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.
Control Module And Abs Hydraulic Modulator
The brake control module (BCM) is mounted on the hydraulic modulator in the engine compartment.
The control module is supplied with power via two fuses and connected to ground by two ground terminals.
There are diagnostics for the valve coils and the pump motor. There are three different versions of the brake control module (BCM).
ABS control module
The control module contains two different micro-processors which receive signals from different sensors in the system. The micro-processors operate in parallel and use a program to compute the necessary ABS and electronic brake force distribution functions. The ABS control module has eight valve coils for the hydraulic valves, four outlet valves and four inlet valves.
The control module has a connector for connection to the cable harness in the car.
Control module for STC and TRACS AWD
The control module for STC/TRACS AWD has twelve valve coils for the hydraulic valves. Otherwise its contents are the same as the control module for ABS. The four additional valve coils are used for stability and traction control.
Control module for DSTC
The control module for DSTC looks the same as an STC control module. However the software is different and it is connected to the brake pressure sensor.
When replacing a DSTC control module, the control module must be calibrated using VIDA (Volvo scan tool).
ABS hydraulic modulator
There are four versions of the ABS hydraulic modulator:
- ABS
- STC
- DSTC
- TRACS AWD.
The ABS hydraulic modulator is located against the cowl panel in the engine compartment. The ABS hydraulic modulator consists of:
- hydraulic valves
- relief valves
- an integrated brake pressure sensor
- a pump motor.
The pump motor generates the brake pressure required during stability and traction control.
There are diagnostics for the hydraulic valves, brake pressure sensor and the pump motor.
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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.