DPF & EGR Removal: Which Maps to Modify (Technical Guide)

Scope of This Guide

This guide details the specific maps and parameters that are modified during DPF and EGR software removal on common Bosch diesel ECUs (EDC16 and EDC17). It’s written for tuners who need to understand the technical process.

Legal disclaimer: Disabling emissions equipment is illegal for road-use vehicles in most jurisdictions. This information is provided for off-road, competition, and educational purposes only. Always comply with your local regulations.

For a broader understanding of how these systems work, see our DPF, EGR & AdBlue guide.

DPF Removal: Map-by-Map Breakdown

1. Soot Mass Model

The ECU continuously calculates the estimated soot loading of the DPF using a mathematical model. This model uses inputs like injection quantity, engine speed, exhaust temperature, and airflow to estimate how much soot is being produced and trapped.

Maps involved:

• Base soot production rate — mg of soot produced per injection event at each operating point (RPM × injection quantity)
• Soot oxidation rate — how fast soot burns during passive regeneration (continuous oxidation at normal exhaust temperatures)
• Soot mass reset threshold — the soot loading value at which the model resets after a successful regeneration

Modification: The soot production rate map is zeroed or set to minimal values. This prevents the model from ever calculating a soot loading that exceeds the regeneration trigger threshold. Alternatively, the regeneration trigger threshold itself is set to a very high value (e.g., 999g) that can never be reached.

2. Active Regeneration Strategy

Active regeneration is the process where the ECU deliberately raises exhaust temperatures to burn trapped soot. This involves post-injection events (fuel injected after the main combustion event to heat the exhaust).

Maps involved:

• Regeneration enable/disable flag — master switch for the regen strategy
• Post-injection timing — when the additional fuel is injected (degrees after TDC)
• Post-injection quantity — how much fuel is injected for heating
• Regen target temperature — desired DPF temperature during regeneration (typically 550-650°C)
• Regen duration — maximum time for a regeneration cycle
• Regen initiation soot threshold — at what calculated soot loading to begin regen

Modification: The regeneration enable flag is set to disabled. Post-injection timing and quantity maps for regeneration are zeroed. This eliminates the fuel-wasting regen cycles. With the DPF physically removed, there’s no soot to burn, so regen serves no purpose and only wastes fuel.

3. Differential Pressure Monitoring

The differential pressure sensor measures the pressure drop across the DPF. When the DPF is removed and replaced with a straight pipe, this sensor reads near-zero differential pressure — which the ECU interprets as either a sensor fault or a damaged DPF.

Maps/parameters involved:

• Differential pressure plausibility thresholds — minimum and maximum expected pressure drop
• DPF efficiency check thresholds — expected pressure behaviour during and after regeneration

Modification: The plausibility check thresholds are widened to accept the near-zero readings, or the check is disabled entirely. On some ECUs, the differential pressure signal can be substituted with a fixed value.

4. DPF-Related Diagnostic Trouble Codes (DTCs)

Without proper software modification, removing the DPF will trigger several fault codes:

• P2002 — DPF efficiency below threshold (Bank 1)
• P2003 — DPF efficiency below threshold (Bank 2)
• P2463 — DPF soot accumulation
• P244A — DPF differential pressure too low
• P244B — DPF differential pressure too high
• P2458 — DPF regeneration duration
• P2459 — DPF regeneration frequency
• Various manufacturer-specific DTCs

Modification: Each DTC has an enable/disable flag or a trigger threshold in the calibration. These are modified to prevent the fault codes from being set. This is done either by disabling the specific DTC, or by modifying the threshold that triggers it to an impossible value.

5. DPF Warning Light

The dashboard DPF warning light is triggered by specific DTC combinations or soot loading thresholds.

Modification: The warning light trigger is disabled alongside the DTC masking.

EGR Removal: Map-by-Map Breakdown

1. EGR Valve Position Demand

The primary EGR map defines how far the EGR valve should open at each operating point.

Maps involved:

• EGR position demand map — valve opening percentage as a function of RPM and load/boost pressure
• Some ECUs have multiple EGR demand maps for different conditions (warm/cold engine, altitude, etc.)

Modification: All values in the EGR position demand maps are set to zero. The ECU never requests the valve to open. If the EGR valve has been physically removed or blanked, this prevents the ECU from expecting flow that can’t occur.

2. EGR Mass Flow Target

On some EDC17 variants, EGR is controlled by mass flow target (g/s of recirculated gas) rather than valve position percentage.

Maps involved:

• EGR mass flow target map — desired recirculated gas mass flow
• EGR mass flow correction factors — corrections for temperature, altitude, etc.

Modification: Mass flow targets are set to zero across all operating points.

3. Intake Throttle Valve (Swirl Flap)

Many diesel engines have an intake throttle valve that creates a depression (vacuum) in the intake manifold to draw exhaust gas through the EGR circuit. Without this depression, EGR gas can’t flow from the higher-pressure exhaust to the lower-pressure intake.

Maps involved:

• Intake throttle position demand — how far closed the throttle should be to create EGR depression
• Swirl flap position demand — on engines with swirl flaps, these may be coordinated with EGR

Modification: The intake throttle demand map is modified to keep the throttle fully open at all operating points. This prevents the intake restriction that was only needed for EGR flow. On some engines, this alone improves throttle response noticeably.

4. EGR-Related DTCs

• P0400 — EGR flow malfunction
• P0401 — EGR insufficient flow detected
• P0402 — EGR excessive flow detected
• P0403 — EGR circuit malfunction
• P0404 — EGR range/performance
• P0405/P0406 — EGR sensor circuit low/high
• Manufacturer-specific codes for EGR position feedback errors

Modification: DTC enable flags are disabled, or trigger thresholds modified to prevent these codes from being stored.

ECU-Specific Differences

EDC16 vs EDC17

Important: Adaptation Reset

After modifying EGR and DPF maps, the ECU’s adaptation values (learned corrections stored in EEPROM) may conflict with the new calibration. It’s recommended to:

1. Clear adaptation values using a diagnostic tool (VCDS, ISTA, etc.) after flashing
2. Clear all stored DTCs
3. Drive the vehicle for 10-20 minutes to allow the ECU to re-learn with the new calibration

Quality Indicators: What Separates Good From Bad

A professionally done DPF/EGR software removal:

• ✅ Addresses ALL related maps (not just the main demand map)
• ✅ Masks ALL related DTCs (not just the obvious ones)
• ✅ Modifies the intake throttle strategy (for EGR removal)
• ✅ Adjusts the soot model (for DPF removal) rather than just disabling regen
• ✅ Has correct checksums
• ✅ Doesn’t trigger any warning lights or limp mode

A poorly done removal:

• ❌ Only zeros the EGR demand map but leaves DTCs active → check engine light
• ❌ Only disables regen but leaves soot model active → DPF warning light after accumulation threshold
• ❌ Doesn’t modify intake throttle → ECU still creates intake depression for non-existent EGR
• ❌ Misses manufacturer-specific DTCs → intermittent warning lights

This is precisely why using a professional file service is recommended for DPF and EGR work. The complexity varies significantly between ECU variants, and missing even one parameter can result in persistent fault codes.