RADIATOR GP 7C4403 - Caterpillar

Refer to Table 3. Determine the appropriate procedure according to the values of the "Boost Pressure" and "Aftertreatment 1 Secondary Mass Air Flow". Be sure to use the results of Test Point 3 and Test Point 4 in order to determine the appropriate procedure.For example, the results of the test indicate the following conditions:
The "Boost Pressure" was within the acceptable range during Test Point 3 and Test Point 4.
The "Aftertreatment 1 Secondary Mass Air Flow" was above the acceptable range during Test Point 3 and above the acceptable range during Test Point 4.In this example, Procedure "C" applies.Expected Result:The results are not within the acceptable range. The appropriate procedure was identified.Results:
The results are not within the acceptable range. The appropriate procedure was identified. - Perform the appropriate procedure.
The results are within the acceptable range. You are not troubleshooting a 3473-31 diagnostic code. - Proceed to Test Step 7.
The results are within the acceptable range. You are troubleshooting a 3474-31 diagnostic code. - Proceed to Test Step 8.Test Step 4. Procedure "A"
Illustration 3 g01443828
Inspection points for the line between the air pressure control valve and the venturi
A typical configuration is shown.
Refer to Illustration 3. Inspect the line between the air pressure control valve and the venturi. Look for these problems: cracked lines and loose hardware. Make the necessary repairs.
Run the "Engine Air System Verification Test" again.Expected Result:The results for Test Point 3 and Test Point 4 are within the acceptable range.Results:
The results for Test Point 3 and Test Point 4 are within the acceptable range. - If you are not troubleshooting a 3474-31 code, proceed to Test Step 7. If you are troubleshooting a 3474-31 code, proceed to Test Step 8.Test Step 5. Procedure "B"
Replace air pressure control valve (5).
Run the "Engine Air System Verification Test" again.Expected Result:The results for Test Point 3 and Test Point 4 are within the acceptable range.Results:
The results for Test Point 3 and Test Point 4 are within the acceptable range. - If you are not troubleshooting a 3474-31 code, proceed to Test Step 7. If you are troubleshooting a 3474-31 code, proceed to Test Step 8.Test Step 6. Procedure "C"Note: A small leak in the combustion air system can cause problems. Therefore, the combustion air system must be carefully inspected. Arrows in the illustrations indicate the inspection points.
Illustration 4 g01443835
Inspection points for the tubing between the venturi and the sensor
A typical configuration is shown.
Refer to Illustration 4. Carefully inspect the tubing between the venturi and the sensor by using the following procedure:
Inspect the flexible hoses. Look for these problems: holes, cuts and other damage.
Verify that all of the worm drive band type clamps are tight.
Verify that all of the line nuts on the venturi are tight.
If no problems are found, remove the differential pressure sensor from the engine.
Illustration 5 g01409818
Fillets on the hose barb couplers
Refer to Illustration 5. Inspect the fillets at the base of the hose barb couplers. Look for cracks.If there are cracks, replace the sensor.If there are no cracks, install the sensor.
Verify that