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.
2012 Volvo XC90 R-Design, AWDFACTORY OEM SERVICE PROCEDURE
Signal Specification, Brake Control Module (BCM) With STC/ TRACS
All values given are between the relevant terminal in column 1 and terminal #A16 or #A47 (ground), unless otherwise indicated in brackets.
Pins 6, 9, 13, 17-31, 35, 38-41 and 44 are not used.
NOTE:
It is important that the breakout box is connected and that the ground connections have been checked before starting to measure.
| U= | DC voltage in volts (V) | Ubat = | battery voltage (V) | ||
| I = | current in amperes (A) | Ulow = | voltage approximately 0 V | ||
| F = | Frequency in Hertz (Hz) |
| Breakout box terminal | Terminal ECU | Signal type | Ignition on | Miscellaneous |
| #A1 | #1 | Pump motor, 30-supply (power supply from the battery) | U = Ubat | With a 30 A fuse. |
| #A2 | #2 | Diagnostic lead C-link | - | - |
| #A3 | #3 | Pedal position sensor, signal | 0-5 V | Analogue signal which indicates the position of the brake pedal. 0 mm: ≈0V 38 mm: ≈ 95% of 5 V |
| #A4 | #4 | 15-supply (power supply from the ignition switch) | U = Ubat | - |
| #A5 | #5 | Pedal position sensor, signal ground | U = Ulow | - |
| #A6 | #6 | - | - | - |
| #A7 | #7 | Pedal position sensor, power supply | U =5 V | The pedal position sensor receives 5 V from the control module. |
| #A8 | #8 | Wheel sensor right rear, signal output | Tooth against sensor U≈Ulow Cover against sensor U≈Ubat |
Measure by creating a temporary voltage supply between #1 via a 1kΩ and #8. Connect a voltmeter between #8 and ground connection #16. Turn the wheel slowly. |
| #A9 | #9 | - | - | - |
| #A10 | #10 | Wheel sensor left rear, signal output | Tooth against sensor U≈Ulow Cover against sensor U≈Ubat |
Measure by creating a temporary voltage supply between #1 via a 1kΩ and #10. Connect a voltmeter between #10 and ground connection #16. Turn the wheel slowly. |
| #A11 | #11 | Control modules communication cable (CAN H) | U=2-3 V | - |
| #A12 | #12 | Wheel sensor right front, signal output | Tooth against sensor U≈Ulow Cover against sensor U≈Ubat |
Measure by creating a temporary voltage supply between #1 via a 1kΩ and #12. Connect a voltmeter between #12 and ground connection #16. Turn the wheel slowly. |
| #A13 | #13 | - | - | - |
| #A14 | #14 | Wheel sensor left front, signal output | Tooth against sensor U≈Ulow Cover against sensor U≈Ubat |
Measure by creating a temporary voltage supply between #1 via a 1kΩ and #14. Connect a voltmeter between #14 and ground connection #16. Turn the wheel slowly. |
| #A15 | #15 | Control modules communication cable (CAN L) | U=2-3 V | - |
| #A16 | #16 | Power and signal ground | U = Ulow | Ground terminal for the input and outlet valves and signal to the control module. |
| #A17 | #17 | - | - | - |
| #A18 | #18 | - | - | - |
| #A19 | #19 | - | - | - |
| #A20 | #20 | - | - | - |
| #A21 | #21 | - | - | - |
| #A22 | #22 | - | - | - |
| #A23 | #23 | - | - | - |
| #A24 | #24 | - | - | - |
| #A25 | #25 | - | - | - |
| #A26 | #26 | - | - | - |
| #A27 | #27 | - | - | - |
| #A28 | #28 | - | - |
- |
| #A29 | #29 | - | - | - |
| #A30 | #30 | - | - | - |
| #A31 | #31 | - | - | - |
| #A32 | #32 | 30-supply to the valves (power supply from the battery) | U = Ubat | With a 30 A fuse. |
| #A33 | #33 | Front right wheel sensor. signal | Tooth against sensor: I≈14 mA Cover against sensor: I ≈ 7 mA |
The sensor generates a pulsed signal (quadratic wave) with a fixed pulse ratio when the pulse wheel rotates. The frequency increases with speed. For test of sensor's function, see #12 in table. |
| #A34 | #34 | Front right wheel sensor, power supply | U = Ubat | The wheel sensor receives 12 V from the control module. |
| #A35 | #35 | - | - | - |
| #A36 | #36 | Rear left wheel sensor, power supply | U = Ubat | The wheel sensor receives 12 V from the control module. |
| #A37 | #37 | Rear left wheel sensor, signal | Tooth against sensor: I≈14 mA Cover against sensor: I ≈ 7 mA |
The sensor generates a pulsed signal (quadratic wave) with a fixed pulse ratio when the pulse wheel rotates. The frequency increases with speed. For test of sensor's function, see #10 in table. |
| #A38 | #38 | - | - | - |
| #A39 | #39 | - | - | - |
| #A40 | #40 | - | - | - |
| #A41 | #41 | - | - | - |
| #A42 | #42 | Rear right wheel sensor, signal | Tooth against sensor: I≈14 mA Cover against sensor: I ≈ 7 mA |
The sensor generates a pulsed signal (quadratic wave) with a fixed pulse ratio when the pulse wheel rotates. The frequency increases with speed. For test of sensor's function, see #8 in table. |
| #A43 | #43 | Right rear wheel sensor, power supply. | U = Ubat | The wheel sensor receives 12 V from the control module. |
| #A44 | #44 | - | - | - |
| #A45 | #45 | Front left wheel sensor, power supply | U = Ubat | The wheel sensor receives 12 V from the control module. |
| #A46 | #46 | Front left wheel sensor, signal | Tooth against sensor: I≈14 mA Cover against sensor: I ≈ 7 mA |
The sensor generates a pulsed signal (quadratic wave) with a fixed pulse ratio when the pulse wheel rotates. The frequency increases with speed. For test of sensor's function, see #14 in table. |
| #A47 | #47 | Power and signal ground | U = Ulow | Ground terminal for the pump motor. |
Factory Service Tools
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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.