Efficient OBD FailureSimulation

ASM Box:

Efficient OBD calibration

>> Easy modulation of almost every signal – from injection parameters to NOx or particle sensors: The ASM Box is a milestone in vehicle homologation and PVE <<

During vehicle homologation, the correct functioning of the engine diagnosis functions need to be demonstrated. For this increasingly complex fault scenarios need to be identified. Realizing these failure patterns using faulty hardware is inflexible and requires a high effort. An alternative consists of manipulating the software calibration itself, which, however, is prohibited in some countries (USA/CARB) during homologation.

The modulation of electrical signals that are exchanged between the actuators/sensors and ECU represents another solution for generating realistic failure patterns in the engine and exhaust system. For this purpose the TOPEXPERT ASM Box (Actuator Sensor signal Modulation Box) has been developed. With its ruggedized electronics and housing, the system is designed for in-vehicle use and applications close to the engine. The ASM Box can modulate basic analog and digital as well as PWM signals. H-bridge circuits are available to drive actuators like an electronic throttle. For interaction with new generation smart sensors and actuators, CAN, LIN and SENT (J2716) interfaces are provided. The ASM Box also features the modulation of injection, crankshaft sensor and ignition signals. This enables the realization of complex injection fault patterns like cylinder-specific AFR deviations or misfires. Up to 5 injections can be controlled individually with respect to timing and quantity. A Break-Out-Box is used to conveniently connect the sensors and actuators. Replaceable loads to emulate the behavior of the actuators to the ECU are provided.

The Matlab/Simulink toolkit delivered with the system provides block libraries for setting up arbitrary fault simulation models which can be compiled and downloaded to the box. An XCP over CAN interface enables comfortable access by standard calibration tools.

The ASM Box inside the vehicle
Verification of PVE and OBD calibration
Actuator and sensor signal modulation
Fields of application

ASM Box Case

The ASM Box - Motorcycle, Misfire, and Compact are supplied as standard in a waterproof case including all associated modules and cables. There is no standard case for the ASM Box - solenoid and piezo, but it is possible to order a suitcase separately.


  • Injection signal modulation for solenoid and piezo injectors
  • Ignition signal modulation
  • Oxygen sensor signal modulation
  • Crankshaft sensor signal modulation
  • SENT, LIN and CAN message modulation
  • Base set of failure models included
  • XCP-access for comfortable parameterization of failure models


  • One hardware covering nearly all failure patterns
  • Easy realization of complex misfire scenarios including
  • Injection turn-off
  • Hiding of injection events
  • Changing start of injection and injection duration
  • Ignition turn-off
  • Convenient handling by versatile breakout box
  • Full flexibility by bespoke failure pattern development in Matlab/Simulink®