Driveability - Non-Dtc Based Diagnostics - Diesel: Overview RAM Pickup 3500

Overview

This service document provides visual inspection guidelines for the aftertreatment systems used in Cummins 6.7L powered Dodge Ram vehicles. This includes both Pickup truck, model years 2007-Present (2500 & 3500 Series) and Cab Chassis model years 2007-2010 (4500 & 5500 Series). For removal and installation procedures, refer to appropriate ENGINE - SERVICE INFORMATION article . The Aftertreatment systems are uniquely different for the Pickup truck and Chassis Cab. Above are diagrams of both systems.

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1. PICKUP OR CAB CHASSIS VEHICLE Is the vehicle a Pickup or Cab Chassis frame? Pickup Go To 2 . Cab Chassis Go To 5 .
2. PICKUP VEHICLE INSPECTION OF THE DIESEL PARTICULATE FILTER (DPF) NOTE: The primary failure modes for the DPF are inlet face plugging, internal cracking and internal melting. Inlet face plugging is easily diagnosed. Internal cracking and melting can be identified by soot patterns on the DPF outlet and/or evidence of soot on the outlet tail pipe. Remove the DPF from the vehicle. Inspect the inlet face of the DPF. NOTE: DPF Inlet is the flanged side. This figure is an example of a failed DPF due to severe face plugging. All inlet channel openings are completely plugged. Symptoms would possibly include hard or no start and/or related P-codes. This figure is an example of a good DPF inlet. Note that immediately following a regeneration event, the inlet face will/may look cleaner. Also note that it is normal for the inlet face to be coated with soot. Inlet channels should be open and visible. As long as cell matrix is visible the inlet is ok. Inspect the outlet of the DPF. This figure is an example of a failed DPF due to an internal melting of cells. The DPF outlet face and pipe show evidence of soot. Symptoms can include Black Smoke, and/or related P-codes. This figure is an example of a failed DPF due to an internal cracking of the substrate. The DPF outlet channel openings show evidence of soot. Close inspection shows several blackened channel openings or black cells. Also Outlet pipe shows evidence of soot. Symptoms can include Black Smoke, and / or related P-codes. This figure is an example of a failed DPF due to a leak at the DPF Outlet rim of substrate. Look for black cells on the outlet face. This figure and the next are examples of a good DPF. In this figure, it is not black or does not show any black cells. Note orange appearance near weep hole at bottom. This is dirt ingestion from dusty areas that does not affect filter performance. Outlet pipe is not sooty as compared to a failed part. Normally outlet face is off white or tan in appearance. This figure shows an enlarged section with a small black circle near the center of substrate. This is the only sign of soot evident in the entire outlet inspection. A quick check with a 1 inch socket will show pass/fail of this part. Using a one inch socket (1.375 inches Outer Diameter) and extension, cover the black spot at the center of DPF outlet face. If the 1 inch socket covers the black spot and no other black cells are visible, DPF doesn't need to be replaced. If there are any black cells visible around the 1 inch socket, DPF does not meet pass criteria and should be replaced. If there are any black cells on other portions of the outlet face in addition to a black spot in the center, DPF should be replaced. NOTE: Make sure one inch socket has about 1.375 inches of outer diameter (Standard socket not impact). DPF outlet thermistor may be removed, if it is in the path of the black spot. Does the DPF show signs of face plugging, internal cracking or melting? Yes Replace the Diesel Particulate Filter in accordance with the service information. No Go To 3 .
