879172110 Mercruiser PLUG

Illustration 1 g00770279
SchematicTest Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect the J1/P1 ECM connector, the J3/P3 machine connector, and the J35/P35 throttle position sensor connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.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.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 2. Inspect the Throttle Pedal Assembly
Inspect the throttle pedal assembly for components that are loose, bent, missing, or worn.
Slowly depress the pedal and release the pedal.Expected Result:The throttle pedal assembly operates smoothly without excessive drag. The pedal returns to the low idle position without assistance in less than one second.Results:
OK - The throttle pedal assembly functions properly. Proceed to Test Step 3.
Not OK - Repair: Repair the throttle pedal assembly, as required.STOPTest Step 3. Check the Status of the Throttle Position
Connect the Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position.
Observe the status for "Throttle Position" on Cat ET while you operate the throttle pedal.Expected Result:The status is approximately 0 percent when the throttle pedal is released. The status progressively increases to 100 percent when the throttle pedal is fully depressed.Note: This range can change depending on the adjustment of the throttle pedal assembly.Results:
OK - The throttle position sensor is working properly.Repair: Refer to Troubleshooting, "Electrical Connectors - Inspect" if the problem is intermittent.STOP
Not OK - Proceed to Test Step 4.Test Step 4. Check the Supply Voltage at the Sensor
Install a 7X-6370 Adapter Cable (three-pin breakout) at the J35/P35 throttle position sensor connector.
Turn the keyswitch to the ON position.
Measure the voltage across terminal A (+8 VDC) and terminal B (Return) at the J35/P35 breakout.Expected Result:The supply voltage is 8.0 0.5 VDC.Results:
OK - The sensor is receiving the correct supply voltage. Proceed to Test Step 5.
Not OK - Proceed to Test Step 10.Test Step 5. Check the Isolated Signal Frequency and the Duty Cycle at the Sensor
Remove the wire from the harness side of P35:C (Signal).
Turn the keyswitch to the ON position.
Measure the frequency and the duty cycle between terminal B (Return) and terminal C (Signal) at the J35/P35 breakout while you operate the throttle pedal.
Turn the keyswitch to the OFF/RESET position.
Reinstall the wire in P35:C (Signal).Expected Result:The frequency is between 150 and 1000 Hz. The duty cycle is between 10 and 22 percent when the pedal is released. The duty cycle is between 75 and 90 percent when the pedal is fully depressed.Results:
OK - The sensor is producing a valid signal. Proceed to Test Step 6.
Not OK - The sensor is not producing a valid signal.Repair: Replace the throttle position sensor.Verify that the repair eliminates the problem.STOPTest Step 6. Check for a Short Circuit in the Wiring Harness
Disconnect the J1/P1 ECM connector, the J2/P2 ECM connector, and the J35/P35 throttle position sensor connector.
Measure the following resistances:
P35:A (+8 VDC) to P35:B (Return)
P35:A (+8 VDC) to P35:C (Signal)
P35:B (Return) to P35:C (Signal)Expected Result:The resistance is greater than 20,000 Ohms for each measurement.Results:
OK - There are no shorts in the harness. Proceed to Test Step 7.
Not OK - There is a short circuit in the harness or connectors.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 7. Check the Resistance through the Harness
Illustration 2 g00938637
P1 ECM connector
Illustration 3 g00770282
P2 ECM connector
Fabricate a jumper wire with pins at both ends.
Use the jumper wire to short P35:A (Digital Sensor +8 VDC) and P35:C (Throttle Position) together.
Measure the resistance between P2:24 (Throttle Position) and P1:35 (Digital Sensor +8 VDC).
Move the one end of the jumper wire from P35:A (+8 VDC) to P35:B (Return). Leave the other end in P35:C (Signal).
Measure the resistance between P2:24 (Throttle Position) and P1:29 (Digital Return).
Remove the jumper wire and reconnect all of the connectors.Expected Result:The resistance is less than 10 Ohms for each measurement.Results:
OK - The harness is good. Proceed to Test Step 8.
Not OK - There is an open circuit or excessive resistance in the harness or the connectors.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 8. Check the Signal Frequency and the Duty Cycle at the ECM
Illustration 4 g00938637
J1/P1 breakout
Illustration 5 g00770282
J2/P2 breakout
Install a 7X-1715 Adapter Cable (Forty-Pin Breakout) and a 134-5195 Adapter Cable at the J1/P1 ECM connector.
Install a 7X-1715 Adapter Cable (Forty-Pin Breakout) and a 134-5195 Adapter Cable at the J2/P2 ECM connector.