Measures driver-applied steering torque for electric power-steering assistance.
SENSOR GUIDE26/86
Identify the circuit first
ONE NAME. DIFFERENT SIGNALS.
Pin count is a clue, not proof. Confirm the exact architecture before resistance testing, applying voltage or judging the waveform.
TYPE 01CONSTRUCTION VARIANT
Dual analog torque tracks
Confirm wiring, pin count and service information before testing.
Two centered analog tracks move in opposite directions as the torsion bar twists.
Reading the signal
Good waveform
The measured signal changes consistently with the physical input and stays within the application-specific operating range. Under a steady input, it should remain stable apart from normal noise or control activity.
Faulty waveform
Dropouts, unexpected spikes, a signal pinned near a supply rail, or a biased reading can indicate a problem. Verify the real input, reference and loaded ground before blaming the sensor; a smooth signal can still be inaccurate.
TYPE-SPECIFIC TESTS
+ Scope both tracks simultaneously; verify smooth travel and the specified relationship.
+ Verify the specified supply, ground, bias or termination before judging the signal.
+ Repeat the test through the complete operating range.
EXPECTED
✓ Output matches this construction type
✓ Stable levels and repeatable response
✓ Agreement with related scan data
COMMON FAULTS
— Incorrect test method for the sensor type
— Supply, ground or signal-circuit fault
— Installation, target or calibration concern
TYPE 02CONSTRUCTION VARIANT
Contactless magnetic torque tracks
Confirm wiring, pin count and service information before testing.
Magnetic sensing elements measure torsion-bar twist through redundant analog or PWM outputs.
Reading the signal
Good waveform
Compare the measured signal with the specified input or command under the same operating conditions. Levels, timing and repeatability should match the installed design and a suitable verified reference. There is no universal waveform or scale for every version of this component.
Faulty waveform
An unexplained dropout, missing response, excessive noise or mismatch between command and feedback warrants further testing. First rule out a changed physical condition, incorrect probe reference, supply loss and an unsuitable scope setting; an unusual trace alone does not identify a failed component.
TYPE-SPECIFIC TESTS
+ Verify both supplies and grounds, then graph both channels together through full travel.
+ Verify the specified supply, ground, bias or termination before judging the signal.
+ Repeat the test through the complete operating range.
EXPECTED
✓ Output matches this construction type
✓ Stable levels and repeatable response
✓ Agreement with related scan data
COMMON FAULTS
— Incorrect test method for the sensor type
— Supply, ground or signal-circuit fault
— Installation, target or calibration concern
TYPE 03CONSTRUCTION VARIANT
SENT or networked position
Confirm wiring, pin count and service information before testing.
A local sensor encodes position digitally or the actuator module reports calculated position.
Reading the signal
Good waveform
Check the correct physical interface and decode the transmitted data. Valid frames, expected update timing and measurements that agree with the real input support normal operation. Pulse shape alone does not establish measurement accuracy.
Faulty waveform
Corrupted or missing frames, unexpected pauses, invalid status bits or implausible decoded values can indicate a fault. Verify supply, ground and the applicable bus before replacing the sensor; do not apply CAN waveform expectations to LIN, SENT or another interface.
TYPE-SPECIFIC TESTS
+ Check timing/network integrity and compare command, both internal tracks and calculated position.
+ Verify the specified supply, ground, bias or termination before judging the signal.
+ Repeat the test through the complete operating range.
EXPECTED
✓ Output matches this construction type
✓ Stable levels and repeatable response
✓ Agreement with related scan data
COMMON FAULTS
— Incorrect test method for the sensor type
— Supply, ground or signal-circuit fault
— Installation, target or calibration concern
Correct theory and operation
HOW IT WORKS.
Understand the sensing method, circuit and controller strategy before interpreting data or replacing the component.
01
Measured condition
Measures driver-applied steering torque for electric power-steering assistance.
02
Signal type
Dual-channel plausibility signal. Two independent or inverse tracks let the controller compare demand and detect disagreement.
03
Controller use
The receiving controller checks range, rationality and rate of change against related inputs before setting a fault or substituting a value.
04
Installation matters
Mounting, target condition, air gap, contamination, temperature, shielding or calibration may affect the result even when the circuit is intact.
Common mistakes
AVOID THE FALSE CLUE.
Condemning the sensor before verifying powers, grounds and communication.
Using a generic value instead of vehicle-specific service information.
Checking an unloaded circuit that fails only while operating.
Ignoring mechanical, installation or calibration causes.
Replacing the component without repeating the original test.
COMPLETE TEST SEQUENCE
Graph both channels together through the complete travel range.
Verify shared and separate references and grounds.
Check that both tracks remain smooth and plausible.
Perform the specified calibration after circuit or mechanical work.
Repeat the original operating condition and confirm the repair.
DO NOT CONDEMN THE SENSOR
Prove its supply, ground, signal path, physical input and calibration before replacement. Vehicle-specific specifications always win.