3. INSPECTION OF THE NOx ABSORBER (NAC) ON A PICKUP NOTE: The primary failure modes for the DPF are inlet face plugging, cracking and internal melting. Inlet face plugging is easily diagnosed (would resemble the figure showing face plugging of the DPF). Remove the NAC from the vehicle for inspection. Inspect the inlet side of the NAC. This figure and the next are examples of a good NAC. The inlet shows no signs of face plugging, melted spots, or cracks on the face of the grid. A typical NAC inlet will be coated with soot. The inspection process is to verify that light can be seen through the cells. If light can be seen through the cell matrix then the part is good. This figure is a zoomed view to show a close sample of wash-coat spots. Typically the size of these spots are 3/16". These are not due to melting and does not require replacement. Does the NAC show signs of face plugging, internal cracking or melting? Yes Replace the NOx Absorber (NAC) in accordance with the service information. No Go To 4 .
4. INSPECTION OF THE DIESEL OXIDATION CATALYST (DOC) NOTE: The DOC inlet is the only portion that can be inspected easily. Key modes of failure are FACE plugging, debris and possibly melted channels. This figure is an example of a good DOC. Soot is present on the inlet which is normal. As long as cell matrix is visible the inlet is ok. Does the DOC show signs of face plugging, internal cracking or melting? Yes Replace the Diesel Oxidation Catalyst (DOC) in accordance with the service information. No Test complete.
5. CAB CHASSIS VEHICLE INSPECTION OF THE DOC/DPF (DIESEL OXIDATION CATALYST AND DIESEL PARTICULATE FILTER) NOTE: The inlet side to the DOC/DPF on the Cab Chassis is the Catalyst portion. It resembles the Pickup NAC in appearance. The outlet side is the Diesel Particulate Filter portion. This functions exactly the same as the DPF on the pickup truck. Because they are combined, only the inlet of the DOC and outlet of DPF on the cab chassis can be inspected. Remove the DOC/DPF from the vehicle for inspection. Inspect the DOC inlet. Look for signs of FACE plugging, debris and possibly melted channels. NOTE: The DOC inlet can be identified by a "diffuser" leading into the inlet. This figure and the next are examples of a good DOC. The inlet shows no signs of face plugging, melted spots, or cracks on the face of the grid. This figure is a zoomed view to show close up sample of wash-coat spots. Typically the size of these spots are 3/16". These are not due to melting and does not require replacement. Inspect the outlet of the DPF. This figure is an example of a failed DPF due to an internal melting of cells. The DPF outlet face and pipe show evidence of soot. Symptoms can include Black Smoke, and/or related P-codes. This figure is an example of a failed DPF due to an internal cracking of the substrate. The DPF outlet channel openings show evidence of soot. Close inspection shows several blackened channel openings or black cells. Also Outlet pipe shows evidence of soot. Symptoms can include Black Smoke, and / or related P-codes. This figure is an example of a failed DPF due to a leak at the DPF Outlet rim of substrate. Look for black cells on the outlet face. This figure and the next are examples of a good DPF. In this figure, it is not black or does not show any black cells. Note orange appearance near weep hole at bottom. This is dirt ingestion from dusty areas that does not affect filter performance. Outlet pipe is not sooty as compared to a failed part. Normally outlet face is off white or tan in appearance. This figure shows an enlarged section with a small black circle near the center of substrate. This is the only sign of soot evident in the entire outlet inspection. A quick check with a 1 inch socket will show pass/fail of this part. Using a one inch socket (1.375 inches Outer Diameter) and extension, cover the black spot at the center of DPF outlet face. If the 1 inch socket covers the black spot and no other black cells are visible, DPF doesn't need to be replaced. If there are any black cells visible around the 1 inch socket, DPF does not meet pass criteria and should be replaced. If there are any black cells on other portions of the outlet face in addition to a black spot in the center, DPF should be replaced. NOTE: Make sure one inch socket has about 1.375 inches of outer diameter (Standard socket not impact). DPF outlet thermistor may be removed, if it is in the path of the black spot. Does the DOC/DPF appear to be face plugged, melted or have any internal cracking? Yes Replace the DOC/DPF in accordance with the service information. No Test complete.

