Do not perform any procedures in this Troubleshooting Guide until you have read the Operation and Maintenance Manual and you understand this information. Use only proper 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 should also be observed.
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 publication 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.
These engines are equipped with an electronic control system. The system consists of a computer, sensors, and software. The system performs these functions:
- Control of the engine
- Control of particulate emissions via the aftertreatment system
- 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 aftertreatment system contains the following components:
Diesel Oxidation Catalyst (DOC) - The DOC is a device in the exhaust system that oxidizes certain elements in the exhaust gases. These elements can include carbon monoxide (CO), hydrocarbons and the soluble organic fractions (SOF) of particulate matter.
Selective Catalytic Reduction (SCR) Catalyst - SCR is a process for reducing the oxides of nitrogen (NOx) in the exhaust gases. Ammonia is introduced into the exhaust and reacts with the exhaust gases in the SCR catalyst to convert the NOx into nitrogen and water vapor.
Diesel Exhaust Fluid (DEF) System - DEF is a mixture of urea and water that is injected into the exhaust stream. The heat in the exhaust gas releases the ammonia in the DEF. The ammonia reacts with the oxides of nitrogen (NOx) in the SCR filter to produce nitrogen and water vapor.
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 in order to indicate the status of switches. Correctly configure the ECM in order to interpret the inputs.
The ECM provides outputs for the application control system via the electrical connector in order 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 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 the J1939 CAN data link. If a problem is suspected with the data link, refer to Troubleshooting, "CAN 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 are 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. Seal the damaged wires with 8T-0065 Silicone Sealant. Cover the sealant with two layers of 1P-0810 Electrical Tape.