Speed Limiter Installation: What to Expect on Fitting Day

Speed limiter installation typically takes two to three hours per vehicle, is carried out at your premises by a mobile engineer, and includes full calibration and certification on the day. No overnight stays in a workshop are required. The vehicle arrives in the morning and is back in service by lunchtime, fully compliant and ready to operate.

If you have never had speed limiters fitted before, or are rolling out a fleet-wide installation programme, understanding exactly what happens during the fitting process helps you plan effectively and minimise disruption to operations.

Before the Engineer Arrives

Vehicle Assessment

Before installation day, AutoKontrol conducts a vehicle assessment. This can be done remotely for common vehicle types — we maintain a database covering thousands of makes, models, and engine variants — or may require a brief physical inspection for unusual or older vehicles.

The assessment determines:

• Interface method. How the speed limiter will connect to the vehicle’s throttle system. Modern vehicles with electronic throttle control (drive-by-wire) use a direct electronic interface. Older vehicles with cable-operated throttles require a mechanical actuator.
• Mounting location. Where the speed limiter module will be installed within the engine bay or cab.
• Wiring route. The path for connecting the limiter to the vehicle’s electrical system, speed signal, and throttle interface.
• Parts required. The specific limiter model and any vehicle-specific adapters, brackets, or harnesses needed.

This assessment ensures the engineer arrives on fitting day with everything required. There should be no surprises and no return visits.

Preparing Your Vehicles

On the day, you need to provide:

• The vehicle, parked in a location with enough space for the engineer to work around it with bonnet and cab open
• Vehicle keys, so the engineer can start and test the vehicle
• Access to the vehicle’s documentation — V5C or fleet records confirming the vehicle registration, VIN, and current mileage

If you are having multiple vehicles fitted, stagger them so that one vehicle is being fitted while the previous one is being road-tested. This keeps the programme moving efficiently.

The Installation Process: Step by Step

Step 1: Pre-Installation Inspection (15 Minutes)

The engineer begins with a physical inspection of the vehicle. This confirms the assessment findings, checks for any recent modifications that might affect the installation, and verifies the vehicle is safe to work on.

The engineer also checks the existing speed signal. On most modern vehicles, this is taken from the vehicle’s CAN bus network or from the ABS wheel speed sensor. On older vehicles, a dedicated speed sensor may need to be fitted to the gearbox or transmission.

Step 2: Module Installation (45-60 Minutes)

The speed limiter module — in AutoKontrol’s case, the System 80 unit — is mounted in a secure location within the engine bay or behind the dashboard. The location is chosen for protection from heat, vibration, and water ingress, while remaining accessible for future maintenance.

The module is connected to:

• The vehicle’s power supply — with fused, dedicated connections to ensure reliable operation
• The speed signal — providing the vehicle speed data the limiter needs to determine when to activate
• The throttle interface — on drive-by-wire vehicles, this is an electronic connection that allows the limiter to modulate the throttle signal. On cable-throttle vehicles, a mechanical actuator is fitted to the throttle cable.

All wiring is routed, secured, and protected to OEM standards. Cable ties, grommets, and conduit are used to ensure the installation will survive the vehicle’s working life without chafing or failure.

Step 3: Tamper-Proofing (10 Minutes)

Once the installation is physically complete, tamper-evident seals are fitted to the speed limiter module and all adjustment or connection points. These seals are a legal requirement for HGVs and PSVs and are expected by DVSA at inspection.

The seals are unique to the fitting centre and are recorded on the calibration certificate. If a seal is later found broken, it indicates potential tampering and triggers a mandatory recalibration.

Step 4: Calibration (30-45 Minutes)

Calibration is the process of setting and verifying the exact speed at which the limiter activates. For a detailed explanation of calibration methods, see our guide to speed limiter calibration.

For HGVs, the legal maximum is 56 mph (90 km/h). For buses and coaches, it is 62 mph (100 km/h). For voluntary installations on vans or other vehicles, the speed is set to whatever the fleet operator specifies.

Calibration is verified either by driving the vehicle on a suitable road and comparing the limiter activation point against GPS speed, or by using a rolling road. The engineer makes any necessary adjustments until the limiter activates within the required tolerance — typically plus or minus 2 mph.

Step 5: Road Test (15-20 Minutes)

The engineer takes the vehicle for a road test to verify:

• The speed limiter activates smoothly at the set speed
• The throttle response below the set speed is normal and unaffected
• There are no warning lights, fault codes, or abnormal behaviour
• The speed limiter deactivates correctly (for systems with a deactivation feature, such as emergency override)

The road test also verifies that the installation does not affect any other vehicle system — cruise control, traction control, engine management, or emissions systems.

Step 6: Documentation and Handover (15 Minutes)

On completion, the engineer provides:

• A calibration certificate — confirming the set speed, calibration method, date, and next calibration due date
• A speed limiter plate — the metal plate fitted to the vehicle (required on HGVs and PSVs) showing the set speed and fitting centre details
• An installation record — detailing the work carried out, parts fitted, and vehicle details

The engineer also briefs the driver or fleet manager on what to expect — how the limiter feels in normal driving, what the warning indicators mean, and what to do if a fault is suspected.

Multi-Vehicle Programmes

For fleet-wide installations, AutoKontrol operates a mobile fitting service that comes to your premises. A single engineer can typically fit three to four vehicles per day, depending on complexity. For larger programmes, multiple engineers can work simultaneously.

We coordinate with your fleet operations team to schedule fittings around vehicle availability, minimising the impact on your daily operations. Vehicles are typically out of service for no more than three hours each.

What Does It Cost?

Speed limiter installation costs vary by vehicle type, interface method, and whether you are fitting a basic speed limiter or the full TrackSpeed system with GPS tracking and GeoKontrol capability. For a detailed breakdown, see our speed limiter cost and pricing guide.

As a general indication, a standard System 80 installation on a common vehicle type typically costs between £400 and £700 including the unit, fitting, calibration, and certification.

Book Your Installation

Whether you need a single vehicle fitted for compliance or a fleet-wide installation programme, AutoKontrol’s engineering team can plan and deliver it with minimal disruption to your operations. Request a free quote to get started.