C4.4 and C6.6 Engines Caterpillar

NRS Mass Flow Rate Problem

Usage:

C4.4 448

This procedure covers the following diagnostic trouble code:

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Table 1
Diagnostic Trouble Code for NRS Mass Flow Rate Problem
J1939 Code	CDL Code	Code Description	Comments
2659-7	E1319 (2)	Engine Exhaust Gas Recirculation (EGR) Mass Flow Rate : Not Responding Properly	Actual mass flow through the NOx Reduction System (NRS) does not match the desired mass flow. The Electronic Control Module (ECM) has been powered for at least 2 seconds. The engine is running. There are no active codes for the 5 VDC supply. There are no active 27, 157, 411, 1188, 2791, 3358 or 3563 codes. 412-3 or 412-4 codes are not active.

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Illustration 1	g06101475
NRS system for a C4.4 engine (1) NRS inlet temperature sensor (2) NRS mixer (3) Pipe for the NRS differential pressure sensor (4) Pipe for the NRS inlet pressure sensor (5) Manifold for the NRS pressure sensors (6) NRS differential pressure sensor (7) NRS inlet pressure sensor

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Illustration 2	g06101479
NRS system for a C6.6 engine (1) NRS inlet pressure sensor (2) NRS outlet pressure sensor (3) Pipe for the NRS outlet pressure sensor (4) Pipe for the NRS inlet pressure sensor (5) NRS mixer (6) NRS inlet temperature sensor

Probable Causes

Diagnostic codes
Electrical connectors and harness
Air inlet and exhaust system
NRS inlet pressure sensor and sensor pipes
NRS temperature sensor
NRS mixer

Recommended Actions

Note: The procedures have been listed in order of probability. Complete the procedures in order.

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Table 2
Troubleshooting Test Steps	Values	Results
1. Diagnostic Codes A. Download the Warranty Report and the Product Status Report with Histograms before performing any troubleshooting or clearing any diagnostic codes. Note: The downloaded information will be required by the Technical Communicator if troubleshooting assistance is needed. B. Use the electronic service tool to check for active or logged codes.	Diagnostic codes	Result: A diagnostic code for the NRS valve is active or logged. Repair: Rectify the NRS valve code. Refer to Troubleshooting, "Motorized Valve - Test". Result: A 2659-7 code is active. Proceed to Test Step 2.
2. Inspect the Electrical Connectors and the Harness A. Turn the keyswitch to the OFF position. B. Inspect the connectors for the components in the NRS system. Refer to Troubleshooting, "Electrical Connectors - Inspect". C. Perform a 45 N (10 lb) pull test on each of the wires in any suspect connector and the connections at the ECM. D. Check that the ground connection on the ECM and the negative terminal on the battery are correctly installed. E. Check the ground connection on the ECM for abrasions and pinch points. F. Check the screws for the ECM connector for the correct torque of 6 N·m (53 lb in). G. Check the harness for abrasion and pinch points from the NRS components to the ECM. H. Check that any suspect connector is installed correctly.	Connectors and harness	Result: An electrical connector or a cable is not correctly installed. Repair: Install the connector or cable correctly. Result: The harness is faulty. Install a replacement harness. Result: The harness and connectors are OK. Proceed to Test Step 3.
3. Check the Air Inlet and Exhaust System A. Check the air inlet system for leaks and for restrictions. B. Check the exhaust system for leaks and for restrictions. C. Test the exhaust back pressure regulator. Refer to Troubleshooting, "Motorized Valve - Test".	Air inlet and exhaust system	Result: The air inlet system has a leak or is restricted. Repair: Clear any restrictions in the air inlet system. Repair any air leaks in the air inlet system. Result: The exhaust system has a leak or is restricted. Repair: Clear any restrictions in the exhaust system. Repair any air leaks in the exhaust system. If the fault is still present, proceed to Test Step 4.
4. Check the NRS Inlet Pressure Sensor and Sensor Pipes For a C4.4 engine, refer to Illustration 1. For a C6.6 engine, refer to Illustration 2. A. Check pipe (4) for the NRS inlet pressure sensor for leaks, restrictions, or blockage. B. Check pipe (3) for the NRS differential pressure sensor for leaks or any restriction. C. Test the exhaust back pressure regulator. Refer to Troubleshooting, "Motorized Valve - Test".	Pressure sensor and pipes	Result: There is a leak, a restriction, or a blockage in one of the sensor pipes. Repair: If a pipe has a leak or a restriction, replace the pipe. If a pipe is blocked with soot or condensates, remove the pipe. Use an air line that is set at a maximum pressure of 200 kPa (29 psi) to clear the blockage. If the blockage is cleared, install the pipe. If the blockage cannot be cleared, replace the pipe. Result: The NRS inlet pressure sensor is blocked. Repair: Replace the NRS inlet pressure sensor. Result: There are no leaks, restrictions, or blockages in the sensor or the pipes. Proceed to Test Step 5.
5. Check the NRS Temperature Sensor For a C4.4 engine, refer to Illustration 1. For a C6.6 engine, refer to Illustration 2. A. Remove temperature sensor (1) from NRS mixer (2). Refer to Disassembly and Assembly, "Temperature Sensor (Cooled Exhaust Gas) - Remove and Install". B. Check the sensor probe for excessive deposits. C. Test the exhaust back pressure regulator. Refer to Troubleshooting, "Motorized Valve - Test".	Temperature sensor	Result: The probe on the temperature sensor has excessive deposits. Repair: Carefully remove the deposits from the sensor probe. Make sure that the sensor probe is not damaged. If the deposits cannot be easily removed, replace the temperature sensor. Refer to Disassembly and Assembly, "Temperature Sensor (Cooled Exhaust Gas) - Remove and Install". Result: The probe on the temperature sensor does not have excessive deposits. Proceed to Test Step 6.
6. Inspect the NRS Mixer A. Inspect the NRS mixer for cracks, holes, or damage.	NRS mixer	Result: The NRS mixer is defective. Repair: Replace the NRS mixer. Refer to Disassembly and Assembly, "Inlet Air Control - Remove" and Disassembly and Assembly, "Inlet Air Control - Install". Result: There are no visible faults on the NRS mixer. Contact the Dealer Solutions Network (DSN).