How to bench test typical Electric Power Steering (EPS) ECU?

To measure the output of the EPS ECU, you can consider measuring the current and voltage at the output of the motor controlled by the PWM output. Additionally, you may also want to measure the PWM duty cycle and frequency to verify that they match the expected values based on the inputs applied to the ECU.
If you are only planning to use a PIC microcontroller to emulate the TAS and a power supply, you may not need a load at the output. However, if you want to verify the performance of the ECU under different load conditions, you may want to connect a load such as a motor or an inductive load.
If you do decide to use a load, you can measure the parameters such as current, voltage, and power at the load. These measurements can be made using appropriate instruments such as a multimeter or an oscilloscope. You should also measure the output of the PWM signal at the input to the motor or load to ensure that the ECU is providing the desired control signal.
If you don't use a load, you can still measure the current and voltage at the output of the ECU to verify that the software is processing the inputs correctly. You can also measure the PWM duty cycle and frequency to ensure that they match the expected values based on the inputs applied to the ECU. These measurements can be made using appropriate instruments such as a multimeter or an oscilloscope.