Documentation8 min readLast updated · 1 September 2026

Troubleshooting connectivity

Most comms problems are prevented in the paddock, not solved on the pit wall. Get the kit ready before the session — and when something does go wrong, work through it in order rather than resetting the first thing you touch.

Preparation

Sort it in the paddock, not on the pit wall.

Almost everything that goes wrong mid-race was preventable beforehand. A race start is the worst possible moment to be pairing modules or hunting for a volume control — do these four before the session and most of this page never applies to you.

Pair before the race, never during it

Build the group in the paddock while you have time and the modules in your hands. Pairing under pressure, with a driver waiting, is how teams miss a start.
Charge everything to full

The LED holds solid red while charging and turns solid blue when the module is full. Anything not showing solid blue is not ready to go out.
Turn the volume up to maximum

Do it before the helmet goes on. If you are not sure where the volume is set, press volume down a few times, then press volume up repeatedly until the beep changes — that different tone is the module telling you it has reached maximum.
Confirm the link and run a mic check

Both modules should show a fading blue light — that is the connected state. Then talk to each other once, properly, before the driver leaves the pits.

LED reference

Charging LED_RED_SOLID

Fully charged LED_BLUE_SOLID

Connected LED_BLUE_PULSE

Make this a fixed routine on every race day, in the same order. The teams that never lose comms are not lucky; they are the ones who check before the session rather than during it.

Start here

The sixty-second check.

Before you reset anything, run these four. They resolve the large majority of problems, and none of them costs you your pairing.

Is there charge?

A module low on battery starts dropping the link before it dies completely. Put it on USB-C and watch for the solid red LED.
Is it actually on?

Hold the helmet + KC-PRO button for 3 seconds and confirm the LED lights and stays on. A short press does nothing.
Are they within reach of each other?

Bring both modules within a few metres and test the link there. If it works up close, your problem is range or obstruction — not pairing.
What is the LED telling you?

The LED reports the exact state the module is in. Read it before you change anything — the table below decodes every state.

Do not reset the pairing as a first move. A reset clears a working link and adds five minutes to a problem that is usually charge or distance.

Diagnostics

Read the LED before you touch anything.

Every state the module can be in shows on the LED. It is the fastest diagnostic you have, and it works with your gloves on.

LED	What it means
Solid red	Charging. The module is connected to power and has not finished.
Solid blue	Fully charged. Safe to unplug.
Solid purple	Pairing reset in progress — the existing link has just been cleared.
Alternating red / blue	Pairing mode. The module is looking for another module and will stay here until it finds one.
Pulsing blue	Linked and working. This is the state you want before the driver leaves the pits.

Status reference

Charging LED_RED_SOLID

Fully charged LED_BLUE_SOLID

Reset LED_PURPLE_SOLID

Pairing mode LED_RED_BLUE_ALT

Linked LED_BLUE_PULSE

Common faults

Eight problems, and what actually causes them.

Matched to what teams report most often. Work down the list — the causes are ordered by how frequently they turn out to be the real one.

The driver cannot hear the pit wall, or the audio is too quiet

Likely cause

The volume is not at maximum. It is by far the most common cause — at racing speed anything below maximum is usually inaudible over the engine and the wind.

Fix

Press volume down a few times, then press volume up repeatedly until you hear the beep change. That different tone means the module has reached maximum. Set it before the helmet goes on, not on the grid.

You lose the driver partway through a session

Likely cause

The link has dropped, usually because the driver went out of range or behind an obstruction on one part of the circuit.

Fix

Short-press the function button once to start a search. Time it for when the driver is coming back round towards you — a search started while they are on the far side of the circuit has far less to find.

The link drops on one part of the circuit

Likely cause

Almost always obstruction, not range. A pit building, a tunnel, a bank or a line of trailers sits between the two modules at that point of the lap.

Fix

Move the pit-wall position higher and clear of metal, with line of sight to that part of the track. Changing where you stand fixes this far more often than changing anything on the module.

The modules will not reconnect after being switched on

Likely cause

One module is not fully powered on, or the two were switched on too far apart to find each other.

