39131 Mercruiser LOCKWASHER, FLYWHEEL SCREW

The following background information is related to this procedure:NRS ValveThe NRS valve is used to control the amount of exhaust gas which is recirculated into the intake manifold.The amount of exhaust gas that is required is calculated by the software that is contained in the ECM. The NRS valve is controlled by a PWM signal from the ECM.Intake Throttle ValveThe intake throttle valve is used to increase the exhaust gas temperature to aid the regeneration process.Turbocharger EWGThe EWG is a valve that allows exhaust gas to bypass the turbine wheel of the turbocharger. The position of the valve varies the amount of exhaust gas that flows into the turbine."Air System Motor Valve Verification Test"The "Air System Motor Valve Verification Test" will identify whether the NRS valve, the intake throttle valve, and the turbocharger EWG are working correctly. This test must be performed when the engine speed is zero and the battery voltage is within an acceptable range. For a 12V system, the test must only be performed when the battery voltage is between 9V and 16V. For a 24V system, the test must only be performed when the battery voltage is between 18V and 32V. If the battery voltage is out of the required range, the test will be aborted.The "Air System Motor Valve Verification Test" will actively check position sensor diagnostics, motor short diagnostics, and motor open circuit diagnostics. The test will abort if any of these diagnostic codes become active.If the engine speed is not zero while the test is being performed, the test will be aborted. If no electrical diagnostic codes are active, the test will calibrate the NRS valve minimum position, the intake throttle valve minimum and maximum position, and the turbocharger EWG maximum position. The test then moves the valves to various positions and checks the position sensor within each valve to confirm that the valve has responded correctly. Each valve will be tested in turn, starting with the NRS valve. If a test threshold is exceeded or any related diagnostic codes become active, the test will abort and generate a service tool error identifier.
Illustration 1 g06356434
Schematic diagram for the motorized valves
Table 2
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Thoroughly inspect connectors for the motorized valves. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
B. Thoroughly inspect the engine interface connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Damaged wire or connector
Result: A damaged wire or damaged connector was found.
Repair: Repair the damaged wire or the damaged connector.
Use the electronic service tool to clear all logged diagnostic codes. Perform the "Air System Motor Valves Verification Test" and verify that the repair eliminates the fault.
Result: All connectors, pins, and sockets are correctly connected and/or inserted and the harness is free of corrosion, of abrasion or of pinch points.
Proceed to Test Step 2.
2. Check for Diagnostic Codes
A. Turn the keyswitch to the OFF position.
B. Connect the electronic service tool to the diagnostic connector.
C. Turn the keyswitch to the ON position.
D. Monitor the electronic service tool for active diagnostic codes and/or logged diagnostic codes.
Diagnostic codes
Result: A -7 diagnostic code is active or recently logged for one or more of the motorized valves
Proceed to Test Step 3.
Result: A -5 diagnostic code is active or recently logged for one or more of the motorized valves.
Proceed to Test Step 5.
Result: A -6 diagnostic code is active or recently logged for one or more of the motorized valves.
Proceed to Test Step 8.
3. Measure the Sensor Supply Voltage at the Valve Connector
A. Turn the keyswitch to the OFF position.
B. Disconnect the suspect valve from the engine harness.
C. Turn the keyswitch to the ON position.
D. Measure the voltage at the harness connector for the valve from the 5 V supply terminal of the position sensor to the sensor ground terminal.
4.84 V to 5.16 V
Result: The measured voltage is within the expected range.
Repair: Use the electronic service tool to perform the "Air System Motor Valves Verification Test". If the test passes, there may be an intermittent fault. Refer to Troubleshooting, Electrical Connectors - Inspect to identify intermittent faults.
If the test fails, install a replacement for the suspect valve. Refer to Disassembly and Assembly for more information.
If the turbocharger EWG is replaced, use the electronic service tool to perform the "Turbocharger Wastegate Actuator Replacement Reset".
If the NRS valve is replaced, use the electronic service tool to perform the "EGR Valve Replacement Reset".
If the intake throttle valve is replaced, use the electronic service tool to perform the "Engine Throttle Valve Replacement Reset".
Use the electronic service tool to clear all logged diagnostic codes. Perform the "Air System Motor Valves Verification Test" and verify that the repair eliminates the fault.
Result: The measured voltage is not within the expected range.
Reconnect the valve connector. Proceed to Test Step 4.
4. Measure the Sensor Supply Voltage at the Engine Interface Connector
A. Turn the keyswitch to the OFF position.
B. Disconnect the engine interface connector.
C. Turn the keyswitch to the ON position.
D. Measure the voltage at the engine interface connector on the harness between the engine and the ECM from the 5 VDC sensor supply terminal for the suspect valve to the sensor ground terminal .
4.84 V to 5.16 V
Result: The measured voltage is within the expected range.
The fault is in the 5 VDC supply wire or the ground wire between the suspect valve and the engine interface connector.
Repair: Repair the faulty wiring or replace the faulty wiring.
Use the electronic service tool to clear all logged diagnostic codes. Perform the "Air System Motor Valves Verification Test" and verify