19251-ZV1-701 Honda TUBE, WATER (L) (Honda Code 2650414).

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.EGR Valve Control Override TestThe EGR Valve Control Override Test will identify whether the NRS valve is working correctly. This test must be run when the engine speed is zero and the battery voltage is within an acceptable range. Only execute the service test if the battery voltage is between 9VDC and 16VDC. If the battery voltage is outside of this range 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 valve to various positions and then checks the position sensor within the valve to confirm that the valve has responded correctly. If a test threshold is exceeded or any related diagnostics become active, the test will abort and generate an error identifier.Intake Throttle ValveWhen necessary, the engine intake throttle valve reduces the intake manifold pressure so that the pressure in the NRS mixer is always higher. This pressure differential ensures that recirculated exhaust gases will flow into the intake manifold.The engine intake throttle valve is controlled by a PWM signal from the ECM.Intake Throttle Valve Override TestThe Intake Throttle Valve Override Test will identify whether the intake throttle valve is working correctly. This test must be run when the engine speed is zero and the battery voltage is within an acceptable range. Only execute the service test if the battery voltage is between 9VDC and 16VDC. If the battery voltage is outside of this range 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 valve to various positions and then checks the position sensor within the valve to confirm that the valve has responded correctly. If a test threshold is exceeded or any related diagnostics become active, the test will abort and generate an error identifier.
Illustration 1 g03832241
Schematic for the motorized valves
Illustration 2 g03833072
Connector on the NRS valve
(1) Motor -
(2) + 5 VDC
(3) Ground
(4) Position signal
(5) Motor +
Illustration 3 g03833076
Connector on the intake throttle valve
(1) Motor -
(2) Motor +
(3) Ground
(4) Not used
(5) + 5 VDC
(6) Position signal
Illustration 4 g03833114
Engine interface connector
(39) Intake throttle valve PWM return
(40) NRS valve PWM return
(41) Intake throttle valve PWM power
(42) NRS valve PWM powerComplete 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 wires in the ECM connector that are associated with the motorized valves.
D. 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 2791-X diagnostic code is active or recently logged.
Proceed to Test Step 3.
Result: A 2950-X diagnostic code is active or recently logged.
Proceed to Test Step 6.
Result: No diagnostic codes are active or logged.
Repair: For intermittent faults, refer to Troubleshooting, "Electrical Connectors - Inspect".
If no intermittent faults are found, proceed to Test Step 9.
3. Check the NRS Valve
A. Turn the keyswitch to the OFF position.
B. Disconnect the NRS valve from the engine harness.
C. Measure the resistance between pin 1 and pin 5 on the NRS valve. Refer to Illustration 2.
0.3 to 100 Ohms
Result: The resistance measurement is less than 0.3 Ohms or more than 100 Ohms.
Repair: Install a replacement N