840359 Mercruiser DECAL, Mercury Racing

Illustration 1 g01250749
Location of the decelerator position sensor (typical location)
The decelerator position sensor provides a pulse width modulated signal that varies with the position of the decelerator. The Electronic Control Module (ECM) translates the signal into a percentage of the decelerator position sensor. The electronic service tool can be used in order to display this percentage as "Decelerator Position". The range for "Decelerator Position" is 0 to 100 percent.
Illustration 2 g01511973
Schematic for the decelerator position sensor
Illustration 3 g01513034
A typical view of the P1connector (harness side) pin locations.
(P1-34) Digital return
(P1-43) +8 Volt DC digital supply
(P1-53) Decelerator position
Illustration 4 g01159881
Terminal locations at the connector for the decelerator position sensor
(Terminal A) +8 Volt DC digital supply
(Terminal B) Digital return
(Terminal C) Decelerator position Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove the electrical power from the ECM.
Thoroughly inspect the J1/P1 ECM connectors, the machine connectors, and the connectors for the decelerator position sensor. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the sensor connectors that are associated with the active diagnostic code.
Check the allen head screw for each of the ECM connectors and the machine connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasions and for pinch points from the sensor 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.Results:
OK - The harness and connectors appear to be OK. Proceed to Test Step 2.
Not OK - There is a fault 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.If necessary, perform a "Wiggle Test" by using the electronic service tool in order to identify intermittent connections.Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the fault.STOPTest Step 2. Inspect the Decelerator Pedal Assembly
Inspect the decelerator pedal assembly for components that are loose, bent, missing, or worn.
Slowly depress the pedal and release the pedal. Expected Result:The decelerator pedal assembly operates smoothly without excessive drag. The pedal returns to the fully released position without assistance in less than one second.Results:
OK - The decelerator pedal assembly functions properly. Proceed to Test Step 3.
Not OK - There is a mechanical problem with the decelerator pedal assembly.Repair: Repair the decelerator pedal assembly, as required.Verify that the repair eliminates the fault.STOPTest Step 3. Check the Status for "Decelerator Position"
Connect the electronic service tool to the service tool connector.
Restore the electrical power to the ECM.
Observe the status for "Decelerator Position" on the electronic service tool while the decelerator pedal is operated.
Remove the electrical power from the ECM. Expected Result:The status is approximately 0 percent when the decelerator pedal is released. The status progressively increases to 100 percent when the decelerator pedal is fully depressed.Note: This range can change depending on the adjustment of the decelerator pedal assembly.Results:
OK - The decelerator position sensor is working correctly.Repair: There may be an intermittent electrical problem in the harness or in a connector. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - The status is not correct on the electronic service tool. There may be a fault with the decelerator position sensor. Proceed to Test Step 4.Test Step 4. Check the Supply Voltage at the Sensor
Disconnect the connectors for the decelerator position sensor.
Restore the electrical power to the ECM.
Measure the voltage between terminals A and B on the harness side of the sensor connector.
Remove the electrical power from the ECM. Expected Result:The voltage is 8.0 0.5 Volts DC.Results:
OK - The voltage is 8.0 0.5 Volts DC. The voltage is correct. Proceed to Test Step 5.
Not OK - The voltage is not 8.0 0.5 Volts DC.Repair: The supply voltage is not reaching the sensor. Refer to Troubleshooting, "Digital Sensor Supply Circuit - Test".STOPTest Step 5. Check the Signal Frequency and the Duty Cycle at the Sensor
Remove the wire from terminal C (signal) on the harness side of the connector for the decelerator position sensor.
Install a 7X-6370 Adapter Cable As (3-PIN BREAKOUT) at the connector. Connect the connectors for the sensor.
Restore the electrical power to the ECM.
Use a multimeter to measure the signal frequency and the duty cycle between terminal B (digital return) and terminal C (signal) at the breakout while you operate the decelerator pedal.
Remove the electrical power from the ECM.
Remove the breakout from the circuit. Restore the wiring to the original configuration. Expected Result:The frequency is between 150 and 1000 Hz. The duty cycle is approximately 57 percent when the pedal is released. The duty cycle is approximately 32 percent when the pedal is fully depressed.Results:
OK - The signal frequency and the duty cycle are correct. The sensor is producing a valid signal. Proceed to Test Step 6.
Not OK - The signal frequency and/or the duty cycle are not correct.Repair: The sensor is not producing a valid signal. Replace the decelerator position sensor.Use the electronic service tool in order to clear any logged diagnostic codes and then verify that the repair eliminates the fault.STOPTest Step 6. Check the Signal Frequency and the Duty Cycle at the ECM
Disconnect the J1/P1 ECM connector.
Remove the wire from terminal P1-53 of the J1/P1 ECM connector.
Connect the J1/P1 ECM connector.
Restore the electrical power to the ECM.
Measure the frequency and the duty cycle between the disconnected wire from terminal P1-53 (decelerator position) and terminal P1-34 (digital return) while you operate the decelerator.
Remove the electrical power from the ECM. Expected Result:The frequency is between 150 and 1000 Hz. The duty cycle is approximately 57 percent when the pedal is released. The duty cycle is approximately 32 percent when the pedal is fully depressed.Results:
OK - The signal frequency and the duty cycle are correct. A valid sensor