Turbocharger Electric Stepper Motor Actuators

What are Turbocharger Electric Stepper Motor Actuators ?

Stepper Motor Actuators on Turbochargers


Turbocharger Electric Stepper Motor Actuators facilitate excitor ring movement inside a VNT turbocharger.
Ring movement translates into mechanical movement of variable vanes inside the turbine housing of the turbo.
The vanes act in a similar way to a pneumatic actuated turbo dump valve on a standard turbocharger.
They facilitate build up pressure for boost and then release of gasses via vane movement (dump).

Do You Need to ‘Calibrate’ Electronic Stepper Motor?

Not all turbochargers with stepper motors allow physical, manual ‘calibration’.
This discussion relates mostly to the Toyota Hilux, Prado and Hiace. They run 1KD-FTV 3.0L turbocharged diesel engines that are easily calibrated.
Below at the bottom of this page, you will find links to the turbos and stepper motors for these models.
We sell cost-effective aftermarket, OEM alternatives, either as stepper only or turbocharger without stepper..
Alternatively, we have listed a range of complete units where stepper motors are already attached.
These are flow tested units, where the electric stepper motor is calibrated at the factory.
And when sold together, a substantial discount is applied over a separate component purchase.

The availability of separate components is new to the market.
Toyota OEM only sells the complete units. However, you may only need to replace either component, so it makes sense to replace only what is at fault.

To install a stepper motor onto a 1KDFTV turbocharger you just have 3 bolts to put tighten. And additionally, a clip for the actuator where it attaches to the vane lever.

After attaching turbocharger electric stepper motor actuators to the turbo, there is no need for any adjustment in most cases.
But in the occasional case, manual ‘calibration’ could be required.

Physical ‘calibration’ is likely required when issues persist:
Fault code(s) relating to Stepper Motor persist after clearing of previous codes.
e.g. CODE:P0047 indicating low volt or boost pressure out of correct range (usually low)
OR CODE:P1250 usually too high boost pressure.
– Vehicle is still sluggish or over-boosting fault codes are produced.
In such circumstances, limp mode may be activated by the ECU to protect the engine.

How Do You ‘Calibrate’ Turbocharger Electric Stepper Motor Actuators?

The job of the stepper motor is to provide correct boost across engine revs.
It actuates correct range of movement in actuator arm. Translating to nozzle ring movement and hence, vane opening and closing.

To calibrate, adjust the stopper bolt situated next to the actuator lever.
Adjustments will create either more or less movement in the actuator arm.
Make each adjustment in increments of 1/16 of a full screw turn.
After each small adjustment, test boost over revs.

What if the above doesn’t work?

When fault codes persist after the above has been done, you may need to:

Firstly, check for free movement of the actuator lever on the turbo.
You should be able to move it left-to-right with one finger and with little pressure. If it is stuck or gritty, there is likely excess particulates accumulated in the ring assembly.
This build-up is often due to poor combustion, so things like injector seals etc, should be checked.
The above can be mistaken for a stepper motor problem, so it is a good idea to check this first (also as an easy first step diagnostic).
If excess coking is found, also make sure the exhaust manifold is cleaned, to stop introduction of more debris into the turbine housing and ring assembly.

Then check:
– Correct function in the EGR valve. It should be clean, and not seized.
– AFM sensor function. Clean with electric contact cleaner or replace if an engine code relating to MAF is thrown and cleaning does not work.
– Correct function of the vehicle’s ECU.
– Correct function of the ECU responsible for boost control.
– Check all turbo and air/gas fittings: gaskets,pipes,clamps,air filter and housing and snorkel(if fitted).

How Can I Purchase Stepper Motors Separately?

Here is a list of cost-effective aftermarket turbocharger electric stepper motor actuators we have in stock at the best prices, covered by our Exclusive 24 Month Warranty.

Alternatively, here is our range of complete factory-calibrated (flow tested) units with stepper motors attached.
We have ceramic and high-flow billet upgrades that we hold in stock, and reco units at the best prices, also covered by our Exclusive 24 Month Warranty.

If you need any further information, or help in matching parts to your vehicle, please contact our sales line: 0490059316.