Not OK - There is a short between the analog sensor common and the signal wire.Repair: Locate the short between the analog sensor common and the signal wire.Repair the faulty wiring or replace the faulty wiring.Verify that the repair eliminates the problem. Stop.Test Step 7. Measure the Sensor Supply Voltage
Turn the keyswitch to the OFF position.
Disconnect the suspect sensor.
Turn the keyswitch to the ON position.
Measure the voltage from terminal A (Analog Sensor +5V) to terminal B (Sensor Return).Expected Result:The voltage is 5.0 0.2 VDC.Results:
OK - The sensor supply voltage is correct.Repair: Leave the sensor disconnected. Proceed to Test Step 8.
Not OK - The sensor supply voltage is out of the specified range.Repair: Check the 5 volt supply wire for an open circuit.Repair the faulty wiring or replace the faulty wiring.Verify that the repair eliminates the problem. Stop.Test Step 8. Create a Short Circuit at the Sensor
Turn the keyswitch to the ON position.
Monitor the active diagnostic code screen on Cat ET.
Install a jumper wire between terminal C (Signal) and terminal B (Sensor Return) of the connector for the suspect sensor on the engine harness. Wait at least 15 seconds for activation of the short circuit diagnostic code.Expected Result:A short circuit diagnostic code is active when the jumper wire is installed. An open circuit diagnostic code is active when the jumper wire is removed.Results:
OK - The engine harness and the ECM are OK.Repair: Temporarily co