Changan Key Programming 

How to Program All Keys Lost on Changan CS55 Using LAUNCH X431

• June 01, 2026
Step-by-step guide to programming all keys lost on Changan CS55 with LAUNCH X431. Learn PIN code reading, key programming, and troubleshooting for 2017-2023 models.

Published: June 1, 2026

How to Program All Keys Lost on the Changan CS55 Using LAUNCH X431

Quick Answer: The All Keys Lost Solution

If you have lost every key for your Changan CS55, a LAUNCH X431 diagnostic scanner can generate a new key in about 5–10 minutes—no original key required. The critical requirement is the vehicle's 20-digit Security PIN code, which the tool can read from the BCM or ECU. You'll need a compatible X431 model (PAD VII, PRO3, or V+) with updated software and a blank transponder key. Once programmed, the new key will start the engine and operate the locks.

What You Need Before You Start

Before diving into the procedure, gather the following essentials. Skipping any of these steps is the number one reason programming fails.

Compatible LAUNCH X431 Tool

Not every X431 model handles "All Keys Lost" recovery. The following models are confirmed to work:

  • LAUNCH X431 PAD VII (best overall stability)
  • LAUNCH X431 PRO3
  • LAUNCH X431 V+
  • LAUNCH X431 IMM (immobilizer-focused version)

Avoid using standard Creader or Diagun units—they lack the necessary "All Systems" and "ECU Coding" functions.

Tool and Vehicle Preparation

  • Software update: Connect your X431 to Wi-Fi, go to Software Update, and ensure the Changan (or ChangAn) module is up to date. An outdated module may fail to read the PIN.
  • Battery health: The vehicle's 12V battery must read above 12.3V. Below that, the BCM may drop communication mid-programming. Use a multimeter or the X431's battery voltage display to check.

The 20-Digit Security PIN Code

You cannot program a key without this code. The PIN is unique per vehicle and stored in the BCM or ECU. The X431 can read it directly (see Step 2), but if that fails, you'll need to get the code from a Changan dealership or a paid VIN-based lookup service. Write it down immediately—do not rely on memory.

Blank Key Requirements

You'll need a compatible uncut transponder key for the Changan CS55. Most CS55 models (2017-2023) use:

  • Chip type: 4D-60 or 46 chip (sometimes labeled as 4C)
  • FCC ID: Check your original remote's FCC ID if you still have a broken key; otherwise, buy a key listed for your specific model year.

Buy from a reputable locksmith supplier. Cheap knockoff blanks often have weak transponder chips that fail the learning process.

Step-by-Step: Programming All Keys Lost on Changan CS55

Follow these steps in order. If you get stuck, refer to the troubleshooting section later.

Step 1: Connect and Identify the Vehicle

  1. Plug the LAUNCH X431 into the OBD-II port located under the driver's dashboard.
  2. Power on the tool and select Diagnostics from the home screen.
  3. Choose Changan (or ChangAn Auto depending on your software version).
  4. Select CS55 and confirm the model year if prompted.
  5. Let the tool perform an automatic ECU scan. Wait until the "All Systems" list appears—this confirms communication with all modules.

Tip: Use a short OBD-II extension cable if you have trouble reaching the port. Avoid USB extension cables—they can introduce signal noise.

Step 2: Read the Security PIN Code

This is the make-or-break step. Without the correct PIN, you cannot add a new key.

  1. From the system selection screen, navigate to Special Functions or Immobilizer.
  2. Select Read Security Code or Read PIN Code. (The exact wording varies by firmware version.)
  3. The tool will ask you to connect to the BCM or ECU. Choose the BCM first—it usually responds faster.
  4. Follow the on-screen prompts. The X431 will scan the module and display a 20-digit alphanumeric code.
  5. Take a photo or write the code on paper immediately. Do not rely on the tool's memory—it may clear after exiting the menu.

What if the tool cannot read the PIN? Try switching to the ECU instead of BCM. If both fail, the software may be outdated, or the vehicle uses an encrypted BCM that requires dealer-level access. In that case, contact a Changan dealership with your VIN.

