Understanding Dual Hall-Effect Throttle Assemblies

More reliable sensor type/design - Hall effect devices used in motion sensing and motion limit switches can offer enhanced reliability in extreme environments.

There are no contacting moving parts involved within the sensor or magnet,

No idle validation circuit Eliminates throttle calibration

requirements following a throttle or ECM replacement

When electrons flow through a conductor, a magnetic field is produced.

A sensor voltage is applied across two terminals and the third provides a voltage proportional to the current being sensed.

Hall effect devices produce a very low signal level and thus require amplification.

Many devices now sold as "Hall effect sensors" contain both the sensor described above and a high gain integrated circuit amplifier in a single package.

Not a Dual Potentiometer

Never Ready

Applied Voltage

Hall Element/Device

(Semiconductor)

Lines of Magnetism (Flux Lines)

+

- Hall Voltage

There are many different Hall effect throttle types available

The following slide is intended to illustrate one possible type.

+ -

Movement of the shield disrupts the magnetic field and reduces the field strength seen by the Hall effect device.

The shield is connected to the throttle pedal.

Mag

netic F

ield

VDC

+-

The Hall effect device contains special circuits that produce an inversely proportional voltage and then amplify the small voltage into one that can be used by the ECM. If we were to take a measurement at the Hall element itself, the voltage would be reduced as the shield goes further into the magnetic field.

Hall Effect Device

4.75

Shield

Hall Effect Element

3.252.501.250.750.25

Hall Effect Device

Hall Effect Element

Inside a Hall Device

Primary sensor signal voltages 0.25 - 4.75 VDC

Used by the ECM to determine throttle pedal position

Spare sensor – rather than idle validation (set to a pre-determined throttle value) allows the vehicle to operate normally (slight derate)

Second sensor signal is only half or the primary throttle voltage range (0.25 to 2.375 VDC)

Why? Allows the ECM to determine a primary throttle sensor circuit issue when the primary and secondary voltage ratios do not match

Must be wired on a different sensor supply & return than the primary throttle sensor

No need to calibrate replacement throttle assembly

Wrong throttle type (with idle validation) installed will generate a fault code

Other Fault Codes