PICANTO(SA) > 2010 > D 1.
1 TCI-U > Steering > MDPS > C1290 Torque Sensor Main
Signal-Open/Short
C1290 Torque Sensor Main Signal-Open/Short > General Information
Component Location
General Description
A torque sensor, installed in the middle of steering column, is one unit composed of a main sensor and sub sensor. When the
steering wheel is turned, the torsion bar is twisted in proportion to load of the wheel, and the assembled shaft turns as well. At this
moment, due to twist of shaft, a change in the magnetic field is generated in main sensor coil surrounds the shaft and in the sub-
sensor coil which is inside torque sensor. The change in current produced by this process is input to the EPS CM. With a change of
input sensor signal current, EPS CM determines driver’s steering direction then, comparing current differences between the two
sensors, the EPS CM determines whether main sensor is open/short. The Torque sensor can be damaged during disassembly of
the sensor. You must disassemble or remove the sensor when removing or replacing the assembly.
DTC Description
This DTC refers to open/short of singnal circuit of main torque sensor. This code is set if main sensor output signal current is too
high or low when torque sensor power is supplied normally. Due to this malfunction, DTC C1291 and C1292 can be set with this
DTC at the same time.
DTC Detecting Condition
Item Detecting Condition Possible cause
DTC strategy ● Current check
Enable conditions ● Torque sensor voltage ≥ 7.0 V
Threshold value ● Main sensor output > 9.4 mA or < 0.6 mA
● Open/short in main signal circuit
Diagnosis time ● 1sec ● Contact resistance in connections.
● Motor : OFF ● Faulty sensor
● Relay : OFF
fail safe
● Fail lamp : ON
● Restoration condition : Power "OFF"
Schematic Diagram
Signal Waveform
Fig.1) When turning steering wheel to right : Check whether signal voltage rises to maximum 4V based on 2.5V and main sensor
signal is the same as sub sensor signal. [Main sensor - Sub sensor] < 0.75 mA
Fig.2) When turning steering wheel to left : Check whether signal voltage descends to maximum 1V based on 2.5V and main
sensor signal is the same as sub sensor signal. [Main sensor - Sub sensor] < 0.75 mA
C1290 Torque Sensor Main Signal-Open/Short > Scantool Diagnostics > Monitor Scantool Data
Monitor Scantool Data
1. Connect scantool to Data Link Connector(DLC) and start engine.
2. Monitor the "STEERING WHEEL TORQUE" parameter on the scantool.
3. Operate the steering wheel to the left and right..
1) Specification : Approx. 9.0 Nm ~ 9.0 Nm ( ""means Turning steering wheel to left.)
Fig.1) Normal current data
Fig.2) Current characteristic chart
Check whether the target current magnitude is the same as the motor current magnitude, refer current characteristic chart
according to present the vehicle speed and the toque sensor.
4. Is parameter within specifications?
▶ Fault is intermittent and caused either by poor contact in connectors or wiring harness, or it has been repaired and EPS CM
memory is not cleared yet. Thoroughly check all connectors (and connections) for looseness, bending, corrosion, contamination,
deterioration, and/or damage.
▶Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
▶ Go to "W/Harness Inspection" procedure.
C1290 Torque Sensor Main Signal-Open/Short > Inspection/Repair > W/Harness Inspection
Terminal and Connector Inspection
1. Many malfunctions in the electrical system are caused by poor harness and terminals.
Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check all connectors (and connections) for looseness, bending, corrosion, contamination, deterioration, and/or
damage.
3. Has a problem been found?
▶ Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
▶ Go to "Signal Circuit Inspection" procedure.
Signal Circuit Inspection
1. Ignition "OFF"
2. Disconnect torque sensor connector and EPS CM connector.
3. Measure resistance between terminal "2"of torque sensor harness connector and terminal "5"of EPS CM harness connector.
1) Specification : Approx. 0 Ω
4. Is the resistance measured within specifications?
▶ Check for short to ground harness in control harness, short to ground in control harness.
If it is normal, go to "Component Inspection" procedure.
If it is abnormal, repair as necessary and then go to "Verification of Vehicle Repair" procedure.
▶ Check for open in signal harness.
▶ Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
C1290 Torque Sensor Main Signal-Open/Short > Inspection/Repair > Component Inspection
Component Inspection
Check torque sensor
1. Ignition "OFF".
2. Connect Scantool to Data Link Connector(DLC).
3. Engine "ON " and select "SCOPEMETER FUNCTION" on scantool.
4. operate the steering wheel to the left and right.
5. Measure output signal between terminal "2"of sensor harness connector and chassis ground.
1) Specification :
Fig.1) When turning steering wheel to right : Check whether signal voltage rises to maximum 4V based on 2.5V and main
sensor signal is the same as sub sensor signal. [Main sensor - Sub sensor] < 0.75 mA
Fig.2) When turning steering wheel to left : Check whether signal voltage descends to maximum 1V based on 2.5V and main
sensor signal is the same as sub sensor signal. [Main sensor - Sub sensor] < 0.75 mA
6. Is torque sensor main and sub signal within specifications?
▶ Substitute with a known-good EPS CM and check for proper operation.
▶ If the problem is corrected, replace EPS CM and then go to "Verification of Vehicle Repair" procedure.
▶ Check torque sensor for contamination, deterioration, or damage.
▶ Substitute with a known-good steering column assembly and check for proper operation.
Substitiuion is necessary because torque sensor is located in steering column assembly and disconnect is impossible.
▶If the problem is corrected, replace steering column assembly and then go to "Verification of Vehicle Repair" procedure.
C1290 Torque Sensor Main Signal-Open/Short > Verification of Vehicle Repair
Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scantool and select "Diagnostic Trouble Codes(DTCs)" mode.
2. Clear DTC.
3. Operate the vehicle within DTC Enable conditions in General information.
4. Are any DTCs present ?
▶ Go to the applicable troubleshooting procedure.
▶ System performing to specification at this time.
