Where to Find the Serial Number on your 300C
The useful fact to know is that factory radios use a specific serial number to identify each unitindividually.
The security system links the code directly to this serial.
Different from vehicle-specific data such as VIN or registration information, it is not determined by the model or production year, so you'll be able to get it even if you have an aftermarket radio.
Depending on the maker and radio installed in your Chrysler 300C, the access method is different.
These are the most reliable ways to find it.
2018 Chrysler 300C - Which Head Unit Is Fitted?
The 2018 Chrysler 300C is the top trim of the LD-platform 300 line-up and ships exclusively with the Uconnect 4 family. Because 300C is the flagship trim, the 8.4-inch UAQ NAV is the standard radio - but a UAS swap or repair-shop replacement could also leave a UAS or UAG unit in the dash.
- Uconnect 4C NAV (sales code
UAQ) - 8.4-inch touchscreen with built-in GPS. Standard equipment on the 2018 300C. Visual ID: large 8.4-inch screen filling the dash bezel opening edge to edge, with a dedicated NAV/Map tile on the home screen and on-board maps that work without a phone. Apple CarPlay and Android Auto are also supported. - Uconnect 4C (sales code
UAS) - 8.4-inch non-NAV touchscreen. Not factory-fitted to 300C, but may appear after a service replacement. Same 8.4-inch glass as UAQ but with no Map/NAV tile and no on-board maps. - Uconnect 4 (sales code
UAG) - 7-inch non-NAV touchscreen. Standard on entry 300 trims rather than 300C, but mentioned here in case a smaller screen has been retrofitted to a 2018 300C.
Quick check: 8.4-inch screen with a Map/NAV tile = UAQ (factory fit on 300C). 8.4-inch with no Map tile = UAS. Smaller 7-inch screen = UAG.
View Your Serial Number via the Radio Display
Try the following for your 2018 Chrysler 300C:
The 2018 Chrysler 300C — Chrysler's HEMI V8 flagship sedan — features the Uconnect 8.4" Classic (RA3). The 300C's luxury-spec cabin features the same climate control cluster below the 8.4" screen used to trigger Dealer Mode.
Hold Climate Up, Climate Down, and Front Defrost simultaneously for 5 seconds (ignition in ACC or ON). Dealer Mode opens on the display. Go to: System Info → Radio Part Info → Serial Number.
Read the Serial Straight from the Touchscreen
The 2018 Chrysler 300C ships with Uconnect 4C 8.4-inch hardware - typically the UAQ NAV unit on this trim. The radio serial number can usually be read straight from the touchscreen via the hidden dealer/diagnostic menu, with no need to pull the unit out of the dash.
Uconnect 4C 8.4 (UAQ - factory standard on 300C)
Switch the ignition to RUN/ACC and wait for the Uconnect interface to finish booting. Press and hold the driver-side temperature UP, the driver-side temperature DOWN, and the front DEFROST buttons together for roughly 5-10 seconds until the dealer/engineering screen opens. If the climate-button shortcut does nothing, press and hold the bottom-left and bottom-right corners of the screen at the same time for about 5-10 seconds. Once inside, browse to the radio/system info section to read the 14-character serial number printed on screen, then photograph the screen so each character can be transcribed without typos.
If a UAG 7-inch is fitted instead
Place the ignition in RUN/ACC and let the screen finish loading. Press and hold both temperature UP and temperature DOWN buttons together for around 5-10 seconds to enter the engineering menu, then browse to System Info / Target Main Data to view the serial. Photograph the display before transcribing the digits.
300C's Hardware Label Method
If the serial number cannot be accessed on-screen, use the pull-out method.
Most Chrysler 300C OEM radios include a label with the serial number printed on the casing.
Steps:
- Switch off the vehicle.
- Lift the bezel surrounding the radio.
- Release the fasteners.
- Slide the unit outward to access the label.
The serial number is usually located near the printed code.
If Dealer Mode is unavailable on the 2018 Chrysler 300C, the RA3 unit needs to come out from the 300C's premium center stack. The 300C's premium bezel may need more careful handling when removing the trim bezel.
- Gently pry off the trim panel with a plastic trim tool — use care with the premium trim.
- Remove the 4 Torx T20 mounting screws.
- Slide the unit out to read the serial label on the side or back of the radio chassis.
Pulling the Head Unit to Read the Chassis Sticker
If the on-screen menu is unavailable on the 2018 Chrysler 300C, the chassis label on the radio itself remains a reliable source for the serial number. The Uconnect 4C 8.4 unit on the LD-platform 300C is closely tied to the climate cluster, so work slowly to avoid breaking trim clips.
Safety first. Turn the ignition off, take out the key, disconnect the negative battery terminal, and wait several minutes before touching wiring. Never disturb the yellow airbag/SRS connectors and use plastic trim tools so nothing shorts or breaks.
Tools you will need. Plastic trim removal kit (a Mopar C-4755 trim stick or equivalent), Phillips and small Torx bit set, 7mm/10mm socket set, flashlight.
Removal overview. Disconnect and isolate the negative battery cable per the Mopar service manual procedure. Pop the centre instrument panel bezel out from the bottom edge with a plastic pry tool, work up the sides, and unclip the A/C-heater control and clock connectors before setting the bezel aside. Remove the mounting fasteners (typically four screws, two top and two bottom) holding the radio cage to the dash support, slide the head unit straight rearward, and disconnect the antenna lead and the multi-pin power/data harness on the back.