Fix

Bring both within a few metres. Confirm both LEDs are lit and steady, then briefly press the small function button. Only if that fails do you need a full re-pair.

The driver hears the pit wall, but the pit wall cannot hear the driver

Likely cause

Microphone placement. The mic has moved against the chin bar, or turned away from the mouth while the helmet was being fitted.

Fix

Reposition the mic just in front of the mouth and clear of the chin bar, then run a check while the driver is still stationary. This is a mic problem, not a link problem — the link is clearly working in one direction.

Wind or engine noise drowns out the voice

Likely cause

The mic is sitting in the airflow rather than in front of the mouth, or the helmet liner has pushed the boom out of position.

Fix

Move the mic closer to the mouth and out of the direct airflow, then refit the helmet and check the position has held. The difference between good and unusable audio here is about a centimetre.

The link works, then fails an hour into a long stint

Likely cause

Battery. A module gives 6 hours of active use, and it starts dropping the link before it shuts down entirely.

Fix

Check what charge that module started the stint on. For long races, rotate to a fresh pre-paired module and run the pit-wall module permanently off USB-C so it never depletes.

A newly added module will not join the group

Likely cause

It is still linked to a previous pairing, so it never enters pairing mode.

Fix

Clear it first: hold the + and KC-PRO button for 5 seconds until the LED flashes purple, then alternates red and blue. It is now free to join. The full sequence is below.

Last resort

Clear the pairing and start again.

Only once the checks above have failed. This wipes the existing link between two modules and builds a fresh one — about two minutes, with both modules in your hands.

Power both modules on

Hold the helmet + KC-PRO button for 3 seconds on each, until the LED lights and stays on.
Clear the existing link

Hold the + and KC-PRO button for 5 seconds. The LED flashes purple briefly, then switches to alternating red and blue. The old pairing is gone.
Power both off, then on again

Same buttons as power-on: hold helmet + KC-PRO for 3 seconds to switch off, then again to switch back on.
Start pairing on both

Hold the small helmet button for a couple of seconds on the first module, then do exactly the same on the second.
Watch for the blue pulse

The LEDs alternate red and blue while they search, then settle to a pulsing blue once linked. Run a mic check before you go anywhere.

A reset clears the link on both modules. If you have more than two on the channel, resetting one means bringing the others back in as well — which is exactly why this is the last step, not the first.

A KC-PRO module being fitted to the side of a karting helmet — Both modules in your hands makes a re-pair a two-minute job.

Range

What 2 km actually means.

The published range is open-air, line of sight. What you get at a given circuit depends almost entirely on what sits between the pit wall and the kart.

Line of sight is the variable

Two kilometres in the open can become a fraction of that through a pit building. The number that matters is the one at your circuit, not the one on the box.

Metal is the worst offender

Awnings, trailers, fencing and truck bodies both reflect and absorb the signal. Getting clear of them is the single most effective fix.

Height wins

Raising the pit-wall module by a metre or two often does more than anything else you can change.

Test before it matters

Walk a module to the far side of the circuit during practice and find your weak point then — not during the race.

Worked through all of it?

Send us the LED state you are seeing and what you have already tried, and we will get you back on the channel.

Email All guides

Sort it in the paddock, not on the pit wall.

Pair before the race, never during it

Charge everything to full

Turn the volume up to maximum

Confirm the link and run a mic check

The sixty-second check.

Is there charge?

Is it actually on?

Are they within reach of each other?

What is the LED telling you?

Read the LED before you touch anything.

Eight problems, and what actually causes them.

The driver cannot hear the pit wall, or the audio is too quiet

You lose the driver partway through a session

The link drops on one part of the circuit

The modules will not reconnect after being switched on

The driver hears the pit wall, but the pit wall cannot hear the driver

Wind or engine noise drowns out the voice

The link works, then fails an hour into a long stint

A newly added module will not join the group

Clear the pairing and start again.

Power both modules on

Clear the existing link

Power both off, then on again

Start pairing on both

Watch for the blue pulse

What 2 km actually means.

Line of sight is the variable

Metal is the worst offender

Height wins

Test before it matters

Next in the manual

Worked through all of it?