What Caused the Radio to Lock?
Honda's Display Audio system uses the same anti-theft design as earlier radios: losing battery power activates a code request at next startup. Applies to both the base radio and the Display Audio unit.
- Battery replacement — the most common trigger.
- Battery disconnect during repairs — any work that interrupts battery power will activate the lock.
- Completely dead battery — a drained battery has the same result.
Worth knowing: a number of higher-trim Display Audio models from the 2014–2021 period do not use a traditional code-based lock — if the radio never showed "CODE" after a battery change, it could have a different anti-theft method tied to the vehicle VIN.
How the Code Retrieval Process Works for Honda Fit 2018
Car radios use security codes tied to the radio unit itself instead of the model or production year.
- The generator identifies your Honda radio via serial-based verification.
- After entering the serial into the form above, the system identifies the radio family and generates the code that you need.
- Simply input the digits into the Fit stereo.
- The online process is quicker and more accessible than visiting the Honda dealer.
Code Entry Process for 2018 Fit
After locating the S/N and generated the unlock code, the last step is entering it into your radio.
Honda factory radios display a locked screen when ready for input.
The process is usually simple, but button layouts and confirmation methods may vary depending on the radio version installed in your Fit.
Step-by-Step - The Correct Way to Enter It
To input the code on the 2018 Honda Fit:
- Ignition ON. Radio displays "CODE" or "ENTER CODE".
- Non-touchscreen models: Use preset buttons 1-5 to select each digit, then press and hold button 6 to confirm.
- Display Audio touchscreen: An on-screen keypad appears. Tap each digit and press "Enter" or "OK".
Lockout: 3 wrong entries activate a 60-minute lockout. Leave ignition ON. Do not cycle the key or the timer starts over.
Entering the 5-digit code on a 2018 Fit
Turn the ignition to ON so the head unit powers up and shows CODE or a numeric keypad. Honda 3rd-gen Fit codes are always 5 digits using only the numbers 1 through 6 - the keypad maps directly to preset buttons 1 through 6. If a code claimed for your 2018 Fit ever contains a 0, 7, 8, or 9 it is wrong. Press your five digits and confirm with the right-arrow / Enter control on the 5-inch LX, or the on-screen Enter control on the 7-inch Display Audio touchscreen. If the unit rejects multiple wrong codes it will lock out for roughly one hour; keep the ignition ON the whole time, because cycling power resets the timer back to a full hour.
Where to Find the Serial Number on your Fit
The initial step is to find and write down the radio's serial number.
Depending on the radio unit installed in your 2018 Fit, the serial can usually be found either through the screen menu or by checking the label on the radio itself.
Below are the most common methods to identify your S/N quickly.
2018 Honda Fit factory radios
The 2018 model year brought the mid-cycle refresh of the 3rd gen Fit, including a new Sport trim and the addition of Apple CarPlay and Android Auto to the 7-inch Display Audio:
- 5-inch color LCD audio (LX) - basic 160-watt AM/FM/CD with four speakers, hard buttons, single front USB, Bluetooth HandsFreeLink. No touchscreen and no smartphone projection on the LX.
- 7-inch Display Audio with HondaLink (Sport, EX, EX-L) - 180-watt 6-speaker system, electrostatic capacitive touchscreen, HondaLink connected services, dual USB, and now Apple CarPlay and Android Auto via the wired USB connection. The Sport trim includes the additional center-console USB Audio Interface.
The Fit was never offered with factory Honda Satellite-Linked Navigation in North America - users with the 7-inch unit relied on smartphone projection or HondaLink for routing. Both head units enforce the 5-digit Honda anti-theft code after any battery disconnect or fuse pull.
Access the S/N on the Radio Display
Try the following for your 2018 Honda Fit:
The 2018 Honda Fit may be equipped with Honda's Display Audio system (5" depending on trim) or a base non-touchscreen radio. Either type support serial number display via the 1+6 button method:
- Turn ignition to ON. Let the radio to turn on. The screen shows "CODE" if locked.
- Press and hold preset buttons 1 and 6 for approximately 3-5 seconds.
- The serial number shows in two halves (e.g.,
U3210+L0482).
Also: On 2018 Fit with the Display Audio touchscreen, look in Settings → System → Device Information – the serial may be displayed there without needing the button combination.
Manufacturer Label Inspection
If the serial number cannot be accessed via display, use the removal method.
Most Honda Fit factory radios include a label with the serial number printed on the housing.
Step-by-Step:
- Power down the vehicle.
- Remove the trim surrounding the radio.
- Unscrew the fasteners.
- Move the unit outward to access the label.
The serial number is usually located near the printed code.
If neither methods succeed on the 2018 Honda Fit:
- Turn off the vehicle.
- Detach the center stack trim panel. The 2018 Fit's modern dashboard uses plastic clips.
