Do not perform any procedures in this Troubleshooting Guide until the Operation and Maintenance Manual has been read and understood. Only use correct tools and observe all precautions that pertain to the use of those tools. Failure to follow these procedures can result in personal injury. The following procedures must also be adhered to.
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 to perform these functions correctly.
Safety precautions and warnings are provided in this publication and on the product. If these hazard warnings are not heeded, bodily injury or death could occur. 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.
These engines are equipped with an electronic control system. The system consists of a computer, sensors, actuators, and software. The system performs these functions:
- Control of the engine
- Control of particulate emissions via the Clean Emission Module (CEM)
- Applications control system interface
- Fault detection and reporting
The Electronic Control Module (ECM) is a computer that controls the operation of the engine.
The ECM contains a flash file. The flash file is the software for the ECM. The flash file contains the operating maps. The operating maps define the following characteristics of the engine:
- Horsepower
- Torque curves
- Engine speed (rpm)
Refer to Troubleshooting, "System Overview" for additional information on the electronic control system.
The ECM interfaces with the machine via software and an electrical connector on the ECM. The software can be configured.
The application control system provides inputs to the electrical connector on the ECM to indicate the status of switches. Correctly configure the ECM to interpret the inputs.
The ECM provides outputs for the application control system via the electrical connector to control lamps, solenoids, and other devices. Correctly configure the ECM in order for the outputs to match the configuration of the application control system.
The CEM contains these components:
Diesel Particulate Filter (DPF) - A DPF is installed in the exhaust system. The DPF collects soot and ash from the engine exhaust.
Diesel Oxidation Catalyst (DOC) - A DOC is installed in the exhaust system. The DOC oxidizes hydrocarbons (HC), carbon monoxide (CO), odor causing compounds, and soluble organic fractions (SOF).
Aftertreatment Regeneration Device (ARD) - The ARD provides more heat to convert the soot in the DPF into gas. The ARD operates only when more heat in the exhaust is needed.
Software - Software in the ECM monitors the DPF and the ARD. The software controls the delivery of fuel, combustion air, and the spark to the ARD.
The ECM monitors inputs from the sensors and inputs from the applications control system. Software in the ECM interprets the inputs. The software determines if the inputs are operating correctly. A diagnostic trouble code is activated when the software detects a problem with an input.
The ECM broadcasts the codes on two data links. The data links are the Cat Data Link (CDL) and J1939. The electronic service tool must communicate on both data links to service the engine. If a problem is suspected with one of the data links, refer to Troubleshooting, "CAN Data Link - Test" and Troubleshooting, "Data Link - Test" .
The codes can be displayed on the electronic service tool and optional operator interfaces. Refer to Troubleshooting, "Diagnostic Trouble Codes" for additional information on diagnostic trouble codes and a complete list of codes.
As a reference, simplified schematics for each of the engine subsystems may be included with each of the circuit tests that are in this manual. For an accurate representation of the entire electrical schematic that is for your application, refer to the Electrical System Schematic.
During troubleshooting, inspect all harness connections before any component is replaced. If these connections are not clean and tight, continuous electrical problems or intermittent electrical problems can result. Check that the wires are pushed into the connectors completely. Make sure that the connections are tight before other tests are made.
Failure of an electrical component may cause the failure of other components. Always attempt to correct the cause of an electrical failure before you replace a component. If wire insulation is punctured, repair the damage.
Troubleshooting Associated Codes
Certain systems will display multiple codes for troubleshooting . The "Associated Codes" must be used to troubleshoot the system. The codes should be viewed as separate levels of troubleshooting. For example, a "High DPF #1 Soot Loading" code is generated if the engine is allowed to run after an ARD warning is displayed. This main code is not the code that requires troubleshooting.
The system is designed to display the codes for this separate level of troubleshooting as an "Associated Code". The "Associated Code" is the diagnostic or the event code that needs to have the troubleshooting procedure followed.
The following paragraph is an example of troubleshooting the engine system with "Associated Codes".
After connecting the electronic service tool to an engine, the following codes are displayed:
- High DPF #1 Soot Loading
- Aftertreatment Insufficient Temperature to Complete Regeneration
- Aftertreatment Fuel Injector #1 not responding
These codes are the result of a fouled nozzle. The regeneration system was unable to increase the exhaust gas temperature enough to regenerate the trap because the fittings or the nozzle failed. The "High DPF #1 Soot Loading" code was generated because the trap was unable to regenerate. The troubleshooting procedure to use in this case is the "Aftertreatment Fuel Injector #1 not responding" code, which will fix the other two issues.