72521 Mercruiser LOCKWASHER, Internal Tooth

Table 1
Diagnostic Codes for the Motorized Valves
J1939 Code CDL Code Code Description
(code descriptions may vary) Comments
649-5 3512-5 Engine Exhaust Back Pressure Regulator Control Command : Current Below Normal The ECM detects the following conditions:
A low current condition in the output for the exhaust back pressure regulator for 2 seconds
168 diagnostic codes are not active.
The ECM has been powered for at least 2 seconds.
If equipped, the warning lamp will come on. The ECM will log the diagnostic code.
649-6 3512-6 Engine Exhaust Back Pressure Regulator Control Command : Current Above Normal The ECM detects the following conditions:
A high current condition in the output for the exhaust back pressure regulator for 2 seconds
The ECM has been powered for at least 2 seconds.
If equipped, the warning lamp will come on. The ECM will log the diagnostic code.
649-7 E1263 (2) Engine Exhaust Back Pressure Regulator Control Command : Not Responding to Command The ECM detects the following conditions:
The signal from the exhaust back pressure regulator position sensor indicates that the valve is not in the desired position.
This diagnostic code can be caused by a loss of the 5 VDC supply to the exhaust back pressure regulator position sensor.
The ECM has been powered for at least 2 seconds.
If equipped, the warning lamp will come on. The ECM will log the diagnostic code.
2791 -5 3405-5 Engine Exhaust Gas Recirculation (EGR) Valve Control : Current Below Normal The ECM detects the following conditions:
A low current condition in the output for the NOx Reduction System (NRS) valve (EGR valve) for 2 seconds
168 diagnostic codes are not active.
The ECM has been powered for at least 2 seconds.
If equipped, the warning lamp will come on. The ECM will log the diagnostic code.
2791-6 3405-6 EGR Valve Control : Current Above Normal The ECM detects the following conditions:
A high current condition in the output for the NRS valve (EGR valve) for 2 seconds
The ECM has been powered for at least 2 seconds.
If equipped, the warning lamp will come on. The ECM will log the diagnostic code.
2791-7 E1121 (2) EGR Valve Control Not Responding to Command The ECM detects the following conditions:
The signal from the NRS valve position sensor indicates that the valve is not in the desired position.
This diagnostic code can be caused by a loss of the 5 VDC supply to the NRS valve position sensor.
The ECM has been powered for at least 2 seconds.
If equipped, the warning lamp will come on. The ECM will log the diagnostic code. The following background information is related to this procedure:NRS valve (EGR valve)The NRS valve (EGR 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.Exhaust Back Pressure RegulatorThe Exhaust Back Pressure Regulator (EBPR) is used to promote regeneration of the Diesel Particulate Filter (DPF). When the soot level in the DPF is high, the ECM commands the EBPR to close. As the EBPR closes, the increased back pressure causes the engine to increase fuel flow. The increased fuel flow raises the exhaust gas temperature and therefore accelerates the regeneration process in the DPF.As the soot level in the DPF reduces, the ECM commands the EBPR to open, reducing the exhaust back pressure to a normal level.The EBPR is also used on engines with no DPF to assist deposit management.The position of the EBPR is calculated by the software that is contained in the ECM. The EBPR is controlled by a PWM signal from the ECM.Air System Motor Valves Verification TestThe Air System Motor Valve Verification Test will identify whether the EGR valve, and the EBPR are working correctly. This test must be run when the engine speed is zero and the battery voltage is within an acceptable range. For a 12VDC system, the service test must only be executed if the battery voltage is between 9VDC and 16VDC. For a 24VDC system, the battery voltage must be between 18VDC and 32VDC. If the battery voltage is outside of these ranges at any time, the test must be aborted. The test will also be aborted if a position sensor diagnostic, a motor short diagnostic, or a motor open circuit diagnostic become active.If at any point during the test the engine speed is not zero, the test will abort. The test moves the valves to various positions and then 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 EGR valve. If a test threshold is exceeded or any related diagnostics become active, the test will abort and generate an error identifier.During the following procedure, refer to the electrical schematic for the application.Complete the procedure in the order in which the steps are listed.
Illustration 1 g06194085
Table 2
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Turn the keyswitch to the OFF position.
B. Thoroughly inspect the connectors for the motorized valves. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the motorized valves.
D. Check the screw for the ECM connector for the correct torque of 6 N m (53 lb in).
E. Check the harness and wiring for abrasion and for pinch points from the motorized valves to the ECM.
Loose connection or damaged wire
Result: There is a fault in a connector or the wiring.
Repair: Repair any faulty connectors or replace the wiring harness. Ensure that all the seals are properly in place and ensure that the connectors are correctly coupled.
Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
Result: All connectors, pins, and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion, and pinch points.
Proceed to Test Step 2.
2. Check for Diagnostic Codes
A. Turn the keyswitch to the OFF position.
B.