Eastern turbo logo

Actuator Testing & Replacement

The function of the electronic actuator (stepper motor) is to move the nozzle ring assembly vanes in the turbocharger to control exhaust gas flow to match the desired boost requirements of the engine.   The calibration settings are programmed into the software within the black caps and are unique to each turbocharger.

It is possible that at times these units may become damaged and require replacement.  If this is the case, we recommend replacing the whole unit, rather than attempting a repair, as they are complex unitsand if not done correctly will only cause more issues and frustration and not solve your issue.

Most diagnostic tools used by mechanics today will be able to point toward a fault code that may be attributed to the actuator.  These codes may vary but will indicate things like “intermittent boost, low voltage boost pressure or out of range” and vehicle may go into limp mode. However, it is also important to note that these can also be “false codes” that in fact relate to other areas of the engine; some of the following can also trigger these codes that Indicate FAULTY ACTUATOR/STEPPER MOTOR –

  • Air Mass sensors may be faulty
  • Split intercoolers and/or hoses
  • Leaking exhaust manifold
  • Turbo to exhaust manifold leaks
  • Vacuum Solenoid defective
  • Worn or damaged wiring
  • Excessive load on VNT mechanism on turbo due to carbon build-up

We test the actuator (stepper motor) and turbocharger together using a VNT Flow Bench to see whether they are operating to OEM specifications and/or identify which component may be causing the issue.

If the actuator is faulty we can source a replacement unit (depending on availability) and calibrate it to your turbocharger so that it is set at the correct flow. 

NOTE:  When sending in your turbocharger unit please REMOVE and keep any hoses/pipes etc as these are not necessary for us and will not be returned.

It is important to note that not all actuators (stepper motors) are available as separate components and at times it may still be necessary to purchase a complete turbocharger. You can find this out by calling us on 03 9729 1636.

There are some actuators (stepper motors) that do not necessarily require calibration and can be replaced directly on the turbocharger. These are generally the SREA actuators that have already been calibrated and can be supplied for replacement.  There may however be instances where the replacement has not resolved the issue and in this case may require to be calibrated to the turbocharger.

When looking for a replacement actuator you will need to provide the part number of the turbocharger so that we can match the correct actuator to suit that application.

Please call us to discuss any questions you may have prior to sourcing a replacement actuator.