Bosch MED17.4.x ECUs are widely used across PSA Group vehicles, including Peugeot, Citroën, and MINI petrol platforms. These ECUs deliver excellent performance control, but they are also highly sensitive to exhaust and emissions modifications.

After common upgrades such as decat systems, second lambda deletes, or EGR removal, MED17 based PSA vehicles frequently trigger persistent fault codes that cannot be solved with basic diagnostic tools.

 Bosch MED17 DTC OFF / Delete for PSA Petrol ECUs

In this dedicated lecture, you will learn how to permanently delete Diagnostic Trouble Codes (DTCs) from Bosch MED17 PSA ECUs using WinOLS, applying a precise, firmware level approach used by professional tuners.

This lecture is part of the WinOLS DTC Removal / Fault Code Delete Course for Gasoline ECUs, with a specific focus on PSA Group MED17 logic.

Understanding DTC Logic in PSA Bosch MED17 ECUs

Bosch MED17 ECUs used in PSA vehicles rely on dual layer diagnostic logic. To perform correct DTC OFF, you must understand both layers.

In this lecture, you will learn:

• How DTC codes are stored as 16-bit linear sequences
• How 8-bit counter areas control fault activation
• Why MED17.4.2 often requires two separate DTC tables
• Why random hex editing leads to unstable diagnostics

This understanding is critical for clean, permanent, and professional DTC removal.

DTC OFF for Bosch MED17 (PSA) Using WinOLS

This tutorial demonstrates a structured WinOLS workflow using real PSA MED17 ECU files. You will learn how to:

• Locate DTC tables using 16-bit HEX search (e.g. 2177, 2178, 0606)
• Identify dense counter blocks in 8-bit view
• Correctly match each DTC to its corresponding counter
• Disable fault codes by zeroing both code and counter logic
• Validate that DTCs do not return after resets or diagnostics

This is real DTC OFF work, not theory.

PSA Vehicles Using Bosch MED17 ECUs

Bosch MED17 ECUs are commonly found in the following PSA Group vehicles:

Peugeot

207 RC, 208, 308, 408, 508, RCZ, 3008, 2008

Citroën

C3, C4, C5, DS3, DS4, DS5

MINI

Cooper S, ONE

If you tune or repair PSA petrol vehicles, mastering MED17 DTC OFF is essential.

Common Fault Codes in PSA MED17 ECUs

The most frequently deleted DTCs include:

• P0420 – Catalyst efficiency fault
• P0036–P0039 – Second lambda sensor faults
• P0136–P0139 – Lambda heater circuit faults
• P0300–P0304 – Random and cylinder-specific misfires

These faults typically appear after exhaust or emissions changes, even when the engine runs perfectly.

Why DTC OFF Is Essential on PSA MED17

PSA MED17 ECUs are calibrated for strict emissions compliance. After modifications such as:

• Decat exhaust systems
• Secondary lambda deletes
• EGR removal

the ECU continues to detect faults that no longer apply.

Proper DTC OFF allows you to:

• Eliminate false catalyst and lambda errors
• Prevent repeated Check Engine Lights
• Maintain stable drivability
• Deliver professional, comeback-free tuning files

Permanent DTC Deletion on Bosch MED17 (PSA)

Permanent DTC OFF means removing the trigger, not just the warning.

In this lecture, you will learn how to:

• Identify DTC and counter areas correctly
• Build clean, traceable DTC tables
• Zero out activation logic safely
• Validate that diagnostics remain stable

When done correctly:
    No CEL
    No pending faults
    No return after drive cycles

WinOLS Mappack for PSA MED17 DTC OFF

To eliminate guesswork, this lecture includes a custom WinOLS mappack designed specifically for PSA MED17 ECUs, featuring:

• Pre-aligned DTC and counter axes
• Clean map structure for fast identification
• Ready-to-use DTC OFF zones
• Support for MED17.4.2 and related variants

Even advanced WinOLS users will save hours of work with this mappack.

Professional Support from Schiller Tuning

At Schiller Tuning, training is based on real files and real projects.

You get:

• Help with catalyst and lambda faults
• Assistance matching counters correctly
• File review and troubleshooting support

Whether you’re stuck or want confirmation, we’re here to help.

What You Will Learn in This PSA MED17 Lecture

After completing this episode, you will be able to:

 Identify PSA MED17 DTC and counter structures
 Permanently delete catalyst and lambda fault codes
 Disable misfire and emissions-related DTCs
 Prevent CEL and unstable diagnostics
 Perform professional DTC OFF for PSA petrol vehicles

 Watch the tutorial, follow the workflow, and master PSA MED17 DTC OFF
Only at Schiller Tuning ,real WinOLS training, no guesswork.