Where the serial sits. The serial number is printed on a barcode/sticker label on the top or side of the radio housing, alongside the part number and supplier markings.
Tips. If the bezel resists, stop and double-check for hidden fasteners under trim or knee bolster panels rather than pulling harder. If you are not comfortable working around the airbag wiring or the integrated climate cluster, have a professional installer remove the unit for you.
Example: Chrysler 300C serial number label location
What a Valid Serial Number Looks Like
The 2018 Chrysler 300C HEMI RA3 radio serial formats:
T00AM– Harman VP2 RA3 — typical on the 300C premium trimsT00BE– Continental variant of the 8.4" systemTM9– Earlier Harman production
Serial is 14 alphanumeric characters. Part number on the same label starts with P05064 or 68 — skip it.
Typical Serial Number Formats for 2018 Chrysler 300C Radios
The factory radio on the 2018 Chrysler 300C is the Uconnect 4C 8.4 NAV (UAQ). It uses the standard Mopar/Uconnect head-unit serial style, with the exact prefix depending on which supplier (Visteon, Continental, Harman or Panasonic) built that particular unit.
Uconnect 4C 8.4 (UAQ)
Typically a 14-character alphanumeric string printed on the chassis label. Commonly begins with T - frequent prefixes include T00AM, TM9 and TQ1 - or with A2C on Continental-built variants. The serial usually runs as a continuous string of letters and digits with no dashes or spaces.
If a UAS or UAG has been swapped in
The 8.4-inch UAS uses the same prefix family as UAQ. The 7-inch UAG usually carries a Mopar/Harman or Panasonic-style serial on the chassis sticker; the printed label on the unit itself is the authoritative reference. Always copy the serial exactly as printed and avoid guessing characters that look unclear.
How Code Entry Works on Your Chrysler Radio
Now that you've found the serial number and retrieved the unlock code, the final part is entering it into your radio.
Chrysler original head units display a locked screen when ready for input.
The process is simple, but button layouts and confirmation methods may change depending on the radio version installed in your 300C.
Entering Process Explained
Entering the unlock code the 2018 Chrysler 300C's Uconnect 8.4":
- Turn ignition to ON. The screen shows "ENTER CODE".
- Use the on-screen keypad to enter your 4-digit code.
- Radio auto-confirms after the 4th digit.
3 wrong attempts cause a 60-minute lockout. Keep ignition ON for the full duration without switching off.
Step-by-Step Code Input Guide
Once the unlock code has been retrieved, the 2018 Chrysler 300C Uconnect head unit can be unlocked at the dash without a scan tool or dealer visit.
Limited attempts. Mopar/Uconnect head units only accept three incorrect tries before the radio enters a WAIT state, so confirm every digit before pressing it.
Entering the code. Place the ignition in RUN/ACC so the radio powers up but the engine stays off. Wait for the display to show CODE, Please enter Anti-Theft Code, or a similar prompt. On the Uconnect 4C 8.4 (UAQ/UAS), tap the on-screen number pad to enter each digit and confirm with the on-screen OK/Enter button. If a UAG 7-inch unit is fitted, press the numbered preset buttons in sequence (preset 1 for the first digit, preset 2 for the second, and so on) - or use the on-screen keypad if the unit prompts for it.
If a wrong code was entered. If WAIT appears after wrong attempts, leave the radio powered with the ignition in RUN for a continuous 30 minutes (the vehicle may be driven during this time) before trying the correct code again.
Unlock Your 2018 Chrysler 300C Radio in Minutes - How It Works
Car radios use security codes tied to the radio unit itself instead of the model or production year.
- The system uses the 300C's radio serial to retrieve the unlock code.
- Once the serial number is submitted, the system identifies the radio unit and retrieves the corresponding code.
- You can then enter the code directly into your Chrysler radio.
- Compared to Chrysler dealer retrieval, this method is faster and more convenient.
Why Is the Radio Asking for a Code?
The 2018 Chrysler 300C RA3 locks automatically after any power disconnection. Even the premium 300C trim uses the same security system — a disconnected radio is useless without the code.
Most common cause: battery replacement or disconnect. Other causes:
- Failed fuse after electrical work
- Buying the 300C used without a known code
- Battery disconnect during service
- Battery drained from storage
Code comes from the radio serial number — not the VIN.
Fixing Common Code Entry Problems for 2018 300C
On the 300C label: serial = 14 alphanumeric chars, starts with T00AM, T00BE, or TM9. Part number starts with P05064 or 68 — not the serial.
The 300C Uconnect RA3 uses touchscreen-only code entry. Tap each digit on the on-screen keypad. No physical buttons involved. Confirms after the 4th digit.
The 300C RA3 label carries both serial and part number. The serial: 14 chars starting with T00AM, T00BE, or TM9. The part number (skip this): starts with P05064 or 68.
Re-read the label, especially 0 vs. O. Reach out for a free re-check if needed.
3 wrong entries lock the 300C's RA3 for 60 minutes. Keep ignition in ON or ACC for the full 60 minutes. Cutting power restarts the timer from zero.
If no code prompt appears, the lock hasn't activated. Force it by briefly pulling the radio fuse, then reconnect and turn to ON.