- On touchscreen trims: Remove the fasteners (Phillips) securing the display module.
- For standard radios: Unscrew the four screws holding the radio unit.
- Ease the unit out and locate the serial on the sticker on the unit casing.
Tip: The Display Audio unit is larger and more integrated than the base radio. Take care when extracting it.
Removing the head unit on a 2018 Honda Fit
Safety first. Disconnect the negative battery terminal and wait several minutes before working around the dash so the SRS (airbag) capacitors can discharge fully. That disconnect is what activates the radio's anti-theft lock, so only physically remove the audio unit when you have a real reason to - the on-screen 1+6 procedure pulls the serial without any disassembly.
- Open the upper dashboard storage lid to expose the factory pry notch on the edge of the radio bezel - this is the access point on every 3rd gen Fit GK.
- Insert a plastic trim tool or a tape-wrapped 3-inch putty knife into the notch and walk the bezel free. The audio unit and climate-control panel are both attached to this bezel, so support the assembly as the clips release.
- Stick to plastic panel tools - metal screwdrivers will gouge the GK Fit's matte dash plastics, which scar visibly and are awkward to refinish.
- Tip the bezel forward, then unplug the wiring harnesses for the climate controls and the head unit before lifting the bezel away.
- Three to four small chassis screws hold the audio unit to its bracket. Back them out evenly so the head unit slides straight out, then disconnect the antenna and main power/data harness at the rear.
Photograph each plug before unplugging it - the connectors look similar but only seat correctly in their original ports.
Example: Honda Fit serial number label location
S/N Patterns and Prefixes
Depending on which radio fitted to the 2018 Honda Fit:
U1234L5678– Standard Honda OEM formatHBM####– Used in Display Audio and navigation units913A####– Some Alpine-manufactured units
The 2018 Fit may have: base CD radio (U/L format), Display Audio 5"/7" (HBM format), or navigation unit (HBM format). All use a 5-digit unlock code.
Important Verify you copy the serial number, not the part number (which starts with 39100, 39101, or similar Honda part coding).
2018 Fit radio serial format
Honda 3rd-gen Fit head units show an 8-character alphanumeric serial - mixed letters and digits with no dashes, spaces, or punctuation. On the 5-inch LX the value typically alternates between two screens prefixed with U (first 4 characters) and L (last 4 characters); ignore the prefix labels and copy down the eight characters between them. On the 7-inch Display Audio the serial usually appears as a single 8-character string on the touchscreen. Read the value carefully and watch for the classic look-alikes: 0 versus O, 1 versus I, 5 versus S, and 8 versus B. A single mistyped character returns the wrong code from any retrieval source.
Fixing Common Code Entry Problems for 2018 Fit
On the Display Audio, a rejected code usually points to the serial was incorrectly noted. Either retrieval method can produce the correct serial — verify that the serial you submitted was read off the radio unit and not from an online database.
After one failed entry, stop and reach out before trying again — a second wrong attempt brings you closer to the 60-minute lockout. A no-charge serial reverification can be done on request.
Code entry depends on the specific radio in the 2014–2021 Fit:
- Non-touchscreen base radio: Use preset buttons 1–5 to cycle to each digit, then hold button 6 to confirm — identical to older Honda platforms.
- Display Audio 5" or 7" touchscreen: An on-screen numeric keypad appears when the code prompt is active. Tap each digit and press OK or Enter on screen.
If the touchscreen is unresponsive, try the physical preset buttons — some units accept both input method. Ensure the screen is fully booted before attempting entry.
If the Display Audio screen powers on but shows the home screen without a "CODE" display, check the following:
- Anti-theft may not have triggered — some battery changes don't trigger the lock if power was restored fast.
- Certain Display Audio units, the code prompt appears only on the audio portion of the screen, not the navigation display — give it a moment after startup.
- Check the Settings → System → Device Information route; should the serial appear, the unit could still be functional without a code.
If none of these apply, a fuse check is the next step — a failed fuse will stop the radio from showing any display at all.
The Display Audio era spans radios using different serial formats depending on the trim level:
U####L####— base CD radio serial (10 characters, two halves).HBM####— Display Audio 5"/7" and navigation modules.913A####— some Alpine OEM configurations.
Part numbers printed nearby start with 39100 or 39101 — these are not serials. If uncertain, use the Settings → Device Information menu or the 1+6 button method to display the serial directly from the unit.
The Display Audio platform uses the same three-try lockout as earlier Honda radios. To recover:
- Maintain the ignition in ON or ACC — do not switch off.
- Wait out the full 60-minute period. The touchscreen may go to sleep during this time — this is expected.
- After 60 minutes, the radio re-displays "CODE" and you can.
On Display Audio touchscreen models, the lockout countdown operates even when the screen is off. Simply leave the vehicle running or the ignition on ACC for the full hour.