Electronic control fuel injection system (Common rail type) 1E-15 Pre-inspection Trouble Diagnosis Visual inspection of engine compartment Visual inspection of engine compartment should be carefully when performing the diagnostic procedure. This inspection can often solve the trouble with no extra steps. If performing visual inspection, follow the guideline below. Check all the air hoses etc. for punch hole, cut, disconnection or improper routing. Inspect the hoses hidden behind other components.
Check if all the harnesses of the engine compartment are properly connected, if there are any burnout parts or worn parts, if harnesses are pinched, if there are any contacts with sharp edges, or an exhaust manifold or pipes in high temperature, etc. About diagnostic trouble code (DTC) Every time turning the key switch to ON, the ECM performs self-test of most wiring and components and stores the detected faults in memory. For some DTCs, it also performs the back-up control. If the fault which affects operation occurs, the diagnosis lamp comes on to notify an operator. Basic knowledge for required tools Important:
If performing the diagnostic procedure, no basic knowledge on this powertrain may lead to faulty diagnosis or damage to powertrain components. If you do not have basic knowledge, do not perform the diagnosis of the trouble relating to powertrain. Basic understanding on hand tools, such as scan tools, is required to utilize service manual effectively. Machine maintenance result check If the maintenance of the machine is not properly performed, the diagnosis lamp comes on. Clogging in oil filter or fuel filter caused by insufficient oil change or improper oil viscosity and deposit in crankcase may cause troubles on the machine, which were not found before on-board diagnosis (OBD) system check.
Though improper maintenance of the machine is not classified as “The trouble caused by other than a machine”, a maintenance schedule should be more strictly followed because of high sensitivity of the on- board diagnosis (OBD) system check. About on-board diagnosis test Types of trouble diagnosis results are the following. 1. History trouble Trouble codes which occurred under the following conditions are called “History trouble”. Diagnostic test was completed at previous ignition cycle. Diagnosis test has accepted at current ignition cycle. Faults found by the diagnostic test do not currently exist. 2.
Present trouble Trouble codes which occurred under the following conditions are called “Present trouble”. Diagnostic test was completed at previous ignition cycle. The faults detected by the diagnostic test currently exist. The faults exist at current ignition cycle. Non-OEM parts All the on-board diagnosis system checks are adjusted to be operated by genuine parts. Therefore, if a commercial general sensor or switch is installed, the diagnosis lamp comes on due to faulty diagnosis. If commercial electronic devices, such as mobile phone, stereo, antitheft device, etc.
are installed and their installation is not proper, EMI (electromagnetic interference) may be discharged to the control system. That leads to the generation of fault sensor information and the diagnosis lamp comes on. When performing trouble diagnosis, turn the power of all commercial parts to “OFF” or remove those parts, and check for faults again. Description of terms Ignition cycle Ignition cycle is defined as Key ON, Run and Key OFF so that the machine can be operated under the specified diagnostic standard. Information:
Fault in related system Diagnosis lamp Many on-board diagnosis (OBD) system checks enter the back-up operating mode by instruction from engine control module (ECM) when the ECM detects the fault in related systems or components. In the back-up operating mode, they lower output to protect the machine. Basically, the diagnosis lamp comes on when the fault occurs in electronic control, such as engine control module (ECM), and a DTC (diagnostic trouble code) is detected.