KIT-PIN 1768271 - Caterpillar

Illustration 3 g03781041
NRS valve
(7) NRS actuator assembly
(8) NRS valve body
Illustration 4 g03781337
NRS valve
(9) Point of rotation
Table 5
Troubleshooting Test Steps Values Results
4. Inspect the NRS Valve
A. Remove actuator assembly from NRS valve body.
B. Use a straight screwdriver to rotate the valve inside the NRS valve body. The valve should freely rotate from the open to close positions for 90 degrees of rotation.
Valve Rotates Freely
Result: NRS valve does not rotate at all, or the valve is difficult to rotate.
Repair: Replace the NRS valve body and install the actuator assembly that was previously removed.
Reset all active codes and clear all logged codes by cycling the keyswitch to the Off position. Use Cat ET to perform an "EGR System Test" in order to verify that the problem is resolved.
Result: NRS valve does rotate freely from open to close.
Repair: Install new actuator assembly.
Reset all active codes and clear all logged codes by cycling the keyswitch to the Off position. Use Cat ET to perform an "EGR System Test" in order to verify that the problem is resolved.
Illustration 5 g03781343
Typical mounting locations for the NRS sensors
(10) NRS differential pressure sensor
(11) NRS absolute pressure sensor
(12) Mounting point for NRS differential pressure sensor
Table 6
Troubleshooting Test Steps Values Results
5. Inspect the Mounting Location for the NRS Differential Pressure Sensor
A. Refer to Troubleshooting, "Electrical Connectors - Inspect" when checking sensors.
B. Remove the NRS differential pressure sensor.
C. Inspect the mounting location for signs of accumulations of soot. The accumulation may indicate further accumulations of soot downstream in the pressure passages.
Soot Build-Up
Result: Soot build-up is evident in the NRS differential pressure sensor passages.
Repair: Remove the NRS venturi. Use hot soapy water and a bore brush to clean out the passages for the NRS venturi differential pressure.
Reset all active codes and clear all logged codes by cycling the keyswitch to the Off position. Use Cat ET to perform an "EGR System Test" in order to verify that the problem is resolved.
Result: Little or