Step 3: Initiate the "All Keys Lost" Function

  1. Return to the main diagnostic menu, go to Immobilizer, then Key Programming.
  2. Select All Keys Lost or Erase All Keys & Program New.
  3. The tool will warn you: "This will delete all existing keys from the vehicle memory." Since you have no usable keys, confirm to proceed.
  4. The system now enters key learning mode. The dashboard may flash or beep—this is normal.

Step 4: Program the New Key

  1. Insert the blank Changan key into the ignition slot. For push-button start models, hold the key near the start button or inside the key pocket (typically in the center console).
  2. The X431 will prompt you to enter the 20-digit Security PIN obtained in Step 2.
  3. Enter the code slowly and carefully. A single wrong character can lock the immobilizer for 10–15 minutes.
  4. After successful PIN verification, the tool displays: "Turn Ignition ON" or "Press Start Button Once." Do exactly that.
  5. Wait 5–10 seconds. The tool will show "Key Learning Successful" or "Programming Complete."
  6. If you have a second blank key, the tool will ask: "Insert Next Key?" Repeat the process. Most CS55 models allow up to four keys.

Step 5: Test and Finalize

  1. Turn the ignition off and remove the key.
  2. Wait 30 seconds to let the BCM save the new information.
  3. Insert the newly programmed key and start the engine. It should crank and run without hesitation.
  4. Test all functions: remote lock/unlock, trunk release, panic button, and keyless entry.
  5. If the remote buttons don't work, proceed to Remote Control Programming under the same Immobilizer menu. Follow the pairing procedure (usually press Lock + Unlock together for 3 seconds until the car beeps).

Troubleshooting Common Issues

Even experienced technicians hit snags. Here's how to handle the most common problems.

"Communication Error" or "Unable to Read PIN"

Likely cause: Incompatible tool, outdated software, or weak OBD connection.

Fix:

  • Update the Changan software module on the X431.
  • In tool settings, switch to High Speed CAN mode (some BCMs require it).
  • Use an OBD-II extension cable—avoid extension cables that carry USB signals.
  • If the error persists, the vehicle may have a locked BCM requiring a dealer code reset.

"Security PIN Locked" – Too Many Attempts

Likely cause: Entering the wrong PIN three or more times.

Fix:

  • Turn the ignition OFF and remove the key. Do not touch anything for at least 30 minutes.
  • After the lockout timer expires, you can try again. If you still get locked out, the PIN you have is incorrect—obtain a fresh one from a dealer or VIN lookup service.
  • Avoid guessing. Each failed attempt adds to the lockout time.

Key Starts Engine but Remote Lock/Unlock Fails

Likely cause: The immobilizer chip was programmed, but the remote control pairing step was skipped.

Fix:

  • Navigate to Immobilizer > Remote Control > Add Remote on the X431.
  • Follow the on-screen sequence: usually turn ignition on/off, then press a button on the remote.
  • Ensure your blank key has the correct FCC ID for Changan CS55. If the ID is wrong, the vehicle will ignore the remote signal.

"Key Not Recognized" After Programming

Likely cause: Damaged transponder chip, incorrect key blank, or incomplete learning session.

Fix:

  • Verify the chip type—use a known good blank from a locksmith.
  • If you have one programmed key, use the Add Key function instead of starting from scratch.
  • Perform a full battery reset: disconnect the negative battery terminal for 5 minutes, reconnect, and try the programming again.

FAQ: Changan CS55 Key Programming with LAUNCH X431

1. Can I program a key for a Changan CS55 without the original key?

Yes. The LAUNCH X431's "All Keys Lost" function is designed for exactly this situation. You need only a blank transponder key and the vehicle's 20-digit Security PIN. No original key is required.

2. Where can I get the Security PIN for my Changan CS55?

The easiest way is to read it directly using the X431 (see Step 2). If the tool fails, contact a Changan dealership and provide your VIN. Some online PIN code lookup services also offer instant delivery for a small fee. The PIN is always 20 characters long.

