A quick tour through Freightliner´s message ECU 128

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Once in a while, we are surprised by an indicator light flashing on the instrument panel without prior notice. For better interaction between the vehicle and the user, car manufacturers have included different ways to interact and inform the driver regarding any problem in a specific device or system and be able to locate it. In the case of Daimler and its Freightliner truck division, there is a message to alert when the vehicle detects a fault in the electronic engine control system: "ECU 1282". But what really mean?

(Source - https://www.justanswer.com/medium-and-heavy-truck/hbof6-ecu-128-code-2005-freightliner-truck.html)

  1. ECU 128, What are we dealing with?
  2. Fault Codes
  3. Conclusion

1. ECU 128, What are we dealing with?

ECU 128 message is displayed on the dashboard screen once a malfunction is identified in any element of the engine's electronic control system by the ECU. The principal function of this system is to verify the correct operation of the power unit, compiling all the information gathered by the sensors to convert them into electrical signals and share them to the electronic control unit, which processes and in turn sends information to the various actuators of the engine.

When the control unit does not receive any information from the sensors that record the operating conditions, it communicates a warning signal to the user indicating an issue in the engine.

Electronic control system failures are caused by different reasons. Primary causes are vibrations caused by faulty installation, overheating, deterioration of the components, and voltage overload related to a short circuit.

(Source - http://www.detroitmanuals.info/mbe900-mbe4000-egr/7b0900.html)

2. Fault Codes

To have a better understanding of the specific problem that our vehicle is experiencing, it is necessary to obtain the complete fault code. This code is composed of different identifiers that indicate the malfunctioning components. For example:

Code: 128 001 06

Message SID (Subsystem Indicator) Trouble
128 001 06

In this case, it indicates a problem in subsystem 001 (Cylinder No. 1 injector) and fault 05 (Cylinder No. 1 injector short circuit).

The most common subsystem indicators are:

001-006: Cylinder Injector

021: Crankshaft position sensor

039: Engine Starter Relay

045: Intake air heater

064: Camshaft position

084: Vehicle speed sensor

091: Accelerator pedal position

098: Oil level

100: Oil pressure

102: Charge air pressure

110: Coolant temperature sensor

168: Battery voltage

(Source - https://www.transportelatino.net/2013/12/freightliner-m2-106112-business-class-de-primera)


It is recommended to go to the authorized service center as soon as possible after this message is presented, where the complete fault code can be obtained and can be guided by specialized technicians. If you want to repair yourself, there are manual procedures in the dashboard interface to obtain this code, depending on the model of truck you own or with the help of specific scanners and tools.