74271 Mercruiser BELT, WATER PUMP

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 (EBPR) 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 EBPR 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 EBPR 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 EBPR 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.
1188–7 E2385 (1) Engine Turbocharger #1 Wastegate Drive : Not Responding Properly The Electronic Control Module (ECM) detects the signal from the turbocharger Electronic Wastegate (EWG) position sensor and indicates that the valve is not in the desired position.
This diagnostic code can be caused by an obstruction to the mechanical linkage to the wastegate within the turbine housing or due to a loss of the 5 VDC supply to the EWG position sensor.
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.
5421–5 526–5 Engine Turbocharger Wastegate Actuator #1 : Current Below Normal The ECM detects A low current condition in the output for the turbocharger EWG.
5421–6 526–6 Engine Turbocharger Wastegate Actuator #1 : Current Above Normal The ECM detects a high current condition in the output for the turbocharger EWG. 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 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.Turbocharger Electronic Wastegate (EWG)The 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 Valves Verification TestThe Air System Motor Valve Verification Test will identify whether the EGR valve, the EBPR, and Turbocharger Electronic Wastegate 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 will be aborted. The test will actively check position sensor diagnostics, motor short circuit diagnostics, and motor open circuit diagnostics. The test will abort if any of these diagnostics become active.If at any point during the test the engine speed is not zero, the test will abort. If no electrical diagnostic codes are active, the test will calibrate the EBPR, EWG, and the NRS valve maximum and minimum position in parallel. The test then 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 parallel. 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 g06460299
Schematic diagram for the motorized valves on a C7.1 and C4.4 TA engine
Illustration 2 g06416849
Schematic diagram for the motorized valves on a C4.4 TTA engine
Note: All connectors