803608 Mercruiser ELBOW-EXHAUST

Illustration 1 g01261839
Schematic
Illustration 2 g01260002
P1 ECM connector
(P1-4) +8 V digital supply
(P1-5) Digital return
(P1-45) Coolant level
(P1-66) Throttle position
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Terminal locations at the sensor connector
(Terminal A) +8 V digital supply
(Terminal B) Digital return
(Terminal C) Decelerator position Test Step 1. Inspect Electrical Connectors and Wiring
Remove the electrical power from the ECM.
Thoroughly inspect the J1/P1 ECM connector, the machine connector, the connector for the throttle position sensor and the connector for the coolant level sensor. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
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 ECM connector (allen head screw) for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
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 inserted and coupled. The harness and wiring are free of corrosion, of abrasion, and of pinch points. All connections and grounds are tight and free of corrosion.Results:
OK - The harness and connectors 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 for Active Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Restore the electrical power to the ECM.
Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.Expected Result:One of the following diagnostic codes is active:
41-03
41-04 Results:
OK - A 41-03 diagnostic code is active. Proceed to Test Step 3.
OK - A 41-04 diagnostic code is active. Proceed to Test Step 4.
Not OK - No diagnostic code for the digital supply is active. A problem is suspected with a sensor output signal. In order to verify that the sensor is receiving the correct supply voltage, proceed to Test Step 3.Test Step 3. Check the Voltage on the +8 V Supply Wire
Remove the electrical power from the ECM.
Disconnect all of the digital sensor at the sensor connectors.
Restore the electrical power to the ECM.
Measure the voltage between terminal A and terminal B at each sensor connector. Expected Result:The voltage is 8.0 0.5 VDC.Results:
OK - The voltage is 8.0 0.5 VDC. The voltage is correct.Repair: Reconnect the sensors. Clear all diagnostic codes. Check for active diagnostic codes. If the problem is intermittent, refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - The voltage is not 8.0 0.5 VDC. The voltage is incorrect. Proceed to Test Step 5.Test Step 4. Disconnect the +8 V Sensor while you Monitor the Active Diagnostic Codes
Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Disconnect the digital sensors one at a time at the sensor connector. Wait for 30 seconds after each sensor is disconnected. Check for an active diagnostic code on Cat ET. Expected Result:The 41-04 diagnostic code deactivates.Results:
OK - The 41-04 diagnostic code deactivates after a particular sensor is disconnected.Repair: Reconnect the sensor. If the problem returns after the reconnection of the sensor, disconnect the sensor. If the problem disappears after the disconnection of the sensor, replace the sensor. Clear all diagnostic codes. Verify that the repair eliminates the problem.STOP
Not OK - The 41-04 diagnostic code stays active. Leave the sensors disconnected. Proceed to Test Step 5.Test Step 5. Check the +8 V Supply Wire for a Short to Engine Ground or a Short to another Wire in the Harness
Remove the electrical power from the ECM.
Disconnect the J1/P1 ECM connector and the J2/P2 ECM connector.
Leave the digital sensors disconnected. Note: Wiggle the harness during the following measurements in order to reveal any intermittent short condition.
Measure the resistance between P1-4 (+8 V digital supply) and every terminal on ECM connector P1 and ECM connector P2.
Measure the resistance between P1-4 (+8 V digital supply) and engine ground. Expected Result:Each resistance measurement indicates an open circuit.Results:
OK - The resistance measurement does not indicate a short in the engine harness or a short to engine ground. Proceed to Test Step 6.
Not OK - A resistance measurement does not indicate an open circuit. The +8 V digital supply wire is shorted in the engine harness or the +8 V digital supply wire is shorted to engine ground.Repair: Repair the wire or replace the wire. Clear all logged diagnostic codes. Replace all wires to the original configuration. Verify that the repair eliminates the problem.STOPTest Step 6. Check the +8 V Supply and the Sensor Return for an Open Circuit
Install a wire jumper between pin P1-4 (+8 V digital supply) and pin P1-5 (digital return). Note: Wiggle the harness during the following measurements in order to reveal any intermittent short condition.
Measure the resistance between terminal A and terminal B at each of the sensor connectors.
Remove the wire jumper. Expected Result:The resistance is less than 10 Ohms for each measurement.Results:
OK - The resistance check does not indicate an open circuit in the engine harness. Proceed to Test Step 7.
Not OK - A resistance measurement is greater than 10 Ohms. The +8 V digital supply wire or the sensor common has excessive resistance.Repair: Repair the wires or replace the wires. Clear all logged diagnostic codes. Verify that the repair eliminates the problem.STOPTest Step 7. Check the +8 V Supply at the ECM
Remove the wire from ECM connector P1-4 (+8 V digital supply). Install a wire jumper with socket terminals on both ends into P1-4.
Remove the wire from ECM connector P1-5 (digital return). Install a wire jumper with socket terminals on both ends into P1-5.
Reconnect ECM connector J1/P1 and J2/P2.
Restore the electrical power to the ECM.
Measure the voltage