888744 Mercruiser PULLEY, Timing Belt

Illustration 1 g00993477
Schematic of the 4 to 20 mA desired speed inputTest Step 1. Inspect the Electrical Connectors and Wiring
Set the engine control to the OFF/RESET mode. Switch the 16 amp circuit breaker OFF.Note: For the following steps, refer to Troubleshooting, "Inspecting Electrical Connectors".
Illustration 2 g00985627
Terminal box for the master ECM (1) 16 amp circuit breaker (2) J1/P1 connectors for the master ECM (3) J9/P9 connectors
Thoroughly inspect the following components:
ECM J1/P1 connectors
J9/P9 connectors on the terminal box
Wiring and the connections between the terminal box and the device that supplies the 4 to 20 mA signal
Check the torque of the Allen head screw for the master ECM connectors. The proper torque is 6 1 N m (55 9 lb in).
Illustration 3 g00905060
Harness side of the master ECM P1 connector (P1-36) + Signal (P1-37) - Signal
Illustration 4 g00890197
Harness side of the P9 connector (P9-K) + Signal (P9-P) - Signal
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the 4 to 20 mA circuit.
Check the harness and wiring for abrasion and pinch points between the device that supplies the 4 to 20 mA signal and the master ECM.Expected Result:All connectors, pins, and sockets are connected properly. The connectors and the wiring do not have corrosion, abrasion, or pinch points.Results:
OK - The components are in good condition with proper connections. If you are troubleshooting a "524-03 Desired Engine Speed Sensor short to +batt" diagnostic code, proceed to Test Step 2. If you are troubleshooting a "524-04 Desired Engine Speed Sensor short to ground" diagnostic code, proceed to Test Step 5.
Not OK - The components are not in good condition and/or at least one connection is improper.Repair: Perform the necessary repairs and/or replace parts, if necessary.STOPTest Step 2. Check for an Open Circuit
Remove the two wires ("+" and "-") for the 4 to 20 mA signal from the device that supplies the 4 to 20 mA signal.
Install a jumper wire between the two wires ("+" and "-") that were removed from the device that supplies the 4 to 20 mA signal.
Disconnect the P1 connector from the master ECM.
Illustration 5 g00905071
ECM side of the P1 connector (P1-36) + Signal (P1-37) - Signal
Use an ohmmeter to measure the resistance between terminals P1-36 and P1-37 on the ECM side of the P1 connector.Expected Result:The resistance is less than 5 ohms.Results:
OK - The resistance is less than 5 ohms. The circuit is not open.Repair: Remove the jumper wire. Insulate the wire leads with electrical tape in order to ensure that the leads do not create a short circuit. Proceed to Test Step 3.
Not OK - The resistance is greater than 5 ohms. There is a problem with a connector and/or the wiring from the P1 connector.Repair: The problem may be between the P1 connector and the J9 connector. Alternatively, the problem may be between the P9 connector and the device that provides the 4 to 20 mA signal.Repair the connection and/or the wire, when possible. Replace parts, if necessary. Verify that the problem is resolved.STOPTest Step 3. Check for a Short Circuit to the +Battery at Terminal P1-36
Verify that the engine control is in the OFF/RESET mode and that the 16 amp circuit breaker is OFF.
Make sure that there is no electrical power to the device that provides the 4 to 20 mA signal.
Illustration 6 g00902098
ECM side of the P1 connector (P1-36) + Signal (P1-57) +Battery
Use an ohmmeter to measure the resistance between terminals P1-36 and P1-57.Expected Result:The resistance is greater than 20,000 ohms.Results:
Yes - The resistance is greater than 20,000 ohms. The wiring from terminal P1-36 is not shorted to the +battery side. Do not reconnect any connectors. Proceed to Test Step 4.
No - The resistance is less than 20,000 ohms. There is a problem with a connection and/or the wiring from terminal P1-36.Repair: The problem may be between the P1 connector and the J9 connector. Alternatively, the problem may be between the P9 connector and the device that provides the 4 to 20 mA signal.