Bosch Motorsport M5 ABS Integration Kit for Toyota GR Yaris (Gen 1)
This is a highly integrated Bosch Motorsport M5 ABS system designed to replace the factory ABS in the Gen 1 Toyota GR Yaris.
At the heart of the package is the Bosch Motorsport M5 ABS, a professional-level motorsport unit used in racing worldwide. The M5 provides ultra-fast processing, highly accurate wheel slip control, and configurable ABS strategies for track use. Multiple driver-selectable maps allow the ABS behaviour to be tuned for tyres, surface conditions, and driving style.
The GR Yaris earns its reputation on circuit, but its factory braking calibration is built around road-car stability compliance, not race pace. This kit replaces it with fully adjustable motorsport slip control while keeping the installation clean and factory-looking in the cabin.
The problem with factory ABS in competition: what track drivers call “ice mode”
ABS works by holding each tyre near a target slip ratio, the difference between wheel speed and vehicle speed, where 0% is a freely rolling tyre and 100% is a locked one. Peak braking force sits somewhere between the two, and exactly where depends on the tyre and the surface. The cycling you feel through the pedal is the system chasing its target, and while it’s in slip control, pressing harder adds nothing; extra pedal force won’t be sent to a tyre the system already considers at its limit.
Road-car calibrations have to be built conservatively: one calibration must stay safe on every surface a road car can meet, down to the very worst. Under genuine circuit braking (real speed, semis or slicks, kerbs and bumps working the tyre) that conservative logic can settle on a slip target far below the grip actually available. The result is what drivers call ice mode: the system refuses to build brake pressure no matter how hard you stand on the pedal, and the only way out is to come almost completely off the brake, let the wheels match the car’s speed, and reapply. If you braked at the limit for the corner, that margin doesn’t exist.
It isn’t a fault, and pads, fluid or bigger discs won’t touch it. It’s a road calibration operating outside the envelope it was designed for.
Motorsport ABS approaches the problem from the other direction: the driver selects the calibration for the tyre and conditions actually in use, and the system controls to a slip target appropriate for genuine circuit grip. Eleven selectable calibrations on the 12-position map switch cover the range from wet circuit to slicks, chosen before the braking zone, not discovered during it.
Brake balance: what the factory system quietly manages for you
On many modern platforms the ABS/ESP doesn’t just prevent lock-ups; it actively manages front-to-rear brake distribution. Under light braking the system can run more rear brake than the hydraulics alone would give, keeping the car flat; under hard braking it bleeds rear pressure down as weight transfers forward. The distribution your car actually runs is electronic, not mechanical.
That has two consequences for a competition build. Unplugging the ABS on a modern car doesn’t return it to some honest pre-electronic state; it removes the brakeforce distribution the base hardware was designed around, and can leave the car with a hard pedal and a rear balance never intended to stand on its own. And altering mechanical bias underneath a stock system means fighting a computer that’s redistributing pressure on top of your changes.
A motorsport ABS conversion makes brake balance deliberate again: the overall front-to-rear balance is set properly in hardware, which is why this kit includes a bias valve installation option, and the M5 then controls slip at each wheel from that correct baseline.
What’s Included
- Bosch Motorsport M5 ABS unit, with mounting in the factory ABS location, no drilling required
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Factory hard lines to the wheels are retained: only the master-cylinder pipes need to be made at install
- Factory wheel speed sensors retained; mating connectors and terminals for the factory Toyota WSS harnesses supplied, terminated by the installer to suit harness routing for the vehicle’s configuration
- Optional bias valve installation for the centre console, with mountings and 3D-printed drill templates for the bulkhead pass-throughs and console trim
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ABS map switch mounted in the original auxiliary socket beside the drive mode selector; both apertures are the same size, so the console keeps its factory symmetry
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MIL and main switch located between the map switch and the drive mode selector
- Mounting hardware throughout
Brake lines from the master cylinder to the hydraulic unit are made to suit the vehicle at install: 909 specifications call for Goodridge or Speedflow hardware.
Key Benefits
- Factory ABS location, factory wheel lines, factory sensors, the hydraulic and sensing installation is largely bolt-in; only the master-cylinder pipes are made at install
- Factory-symmetric cabin: the map switch fills the original auxiliary socket beside the drive mode selector, with the MIL and main switch between them
- Console bias valve option with printed drill templates takes the guesswork out of the one modification the interior needs
- Multiple driver-selectable ABS calibrations for slicks, semi-slicks and wet circuit work
- Proven Bosch Motorsport reliability
ECU and dash integration
Integration with the factory Toyota ECU and electronics is not supported. Customer cars to date run MoTeC or Syvecs engine management and displays, and the 909 kit integrates with those systems for warnings and data. The factory cluster lamps remain, though in most builds the factory cluster sits behind a motorsport display; these are circuit cars. A stock-ECU integration may be developed in the future; contact us to register interest.
