806490T Mercruiser SENDER, Water Temperature (Single Station)

Illustration 1 g00940458Test Step 1. Check for Connector Damage.
Verify that the circuit breakers are not tripped.
Turn the battery disconnect switch to the OFF position.
Turn the keyswitch to the OFF position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the ECM connector (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
Check the customer connector (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
Check the harness and the wiring for abrasion and for pinch points. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring should be free of corrosion, abrasion or pinch points.Results:
OK - The connectors and wiring are okay. Proceed to Test Step 2.
Not OK - The connectors and/or wiring are not okay.Repair: Repair the connectors or wiring and/or replace the connectors or wiring.STOPTest Step 2. Check the Battery Voltage.
Turn the battery disconnect switch to the OFF position.
Turn the keyswitch to the OFF position.
Measure no-load battery voltage at the battery terminals. Refer to the Testing and Adjusting service manual for the proper procedures to check the batteries.
Load test the batteries. Use the 4C-4911 Battery Load Tester. Refer to the Operating Manual, SEHS9249. Refer to Special Instruction, SEHS7633. Expected Result:The no-load voltage at the batteries should be at least 23.5 VDC and the batteries should pass the load test.Results:
OK - The battery voltage is okay and the battery passes the load test. Proceed to Test Step 3.
Not OK - The battery voltage is incorrect and/or the battery fails the load test.Repair: The batteries or the alternator are causing the problem. Recharge the batteries or replace the batteries. Refer to the Testing and Adjusting service manual for the proper procedure for changing the battery and/or the alternator. Verify that the original condition is resolved.STOPTest Step 3. Check the Voltage Supply to the ECM.
Disconnect ECM connector J1/P1.
Turn the battery disconnect switch to the ON position.
Turn the keyswitch to the ON position.
Measure the voltage at the front engine ECM. Measure the voltage between P1-4 and P1-11 at ECM connector P1. Measure the voltage between P1-6 and P1-5 at ECM connector P1.
Measure the voltage at the rear engine ECM. Measure the voltage between P1-4 and P1-11 at ECM connector P1. Measure the voltage between P1-6 and P1-5 at ECM connector P1.
Measure the voltage at the master ECM. Measure the voltage between P1-4 and P1-5 at ECM connector P1.
Turn the keyswitch to the OFF position. Expected Result:The voltage should be 24 3 VDC.Results:
OK - The voltage is 24 3 VDC. Proceed to Test Step 4.
Not OK - The voltage is not 24 3 VDC. There is an open circuit or excessive resistance in the wiring.Repair: Verify that the breaker for the ECM is not tripped. Check for system voltage at the breaker for the ECM. If voltage is present at the breaker for the ECM, repair the wiring and/or connectors between the breaker and the ECM. If voltage is not present at the breaker for the ECM, the wiring and/or connectors between the battery and the breaker for the ECM are damaged. Verify that wire 229-BK(Black) from ECM connector P1-5 and P1-11 is not open. If necessary, repair the wiring and/or connectors. Refer to Illustration 1.STOPTest Step 4. Check the Voltage at the Input for the Keyswitch to the ECM.
Turn the keyswitch to the ON position.
Measure the voltage between P1-23 and P1-11 at the front engine ECM.
Measure the voltage between P1-23 and P1-11 at the rear engine ECM.
Measure the voltage between P1-06 and P1-05 at the master ECM.
Turn the keyswitch to the OFF position. Expected Result:The voltage should be 24 3 VDC.Results:
OK - The voltage is 24 3 VDC. Proceed to Test Step 5.
Not OK - The voltage is not 24 3 VDC. Proceed to Test Step 6.Test Step 5. Check the Voltage at the Digital Sensor Supply and the Analog Sensor Supply.Note: The circuit for the front engine begins with the letter T. The circuit for the rear engine begins with the letter R.
Turn the keyswitch to the OFF position. The engine should be OFF.
Check the voltage at the digital sensor supply.
If you are troubleshooting the digital supply for the front engine ECM or for the rear engine ECM, remove the wire P1-35 (800-OR(Orange)) from the harness side of ECM connector P1. Install a wire jumper with a socket on one end into P1-35. Remove the wire P2-35 (X800-OR(Orange)) from the harness side of ECM connector P2 if you are troubleshooting the digital supply for the master ECM. Install a wire jumper with a socket on one end into P2-35.
Remove the wire P1-29 (998-BR(Brown)) from the harness side of ECM connector P1. Install a wire jumper with a socket on one end into P1-29. Note: If you remove the sensor common from the ECM, an open circuit diagnostic code will be generated for all sensors that use the sensor common. Troubleshoot the original code. Delete the logged diagnostic codes when you are finished.
If you are troubleshooting the digital supply for the front engine ECM or for the rear engine ECM, reconnect ECM connector J1/P1. Reconnect the Master ECM connector J1/P1 and J2/P2 if you are troubleshooting the digital supply for the master ECM.
Turn the keyswitch to the ON position. The engine should be off.
If you are troubleshooting the digital supply for the front engine ECM or the rear engine ECM, measure the voltage between the jumpers in the digital sensor supply P1-35 and the digital sensor return P1-29. Measure the voltage between the jumpers in the digital supply P2-35 and the digital return P1-29 if you are troubleshooting the digital supply for the master ECM.
Turn the keyswitch to the OFF position. The engine should be