Learn how to delete DTC codes from Simos 18 using WinOLS ,complete breakdown and live demo
dtc-delete-simos18

What Cars Use Siemens Simos 18?

The Siemens Simos 18 ECU is commonly found in turbocharged Volkswagen Group vehicles, including Audi, Skoda, and Seat. It's a high performance ECU designed for precision, but it often floods the system with fault codes,especially after hardware upgrades.

You'll find Simos 18 in models like:

• Volkswagen Golf 7 / Beetle / Jetta / Passat B8 / Polo / Sharan / Tiguan
• Audi A3 / TT / A6 / Q5 / S3
• Skoda Octavia / Superb

These ECUs are highly sensitive to changes in exhaust, air intake, and emissions systems, leading to common trouble codes.

Most Common DTCs in Simos 18 ECUs

1. P0420 – Catalyst Efficiency Fault
2. P0036 to P0039 – Second Lambda Sensor Faults
3. P0136 to P0139 – Lambda Sensor Heater Faults
4. P0300 to P0304 – Cylinder Misfire Detection
5. P0403 – EGR Circuit Malfunction

These codes are typically triggered after installing decat pipes, downpipes, or custom tuning, resulting in persistent check engine lights even when everything runs perfectly.

What Software Is Used to Remove DTCs from Simos 18?

The best tool for the job is WinOLS. It allows you to precisely edit raw ECU dumps to locate, isolate, and remove fault codes in a way that keeps the system stable and prevents false triggers,while preserving the functionality of other diagnostics.

How to DTC OFF for Siemens Simos 18?

In Simos 18 ECUs, DTC removal involves three key areas inside the ECU dump:

1. DTC Table (Error Codes Area)
2. First Counter Area (Before the Table)
3. Third Counter Area (After the Table)

This is more complex than older Bosch or Siemens ECUs, but you’ll learn exactly how to handle it inside our tutorial.

Here’s what we teach in the course:
 How to identify error codes (e.g., 0420, 0136) in 16-bit hex view
 How to locate counters using 8-bit hex view and visual pattern recognition
 How to duplicate the DTC table when more than 512 codes are present
 How to split large DTC tables—Simos18 often has ~1000 error codes split into 2 tables
 How to link counters with error codes so disabling one doesn’t trigger another
 How to validate the changes by checking indicators that ensure proper DTC linking

This method ensures that the check engine light is turned off, the error doesn’t come back, and the car continues operating normally, with no limp mode, no side effects, and no loss of performance.

Why Is DTC OFF Important in Simos 18?

With stricter emissions monitoring, modern Simos 18 ECUs throw DTCs even when everything’s fine, especially after upgrades like:

• Aftermarket exhausts
• Turbo and intake mods
• Disabled secondary O2 sensors
• Removed EGR or catalytic converters

Instead of spending hours trying to solve ghost issues, you’ll learn to surgically remove the exact fault codes that matter, without compromising the rest of the system.

 DTC Removal Tutorial for Siemens Simos 18

In this video and course, you’ll learn step-by-step how to handle one of the most advanced DTC OFF jobs in tuning: Siemens Simos 18. This ECU is packed with hidden traps, but we’ll show you how to decode, split, and fully disable over 900 fault codes in a safe, stable way.

 If you’re serious about becoming a true ECU professional, Simos 18 is not optional.
 This course shows you how to master what 90% of tuners still struggle with.

 Join the course and get ahead of the curve, because Simos 18 is the future of VAG tuning.

 How to Permanently Delete ECU Codes

Deleting codes in Simos 18 isn't just about zeroing out the DTC. You must locate the linked counter bytes and match them with logic triggers otherwise, codes reappear or worse, corrupt the diagnostics.
Our course teaches you to permanently disable DTCs by isolating them from pre  and post evaluation blocks, giving you clean, stable operation even after long-term use or dealer-level diagnostics.

 WinOLS Mappack

This training includes a full WinOLS mappack for Simos 18 that covers:

• DTC table structure and splits
• Counter maps
• Diagnostic enable/disable flags
• Split-table logic zones for 1K+ error code systems

You’ll save massive time on each file and eliminate the risk of mistakes—no more trial and error. Just precision edits with fully labeled map areas ready to use.

 Support: Your Simos18 Experts Are Here

If you're stuck decoding a Simos 18 file, or just want a second opinion before writing a modified dump we’ve got your back. Our Schiller-Tuning team provides professional support from real-world projects across hundreds of VAG vehicles.

 File checkups
 Custom solution files
 ECU recovery help
 Real answers from experienced engineers

 Message us any time and let’s make sure your DTC OFF job is done right the first time.

 Enroll now and unlock the full Simos 18 DTC OFF course
 Mappack + live support included
 Only at Schiller-Tuning.com