3. Is the LAUNCH X431 V+ or PRO3 better for this job?

Both are capable. The X431 PAD VII is the gold standard for "All Keys Lost" due to its faster processor and more stable ECU connection. The V+ and PRO3 are also reliable but may take slightly longer during the PIN reading phase on certain BCM versions. If you do this regularly, invest in the PAD VII. For occasional use, the PRO3 or V+ will suffice.

4. How long does the process take?

From connecting the tool to starting the engine, expect 5–10 minutes. Including the PIN reading step, plan for 15–20 minutes total. The actual programming takes less than two minutes.

5. Will the remote central locking work after programming?

Yes, but only if you complete the Remote Code Learning step. Many users skip this and wonder why the doors don't lock. After programming the immobilizer, go to Immobilizer > Remote Control and pair the remote(s). The procedure typically involves pressing Lock and Unlock simultaneously for three seconds.

6. Can a mechanic or locksmith do this?

Absolutely. Many mobile locksmiths and automotive technicians carry LAUNCH X431 tools. It's considered a professional-grade diagnostic scanner. DIY users with mechanical experience can also follow this guide—just take your time with the PIN entry.

7. What if I enter the wrong PIN?

The tool will block further attempts for 10–15 minutes. After that, you can try again. Exceeding the allowed number of attempts (usually 3–5) may require the ignition to be off for one hour. Always double-check the PIN before entering it.

8. Does this work on all Changan CS55 model years?

It works reliably on 2017 to 2023 models. For very new models (2024+) or older ones (pre-2017), check your X431 software compatibility. The LAUNCH X431 covers most global CS55 variants, but some China-only early models may use a different immobilizer protocol. If in doubt, contact LAUNCH support with your VIN.

Final Checklist Before Programming

  • LAUNCH X431 fully charged and updated with the latest Changan software.
  • Vehicle battery voltage above 12.3V (test with multimeter or tool).
  • At least one blank Changan CS55 transponder key (4D-60 or 46 chip).
  • Security PIN code (20-digit) obtained and written down.
  • Stable OBD-II connection (extension cable if needed).
  • Work area free from strong radio interference (avoid parking near cell towers).

Conclusion: DIY or Pro?

Programming all keys lost on the Changan CS55 using the LAUNCH X431 is a manageable task for a determined enthusiast—but it demands precision. The security PIN is the gatekeeper, and one wrong digit can lock you out for an hour. If you're comfortable following diagnostic tool prompts, you can save a dealership visit fee.

However, if you cannot obtain the PIN, or if the X431 fails to communicate after multiple attempts, don't force it. Call a professional automotive locksmith or a Changan dealership. They have direct access to manufacturer databases and can guarantee the job in one visit.

For most independent technicians and serious DIYers, the LAUNCH X431 is the best tool for the job—it pays for itself after a single key programming session.

About the Author: Erwin Salarda is an Automotive Service Equipment Technician based in the Philippines, specializing in computerized automotive diagnostic equipment such as OBD scanners and wheel alignment systems. Since 2012, he has been actively providing technical support, equipment installation, troubleshooting, after-sales service, and hands-on training for automotive service equipment used by workshops and automotive professionals.

He has received specialized training from international suppliers and manufacturers, including Launch X431 in Shenzhen, China, Lawrence Engineering Company in Guangzhou, China, and 3Excel Wheel Alignment Company in Shenzhen, China. Through these trainings, he developed advanced expertise in automotive diagnostics, calibration, wheel alignment systems, and computerized automotive service technologies.

Erwin Salarda provides professional after-sales support and technical training for automotive diagnostic and wheel alignment equipment, helping clients maximize the performance and proper use of their tools and systems. His experience covers equipment setup, software updates, calibration procedures, troubleshooting, and operational guidance for automotive workshops and service centers.

With more than a decade of experience in the automotive equipment industry, Erwin Salarda continues to support automotive businesses by delivering reliable technical expertise and practical training solutions.

For inquiries and equipment purchases, please visit https://carlifterph.com/

Disclaimer: This guide is for informational purposes only. Incorrect programming can lock the immobilizer and require dealer intervention. Always back up original data if possible. Contact LAUNCH support or a certified technician for advanced issues.

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