Technical Specifications: Bosch Motorsport M5 ABS
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Control strategy: High-speed multi-channel wheel slip control
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Maps: Multi-map system with driver-selectable modes
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Inputs: 4× wheel speed sensors
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Outputs: Hydraulic modulation via Bosch Motorsport valve block
Bosch Motorsport M5 vs Factory ABS
|
Factory GR Yaris ABS/ESC |
Bosch Motorsport M5 ABS Kit |
| Technology |
Road-car ABS/ESC calibration |
Modern, high-speed multi-channel motorsport ABS |
| ABS maps |
Single road calibration |
Eleven selectable calibrations for different tyres and conditions |
| Stability/ESC behaviour |
Road-biased stability intervention |
Factory ESC functions replaced by motorsport slip control (see ECU and dash integration) |
| Wheel speed sensors |
Factory sensors |
Factory sensors retained, with mating connectors and terminals supplied |
| Driver control |
None |
ABS map switch in the original auxiliary socket beside the drive mode selector |
| Installation |
Factory fit |
Factory ABS location, no drilling; factory wheel lines retained; master-cylinder pipes made at install |
| Brake bias |
Electronically managed by ABS/ESC |
Set deliberately in hardware, with optional console bias valve installation |
| Performance |
Adequate for road use; limited under hard braking on track |
Motorsport-level braking performance for the circuit |
| Adjustability |
None |
Adjustable for tyres, surface conditions, and driver preference |
FAQs
Q: Is the Bosch Motorsport M5 ABS included in this kit, or is it separate?
A: The kit includes the Bosch Motorsport M5 ABS unit, fully integrated with mounting, sensor connectors and cabin hardware.
Q: Will installation require cutting or permanent modifications?
A: No drilling is required, the M5 mounts in the factory ABS location and the factory wheel lines and sensors are retained. The only interior modification is the optional console bias valve, and the kit supplies 3D-printed drill templates for exactly that job.
Q: Do I need special tools or skills to install the kit?
A: Some expertise is required. The master-cylinder pipes are made to suit at install, and the supplied Toyota WSS mating connectors are terminated by the installer to suit the harness routing for the vehicle’s configuration. Professional installation is recommended. We cover the whole job, brackets to commissioning, in what a Bosch Motorsport ABS M5 install actually involves.
Q: Does this affect the GR-Four drivetrain?
A: The kit replaces braking control only; drivetrain hardware is untouched. Vehicle-level integration on customer cars to date is handled by the MoTeC or Syvecs platforms they run.
Q: Can I run it with the standard ECU?
A: Integration with the factory Toyota ECU is not currently supported, see the ECU and dash integration section. A stock-ECU pathway may be developed in the future; contact us to register interest.
Q: My factory ABS has never caused a problem. Why replace it?
A: The limitation shows up at circuit pace under maximum braking, precisely when you can’t afford it. See the ice mode section above.
Q: Why not just unplug the ABS instead?
A: On modern platforms that also deletes the electronic brake distribution the car was designed around. A motorsport system with properly set mechanical balance is the engineered path, not the workaround.
Q: Can I adjust the ABS behaviour?
A: Yes. Eleven selectable calibrations on the 12-position map switch allow the ABS response to be tuned for the tyre and conditions in use.
Q: Is the system validated for road use?
A: No, Bosch Motorsport ABS is for track usage only.
Q: Will this kit suit a LHD car?
A: We have not had access to a LHD vehicle for testing. For the right pilot customer we would be willing to work together on testing, please get in touch via the contact page.
Q: What's the difference between the Clubsport, Kit 1 and Kit 2 core options?
A: Every option includes the same M5 system and the same 909 platform hardware. The Clubsport core uses Bosch's universal harness, the right choice for most club and time-attack builds. Kit 1 moves to a vehicle-specific loom and supports the M5's advanced control functions for cars with real aero or braking beyond about −2 g, and Kit 2 adds Autosport-specification connectors at the wheel-speed sensor leads for endurance-style service schedules. Our kit comparison guide covers the choice in detail.
