Freightliner, a large truck manufacturer, distributes many models of trucks. Over long periods, owners or users of Freightliner trucks may experience problems with its the engine control module (ECM). Cat, Cummings and Detroit are manufacturers and distributors of Freightliner ECM units. The ECMmust perform optimally to maintain control of engine cooling, the electrical system and the fuel system.

1998 Century Freightliner

A 1998 Century Freightliner may experience symptoms that include starting difficulty, low voltage and harsh idling. High idling will make the truck shut off intermittently. For rebuilt motors, a service company should replace the fuel shutoff sensor and change the fuel line if necessary. Also, if you experience fuel surging with your Freightliner engine, you may see the fault code 254. All of these symptoms result from a broken pass-through connector or a bad solenoid on the injector, which causes the ECM to display an injector fault.

Diesel Engine Cooling

The ECM on some recreational vehicles equipped with a Cummins EPA 07 ISL engine is not programmed correctly. You can resolve this type of problem with a Cummins diagnostic program. Another performance issue with the ECM on XC, XCS and XB chassis models is a fine layer of oil mist deposits on the radiator, which results from the radiator and the engine crankcase breather tube sitting excessively close together.

Electrical System

Since 1998, the Freightliner's ECM enables the vehicle data computer (VDC) to read and store the vehicle mileage from the ECM. The ECM will also read starter problems for trucks with Cummins ISM engines and a VCL chassis built prior to August 2001. In addition, RV chassis trucks and kysor dash instrumentation -- built from January 1999 to August 2000 -- may have problematic air lines to the vehicle data computer.

Fuel System

Based on reports on the website FAQs, Freightliners built between May 1998 and November 2000 can exhibit incorrect fuel gauge readings. When the fuel tank is between one-quarter and one-half full, the fuel gauge has identified an incorrect level in many cases. In addition, fuel line problems trigger the ECM.