[Update] OBD tools that read key code for 1991 Mercedes Benz SL500

2572 views - Last reply: May 09, 2025
This topic is closed for new replies.

How do I find the key code to program a key for my 1991 Mercedes Benz SL500?

Hello! We've developed a VIN-based tool to help you get your key code for the 1991 Mercedes Benz SL500. Check it out here: VIN Key Code Generator.

Replies (6)

I think my 1991 Mercedes Benz SL500 has the same issue. Good to know I'm not alone.

Just wanted to say this guide helped with my 1991 Mercedes Benz SL500!

If this works for my 1991 Mercedes Benz SL500, I owe you big time.

Bookmarking this for when I work on my 1991 Mercedes Benz SL500 this weekend.

My mechanic said this might help with my 1991 Mercedes Benz SL500 key issue.

I’ll try this and update how it goes with my 1991 Mercedes Benz SL500.

Check the news !

Lowrider Spectacular
🚙 Local Meetup: Lowrider Spectacular
A gathering for true gearheads and petrolheads

🏁 Where: City Park Pavilion
📆 When: August 19 @ 10AM-4PM

Event features:
Kids Activities | Charity Fundraiser

⚙️ Forum Members: Forum members get preferred parking! ✨

🔩 Classic Car Restoration Workshop

👩‍🏭 Instructors:
• Race Engineer Emily Torres
• Restoration Pro Alex Petrov

⚙️ Hands-On Activities:
• Interior restoration techniques
• 4-hour intensive training
• Personal coaching

📋 Skills Covered:
Leather repair | Headliner replacement | Trim restoration

🏎️ August 11, 2026 at 11:00 AM (4-hour)

💡 Special discounts on tools for participants!

Workshop: Classic Car Restoration Workshop
ECU Remapping Masterclass

🔋 ECU Remapping Masterclass

🧰 Instructor: Dyno Operator of the Year Dave Wilson

📱 Workshop Includes:
• Emission-legal power gains
• 4-hour intensive hands-on training
• Cooling system optimization | Heat management

📉 Bonus: Exclusive tuner network discounts

🔌 Next Session: August 1, 2026 at 12:00 PM

Customize Your Tuning Focus:

🚀 Performance Mod Cost Estimator

Pro Tip: Supporting mods (fuel system, cooling) are often needed for big power gains

Vehicle Information

Modification Information

Additional Options

🔑 Car Key & Fob FAQ

Common questions about key programming, fob issues, and replacement options

Key Programming
Some vehicles allow DIY key programming using specific sequences (like turning ignition on/off with original keys). However, most modern cars require specialized equipment only locksmiths or dealers have. Check your owner's manual for your specific model.
Key Tip: Replace key fob batteries every 1-2 years as preventative maintenance
Key Programming
Professional key programming requires: diagnostic tools to access the immobilizer system, key code software, transponder programmers, and often proprietary manufacturer equipment. Some locksmiths and all dealers have these tools.
Key Tip: Some locksmiths offer mobile key programming services
Security Systems
A flashing security light often indicates an immobilizer issue. Solid light suggests the system is armed but not recognizing your key. Causes: faulty key chip, damaged antenna ring, low battery, or system needs reprogramming.
Key Fob Issues
Common causes: dead battery (most common), water damage, internal circuit damage, or the fob lost synchronization with your car. Try replacing the battery first. If that doesn't help, the fob may need reprogramming or replacement.
Key Tip: Newer cars often require dealer programming for first key replacement
Key Fob Issues
1) Find the seam and pry open the fob (some have tiny screws) 2) Note battery orientation 3) Remove old battery (CR2032 is most common) 4) Insert new battery 5) Reassemble. Test all buttons - if issues remain, the fob may need reprogramming.
Key Tip: Replace key fob batteries every 1-2 years as preventative maintenance
Key Fact: Some insurance policies offer key replacement coverage

🔑 KEY SERVICES CLASSIFIEDS

Key Fob Repair & Battery Replacement
$25+
Posted: Jul 23, 2026
Fob not working? We fix broken buttons, replace batteries, and resync to your vehicle. Most repairs done while you wait. Water damage specialists available.
Call: 962-837-9827
Smart Key Programming Special
$150
Posted: Jul 23, 2026
Push-to-start key replacement for Toyota, Honda, Nissan, Ford. Includes programming and testing. Limited time offer - normally $200+. Call for availability.
Call: 347-776-9464
Car Key Extraction Service
$45+
Posted: Jul 20, 2026
Broken key stuck in ignition or door? We can remove it without damage and make new keys same day. Emergency service available 24/7 for lockouts.
Call: 816-231-6442
Key Fob Case Replacement
$35
Posted: Jul 21, 2026
Cracked or damaged fob housing? We transfer your electronics to a new case. Multiple color options available. Most models in stock. 15-minute service.
Call: 573-635-5317
Ads refreshed daily • Licensed professionals • Mobile services available

🔑 Upcoming Key & Immobilizer Services

Workshop
Aug 4, 2026

Transponder Key Tech Day

by Auto Key Masters
Hands-on experience with the newest transponder key cloning and programming equipment
Seminar
Aug 7, 2026

Anti-Theft System Demonstration

by Mobile Key Tech
Become certified in vehicle security systems with our intensive 2-day course
Seminar
Aug 9, 2026

Key Fob Repair Training

by The Key Lab
Hands-on training for programming transponder keys, smart keys, and fobs using professional tools
Seminar
Aug 1, 2026

VIN Decoding Workshop

by Car Key Solutions
Step-by-step instruction for repairing common key fob issues including button and circuit problems

Need immediate service? Call our 24/7 hotline: 1-800-KEY-HELP

Want to list your key service? Join our provider network

Last posts on the forum