BUSHING 4F6949 - Caterpillar

This procedure covers the following diagnostic trouble code:
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.
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
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 sensorProbable Causes
Diagnostic codes
Electrical connectors and harness
Air inlet and exhaust system
NRS inlet pressure sensor and sensor pipes
NRS temperature sensor
NRS mixerRecommended Actions
Note: The procedures have been listed in order of probability. Complete the procedures in order.
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