0389941 JOHNSON CARBURETOR ASSY.,Complete

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.
Illustration 1 g06374253
Schematic for the motorized valves
Complete the procedure in the order in which the steps are listed.
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 motorized valve wires in the ECM connector.
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. 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 -3 or -5 diagnostic code is active or recently logged for one or more of the motorized valves.
Proceed to Test Step 4.
Result: A -6 diagnostic code is active or recently logged for one or more of the motorized valves.
Proceed to Test Step 6.
Result: A -7, (E1263 (2) or E1121 (2)) diagnostic code is active or recently logged for one or more of the motorized valves.
Proceed to Test Step 3.
Result: No diagnostic codes are active or logged.
Repair: For intermittent faults, refer to Troubleshooting, "Electrical Connectors - Inspect".
If no intermittent faults are found, return the unit to service.
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