Diesel Particulate Filter Monitoring System {108F, 7490} Caterpillar

Diesel Particulate Filter Monitoring System {108F, 7490}


D3400 01T

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Diesel Particulate Filter Monitoring System {108F, 7490} Diesel Particulate Filter Monitoring System {108F, 7490}

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This Special Instruction provides information for the installation of the Diesel Particulate Filter Monitoring System.

System Description

The Diesel Particulate Filter (DPF) is placed on the engine in order to remove the soot and any particulate matter from the engine exhaust. A diagnostic module kit is also provided, and must be installed on the vehicle in order to properly monitor DPF health and functionality.

Note: The diagnostic module kit is a required component of the DPF.

The system monitors engine back pressure and exhaust temperature. The system also provides information to the driver and maintenance personnel on the performance of the DPF.

The Diagnostic Module (DM) monitors and records levels of the exhaust back pressure and the exhaust temperature entering the Diesel Oxidation Catalyst module of the DPF. Data is recorded to permanent memory. The operator can download data. The operator can review data in order to determine functional history and maintenance history. Alarm levels can also be set to record incidents of excessive back pressure, excessive exhaust temperature, or other system failures. The system will allow the warning diagnostic lights to be illuminated in order to alert the operator of system problems.

Important Safety Information

Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools in order to perform these functions properly. Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If a tool, a procedure, a work method or operating technique that is not specifically recommended by Caterpillar is used, you must ensure that it is safe for you and for other people to use. You should ensure that the product will not be damaged or the product will not be made unsafe by the operation, lubrication, maintenance or the repair procedures that are used.

------ WARNING! ------

Accidental engine starting can cause injury or death to personnel working on the equipment.

To avoid accidental engine starting, disconnect the battery cable from the negative (−) battery terminal. Completely tape all metal surfaces of the disconnected battery cable end in order to prevent contact with other metal surfaces which could activate the engine electrical system.

Place a Do Not Operate tag at the Start/Stop switch location to inform personnel that the equipment is being worked on.

------ WARNING! ------

Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact the skin.

------ WARNING! ------

Personal injury or death can result from improper assembly procedures.

Do not attempt any assembly until you have read and understand the assembly instructions.

Parts List

Table 1 refers to the required parts for the DPF Diagnostic Module Installation & Configuration.

Table 1
Required Parts
286-5247 Pressure Monitor Kit 
Part Number  Description  Quantity 
274-7578  Electronic Control Module 
286-5249  Hose--Pressure 914 mm (36 inch) 
307-5521  Wiring Harness 
271-7350  Lamp Ground 
280-3921  Temperature Sensor 
286-5248  Pressure Sensor 
8C-5607  Mounts -- Rubber 
8C-5608  Spacers 
9X-6165  Washer 
8C-8451  Bolt 

The following additional materials may be required for installation of the DPF:

  • Zip Ties

  • 15 Amp Fuse

System Components

Illustration 1 refers to the basic layout of a CaterpillarDiagnostic Module (DM).

Illustration 1g01340823
Basic Layout of Caterpillar DM
(1) LED Panel
(3) Pressure Sensor
(4) Temperature Sensor
(5) ECM

ECM Programming

The ECM is flash programmed via the Customer Data Link (CDL) with the service tool.

ECM Key Switch

The ECM Key Switch provides the ability to shut down the ECM via a low current switch. The ECM Key Switch also increases the life of the batteries by shutting the ECM off. The Key Switch also allows operators to remotely power off the ECM. The key switch controls when the ECM powers up. With the keyswitch "OFF", the current draw for the ECM will not exceed 10 mA.

ECM Connector

The ECM uses a 70 pin connector in order to connect to the OEM vehicle wiring harness. The torque for the ECM Connector should be 6 ± 1 N·m (4 ± 0.7 lb ft).

The Gauge for the ECM Connector

The battery positive connection and the battery negative connection must be made with 14 gauge SAE J1128 type GXL wire for the Deutsch stamped and formed terminal or the Deutsch solid terminal. All other connections may be 16 gauge or 18 gauge SAE J1128 type SXL or 14, 16, or 18 gauge SAE J1128 type GXL (or equivalent wire).

For most components on the engine, an 18 gauge has sufficient current capacity. Many applications will benefit from the increased reliability and the increased durability of 16 gauge.

Terminal Connectors and Sealing Plugs for the ECM

Refer to Table 2 for the terminal and the part numbers for the plugs. All terminals that are used in the connector must be gold. Selective gold flash terminals may also be used.

Table 2
Description  Usage 
70 Terminal Plug, Keyed 2  ECM Connector Harness 
Sealing Plug 14 - 18 gauge  Unused Connector Slots 


  1. Identify a location for the 274-7578 Monitor Electronic Control Module.

    Note: For the dimensions of the 274-7578 Monitor Electronic Control Module, refer to Illustration 2.

    Illustration 2g01340837
    Dimensions of the ECM

  2. Mount the 274-7578 Monitor Electronic Control Module in a space that the ambient temperature is below 85 °C (185 °F), and is not directly exposed to high pressure steam cleaning, solvents, battery off gas, or electrical discharge.

  3. Locate the 274-7578 Monitor Electronic Control Module away from direct sources of heat.

    Note: The 274-7578 Monitor Electronic Control Module for the DPF is powered by either a +12 VDC or +24 VDC nominal battery.

    Refer to "Specifications" for the voltage limit for the 274-7578 Monitor Electronic Control Module.

  4. Mount the 274-7578 Monitor Electronic Control Module with the provided hardware. In order to provide proper vibration isolation, ensure that the 274-7578 Monitor Electronic Control Module is installed according to Illustration 3.