Theory of Operation

There are two purposes to this diagnostic test. The first purpose is to try to determine whether an engine misfire or rough running condition can be narrowed down to a specific cylinder or if it is due to a fuel, air handling, or exhaust system issue. The second purpose is to help the technician follow the correct path to diagnose and completely repair the system at fault.

This procedure explains the proper method for extracting a fuel sample and specific methods to inspect for contamination of any kind. The contamination we are looking for on the clean side of the Fuel Filter is very small. We don't say dirt because it may be metal, water, plastic or any other contamination, other than clean diesel fuel. The smallest we can see with naked eye is about 30 Microns. Our Fuel Filters have 5 Micron rating. The only way we can see this size of contamination is to properly collect it and view it. The fuel sample needs to be taken from the clean side of the system. In order to get a good clean side sample to inspect, perform the following procedure exactly.

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1. CLEAN SIDE DIESEL FUEL SAMPLE COLLECTION AND INSPECTION NOTE: The three photos in this test step illustrate the steps in this test procedure for clarification. 1. LED FLASHLIGHT 2. MEASURING CUP 3. SLOWLY TILT THE CUP TOWARD YOU NOTE: The fuel filter MUST NOT be removed or replaced prior to taking sample in order to get accurate results. NOTE: Warm the engine before collecting the fuel sample. Start the engine and using a scan tool, monitor the Coolant Temperature Sensor reading in Data Display. While the engine is warming up, clean the clear tubing with clean diesel fuel and the glass measuring cup using brake clean and compressed air only. Do not use a towel. NOTE: Do not use brake clean or other chemicals on any vehicle parts for the fuel handling system such as lines, pumps or fittings. Monitor the scan tool until the vehicle has reached an operating temperature of 180°F (82°C). Turn the engine off. Remove the HPDP return line quick disconnect from the fitting located at the front of the Fuel Filter housing at the banjo bolt joining the Pressure Limiting Valve return (Connection A in the fuel system connections figure above). NOTE: The fuel flowing from the return of the High Pressure Delivery Pump (HPDP) MUST NOT be part of our sample. We are looking primarily for injector return fuel. The easiest way is to eliminate the HPDP return line and pull the injector return flow sample from the filter mount, on the front side. 1. LED FLASHLIGHT POINTING THROUGH BOTTOM OF CUP (Shine Toward the Handle) 2. SLOWLY TILT THE CUP TOWARD YOU Cap off the male fitting that the HPDP return line was disconnected from. Disconnect the quick connect fitting for the fuel return line located on the back side of the Fuel Filter housing (Connection B in the fuel system connections figure above). Attach the four foot length of 5/16" clear tubing to this exposed male fitting and orientate it on a downhill angle in to a drain pan. This will be your sample source hose. Using a hose with two male fittings, attach one end to the HPDP return line disconnected in step 5. Connect the other end to the fuel return line disconnected in step 7. This will return the High Pressure Pump return flow back to the tank while collecting the sample. Start the engine, and continue monitoring the coolant temperature to maintain the 180°F (82°C). Using the scan tool, navigate to PCM > System Tests > Fuel Pressure Override Test and select start. Initiate the Fuel Pressure Override Test two consecutive times to further warm the fuel and allow the tubing to be thoroughly rinsed clean. Start the Fuel Pressure Override Test a third time. At mid stream of the test move the clear tube to the measuring cup. Collect a sample of approximately 1/4 inch of fuel in the measuring cup. Turn the engine off. 1. Contamination will gather at the trailing edge of fuel. VIEW CAREFULLY, LOOKING FOR VERY SMALL PARTICULATE MATTER (May Look Cloudy) NOTE: Follow these next steps exactly to inspect the sample for contamination. Allow the sample to sit for 10 minutes in a dust free environment to allow the debris to settle to the bottom. It is important to not allow any air born contaminates to get into the fuel sample. Do not shake, swirl, or agitate the fuel in any way. The contamination should settle to the bottom. Hold the measuring cup (2) by the handle in one hand and shine the LED flashlight (1) through the bottom of the container toward the handle of the cup. Slowly tilt the measuring cup (2) toward you and keep the LED flashlight (1) at the trailing edge of the fuel as it comes down the bottom of the cup and inspect for contamination. Any dirt in the fuel will collect and be pulled by this trailing edge of fuel (Number one in the last figure) . It may be any color and sometimes looks as though the fuel is cloudy. This is the contamination. . If you see ANYTHING AT ALL , the fuel is contaminated. View the following repair options: The fuel sample is found to be contaminated: To ensure that the In Tank Lift Pump is operating properly, perform the Lift Pump Flow Test. For instruction and specifications on this procedure, refer to the «CHECKING THE FUEL DELIVERY SYSTEM»(ref-457849-S04686286802012030200000) procedure, test step 5 . After checking the In Tank Lift Pump operation, perform the DIESEL FUEL SYSTEM CLEANING PROCEDURE. Refer to «DIESEL FUEL SYSTEM CLEANING PROCEDURE»(ref-457834-S22549319022012030200000) . Go To 2 . The Fuel sample is clean: Install new fuel filter and Mopar (CRC) fuel injector cleaner into the fuel tank at a ratio four times the recommend concentration. Go To 2 .
2. DIAGNOSTIC PATH Were you instructed to inspect for Fuel Contamination from the MIL LIGHT ON PRETEST PROCEDURE? Yes Perform the diagnostic trouble code test that was found to be present. Refer to «DIAGNOSTIC CODE INDEX»(ref-457920-S15845563662012030200000) . No Go To 3 .
3. DIAGNOSTIC PATH CONTINUED Were you instructed to inspect for Fuel Contamination from a Non-DTC TEST PROCEDURE? Yes Perform the DIESEL AFTERTREATMENT VALIDATION 6.7L procedure. Refer to «DIESEL AFTERTREATMENT VALIDATION- 6.7L»(ref-457925-S11842698782012030200000) . No Return to Diagnostic Test that directed you to inspect for fuel contamination.