C4.4 and C6.6 Engines Caterpillar

Motorized Valve - Test

Usage:

C4.4 448

This procedure covers the following codes:

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Table 1
Diagnostic Codes for the Motorized Valves
J1939 Code	CDL Code	Code Description (code descriptions may vary)	Comments
649-3	3512-3	Engine Exhaust Back Pressure Regulator Control Command : Voltage Above Normal	The ECM detects the following conditions: A high-voltage 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.
649-5	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 -3	3405-3	Engine Exhaust Gas Recirculation (EGR) Valve Control : Voltage Above Normal	The ECM detects the following conditions: A high-voltage 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 -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 Regulator

The 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 Test

The 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.

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Illustration 1	g06374253
Schematic for the motorized valves

Complete the procedure in the order in which the steps are listed.

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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 ON position. D. Measure the voltage at the harness connector for the valve from the 5 VDC supply terminal of the position sensor to the sensor ground terminal.	4.84 to 5.16 VDC	Result: The voltage from the terminal for the 5 VDC supply to the sensor common terminal measures 4.84 to 5.16 VDC. Repair: Reconnect the suspect valve. Operate the engine for enough time to allow the engine to reach normal operating temperature. The suspect valve may be not responding due to frozen condensation. Use the electronic service tool to run the "Air System Motor Valves Verification Test". If the fault is cleared, return the engine to service. If the -7, (E1263 (2) or E1121 (2)) code is still active, replace the suspect valve. Refer to Disassembly and Assembly for more information. Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair eliminates the fault. Result: The sensor supply voltage is out of the nominal range. A 5 VDC supply diagnostic code is active. The fault is in the 5 VDC supply wire or the ground wire in the engine harness. Repair: Repair the faulty wiring or replace the faulty harness. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.
4. Create a Short Circuit at the Valve Connector A. Turn the keyswitch to the OFF position. B. Disconnect the connector for the suspect valve. C. Fabricate a jumper wire that is 150 mm (6 inch) long. D. Install the jumper between the signal and return pins on the connector for the suspect valve to create a short circuit. E. Turn the keyswitch to the ON position. Check for active diagnostic codes on the electronic service tool. F. Remove the jumper wire from the connector for the motorized valve.	Open circuit	Result: A -6 diagnostic code is active when the jumper wire is installed. A -3 or -5 diagnostic code is active with the jumper removed. Repair: Reconnect the valve. Check for active diagnostic codes on the electronic service tool. Wait at least 30 seconds in order for the codes to be displayed. If the -3 or -5 diagnostic code returns, then replace the valve. Refer to Disassembly and Assembly for the correct procedure. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: A -3 or -5 diagnostic code is still active with the jumper installed. Proceed to Test Step 5.
5. Check the Wiring for an Open Circuit A. Turn the keyswitch to the OFF position. B. Disconnect the P2 connector and the connector for the suspect valve. C. For the EBPR, use a multimeter to check the resistance between terminal 4 on the valve connector and P2:48. D. For the EBPR, use a multimeter to check the resistance between terminal 6 on the valve connector and P2:58. E. For the NRS valve, use a multimeter to check the resistance between terminal 4 on the valve connector and P2:32. F. For the NRS valve, use a multimeter to check the resistance between terminal 6 on the valve connector and P2:40. G. Reconnect the connectors.	Less than 2 Ohms	Result: All measured resistances are less than 2 Ohms. Contact the Dealer Solutions Network (DSN). Result: One or more of the measured resistances is greater than 2 Ohms. There is a fault in the wiring. Repair: Repair the valve connector or replace the wiring harness. Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair eliminates the fault.
6. Create an Open Circuit at the Valve Connector A. Turn the keyswitch to the OFF position. B. Disconnect the connector for the suspect valve to create an open circuit. C. Turn the keyswitch to the ON position. Check for active diagnostic codes on the electronic service tool. Wait at least 30 seconds in order for the codes to be displayed.	Diagnostic codes	Result: A -3 or -5 diagnostic code is now active. There is a short in the valve. Repair: Reconnect the valve. Check for active diagnostic codes on the electronic service tool. Wait at least 30 seconds in order for the codes to be displayed. If the -3 or -5 diagnostic code returns, then replace the valve. Refer to Disassembly and Assembly for the correct procedure. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: There is still a -3 or -5 diagnostic code. Proceed to Test Step 7.
7. Check the Wiring for a Short Circuit A. Turn the keyswitch to the OFF position. B. Disconnect the P2 connector and the connector for the suspect valve. C. For the EBPR, use a multimeter to check the resistance between P2:48 and all other terminals on the P2 connector. D. For the EBPR, use a multimeter to check the resistance between P2:58 and all other terminals on the P2 connector. E. For the NRS valve, use a multimeter to check the resistance between P2:32 and all other terminals on the P2 connector. F. For the NRS valve, use a multimeter to check the resistance between P2:40 and all other terminals on the P2 connector. G. Reconnect the connectors.	Greater than 1 k Ohm	Result: All measured resistances are greater than 1 k Ohm. Contact the Dealer Solutions Network (DSN). Result: One or more of the measured resistances is less than 1 k Ohm. There is a fault in the wiring. Repair: Repair the valve connector or replace the wiring harness. Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair eliminates the fault. If the fault has not been eliminated, contact the Dealer Solutions Network (DSN).