Freightliner codes are obtained through diesel engine parts sites, such as DieselServiceParts.com. The site provides a long listing of codes that enable truckers and mechanics to diagnose a specific engine problem. The engine control module, or ECM, constantly tracks voltage signals and records codes when values do not meet with the standard set for a specific system or part.
Freightliner codes are categorized as inactive or active. If an error occurs but does not take place during diagnostic testing, it is referred to as an inactive fault. However, if the error occurs when a diagnosis is being made, it is considered an active fault. The status of a code is determined by an electronic service tool or by flash code activity.
Codes for diesel engines are represented by specific types of engines, namely ISB, ISC, ISL, ISM and ISX. Therefore, ISB fault codes may refer to parts for an ISB type engine, such as the ECM microprocessor -111 or the ESS circuit -115. The intake manifold pressure sensor circuit is designated by two codes, 122 and 123, and the coolant temperature sensor circuit has a 144 error code.
In addition to fault codes, diesel parts sites can provide engine specs and torque specs. Common failures occur the most often in sensors, fuel pumps and parts connected to the exhaust system in trucks.