Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Signal description, Control unit for the steering wheel angle sensor (SAS)
The values in the chart represent the values between the connections shown in column 1 and #A40 (ground), unless otherwise stated in brackets.
It is important that the test box is connected and the ground points checked before testing begins.
| U= | DC voltage (V) | Ubat = | battery voltage (V) | |
| I = | amperage (A) | Ulow = | voltage close to 0 V |
| Test box connection | Control unit connection | Signal type | Ignition on | Other |
| #A25 | #1 | 15 supply (voltage supply from the ignition lock) | U(Ubat | - |
| #A26 | #2 | Voltage supply to steering wheel angle sensor | U(Ubat | 15 supply through control unit |
| #A27 | #3 | Steering wheel angle signal A | <0.25 V (low) >0.75 V (high) I(1 mA |
Steering wheel angle signal The coding wheel in the steering wheel angle sensor is perforated with a special code template. Two circuits, each with 4 LEDs and 4 receptors, read the coding wheel and send a pulsed signal containing information about the position of the steering wheel. |
| #A28 | #4 | Steering wheel angle signal B | <0.25 V (low) >0.75 V (high) I(1 mA |
Steering wheel angle sensor signal For more information, see steering wheel angle signal A. |
| #A29 | #5 | Steering wheel position signal R1 | <0.25 V (low) >0.75 V (high) I(1 mA |
Sector identifier For more information, see steering wheel angle signal A. |
| #A30 | #6 | Control unit communication wire (CAN H) | U=2-3 V | CAN High speed, Multiplex wire. |
| #A31 | #7 | Signal and power ground for steering wheel angle sensor | - | - |
| #A32 | #8 | LED circuit 2 signal | - | LED circuit 2 current test |
| #A33 | #9 | LED circuit 1 signal | - | LED circuit 1 current test |
| #A34 | #10 | Steering wheel angle signal IX | <0.25 V (low) >0.75 V (high) I(1 mA |
Steering wheel angle sensor signal For more information, see steering wheel angle signal A. |
| #A35 | #11 | Steering wheel angle signal IY | <0.25V (low) >0.75 V (high) I(1 mA |
Steering wheel angle sensor signal For more information, see steering wheel angle signal A. |
| #A36 | #12 | Steering wheel position R2 signal | <0.25 V (low) >0.75 V (high) I(1 mA |
Sector identifier For more information, see signal A. |
| #A37 | #13 | Steering wheel position R3 signal | <0.25 V (low) >0.75 V (high) I(1 mA |
Sector identifier For more information, see signal A. |
| #A38 | #14 | Steering wheel position R4 signal | <0.25 V (low) >0.75 V (high) I(1 mA |
Sector identifier For more information, see signal A. |
| #A39 | #15 | Control unit communication wire (CAN L) | U=2-3 V | CAN Low speed, Multiplex wire. |
| #A40 | #16 | Signal and power ground (measured against the battery negative terminal). | U(Ulow | - |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.