    Illustration 3g01340860
    Installation Diagram for the ECM

  5. Determine an acceptable routing for the exhaust pressure sensor hose that is provided. The purpose of the hose is to isolate the pressure sensor from high ambient temperature (> 125 °C (257 °F)) near the turbo and DPF.

  6. Route the hose away from the turbo and the DPF. The boss on the inlet head of the DPF must be located on the top half of the head (as determined during the DPF packaging definition), and the hose must be routed upward, away from the DPF, with no loops for condensation to collect. In this orientation, any moisture that accumulates in the hose will flow downward to the DPF.

  7. Install the hose into the tapped hole that is provided. Tighten the hose to 20 ± 1 N·m (14.75 ± 0.73 lb ft).

  8. Install the pressure sensor in a space that the ambient temperature is below 125 °C (257 °F) during normal vehicle operation.

  9. Install the pressure sensor into the end of the pressure hose. Tighten the pressure sensor to 16 ± 1 N·m (11.80 ± 0.73 lb ft). The sensor must be oriented as close to vertical as possible. The hose must be pointing downward.

  10. Use zip ties or P clips in order to secure the sensor in the proper orientation. Ensure that the sensor cannot bounce against the other components during vehicle operation. The sensor is secured by the hose on one end and the wires are secured on the other end.

  11. Determine an acceptable routing for the exhaust temperature sensor. Sensor boss location must be determined as part of the definition for DPF packaging.

  12. Apply high temperature thread compound (1E2078) to threads of the sensor. Install the temperature sensor into the port that is provided. Tighten the temperature sensor to 45 ± 5 N·m (33 ± 3.6 lb ft). Refer to Illustration 4.

    Illustration 4g01341045
    (6) Temperature Sensor
    (7) Pressure Sensor

  13. Mount the 271-7350 Warning Indicator Module Gp in a place that is easy to view. Ensure that the ambient temperature is below 45 °C (113 °F), and ensure that the Warning Indicator Module is not directly exposed to high pressure steam cleaning, solvents, the battery off gas, or electrical discharge.

    Note: The LED display panel may be installed in the cab of the vehicle.

Illustration 5g01341118
(8) LED display panel
(9) ECM

Installation for the Wiring Harness

The 274-7578 Monitor Electronic Control Module is provided with a 307-5521 Wire Harness.

  1. Connect the 70 pin AMP to the ECM using a 160-7690 Connector Plug As. Tighten the Connector Screw for the ECM to 6 ± 1 N·m (4 ± 0.73 lb ft).

  2. Locate a 12 VDC or 24 VDC power supply that is always available even when the key is turned "OFF".

  3. Connect the power wires from the wiring harness to the power supply. Install a 15 AMP fuse in this circuit. If an additional wire must be spliced, use a 14 gauge wire.

  4. Attach the appropriate connectors to the pressure sensor, the temperature sensor, and the lamp group.

    Note: The service tool that is used in this installation is Caterpillar Electronic Technician (CAT ET). The service tool connector is a 9 pin Deutsch connector that contains the CDL (Caterpillar Data Link)/ATA, CAN/J1939, and power. A connection from the 274-7578 Monitor Electronic Control Module to the PC requires a Caterpillar Communications adapter, which connects to the PC via a serial port.

    The service tool (CAT ET) supports the following functions:

    • Download and review active alarms and logged alarms

    • Clear active alarms

    • View the data in real time.

    • Flash the diagnostic module.

    • Provide the capability for the user to configure certain parameters.

Software Configuration

Refer to Systems Operation, Troubleshooting, Testing and Adjusting, KENR6695 for a description of controllable parameters and operation instructions.

Once the 274-7578 Monitor Electronic Control Modulehas power, the 274-7578 Monitor Electronic Control Module will begin monitoring the pressure sensors and the temperature sensors.

  1. Check whether CAT ET is configured with English or Metric units.

  2. Set CAT ET to Metric units if a Metric unit is not already selected.


Table 3
System Requirements 
Requirements for 12VDC or 24VDC System  Value  Notes 
Operating Voltage Minimum  +9V  Minimum continuous operating voltage without damage to the ECM 
Maximum Operating Voltage  +32V  Maximum continuous operating voltage without damage to the ECM 
The voltage is over the maximum voltage that is allowed (two minutes continuous).  +80V  At 25 °C (77 °F) 
Reverse Voltage (one hour)  -32V  At 85 °C (185 °F) 
Power up voltage for the ECM  +9V  The minimum voltage for the ECM to internally run. Operating the engine at this voltage will cause the damage to the ECM. 
The maximum current draw with key switch off  10mA   
Maximum current draw with zero engine speed and no loads being driven  500mA   
Maximum continuous operating current draw  10A  This highly dependent upon the number and type of loads driven by the ECM 
Recommended size for the Battery Fuse.  15A   

Table 4
Operating Conditions 
Thermal Conditions  Vibrations  Humidity Tolerance  Salt Spray Tolerance  Moisture Leakage  Chemical Splash Immunity  Electrostatic Environment 
Operating Temperature Range: −40 °C (−40 °F) to 85 °C (185 °F)
Storage Temperature Range (Normal) −50 °C (−58 °F) to 120 °C (248 °F) 
9.80 grams random vibration from 24-2000 HZ in three orthogonal planes  115% Normal System Voltage (NSV), 90% relative humidity over the operating temperature range  115% NSV with 5% salt spray for 48 hours at 35 °C (95 °F)  35 kPa (5.1 psi) or −35 kPa (−5.1 psi) against water and water vapor  Diesel fuel, engine oil, machine oil, and SAE J1455 chemical agents  Zero damage during exposure to the electrostatic painting process. 


Diesel Particulate Filter Monitoring System Wiring Schematic

Illustration 6g01337616

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