Firmware DTC Remover

Example 1: BMW/MINI + OBD codes

Row in firmware:
BMW/MINI: 4500 4501 4502 4503  (4 variants of same error)
OBD: 0000 0401 0000 0000  (OBD equivalent)

What you see in results:
BMW/MINI Code: 4500 | OBD Code: P0401

Our tool shows first non-empty code from each row. In this case: BMW/MINI=4500 (first), OBD=0401 (second, because first is 0000).

Example 2: Multiple OBD codes

Row in firmware:
BMW/MINI: 4BC0 4BC1 4BC2 4BC3
OBD: 0102 0103 0101 0000

What you see in results:
BMW/MINI Code: 4BC0 | OBD Code: P0102

Even though OBD row has 0102, 0103, 0101 - we show only first one (0102 → P0102). Other codes (4BC1, 4BC2, 0103, 0101) exist but are hidden.

Class table (1 byte per DTC row) — Error Path pointer

The Class byte is an index (pointer) to an Error Path — a Bosch internal parameter set that defines the full behaviour profile for this fault: whether it stores to memory, whether it lights the MIL (Check Engine), healing/debounce counters, and more.

Class = 0x3C → points to Error Path 60 (active fault, MIL on)
Class = 0x00 → no valid Error Path → fault is ignored by ECU

This is why zeroing the Class byte is the primary and safest way to disable a DTC — without it the ECU cannot look up the fault's behaviour, so the code is never stored and the Check Engine light never comes on. Our tool always zeros the Class table on every removal.

Mask table (2 bytes per DTC row) — DFC OFF Mask (detection conditions)

The Mask is a bitfield that enables or disables the diagnostic monitor (DFC — Diagnostic Function Check) for each DTC. Each bit corresponds to a specific operating condition under which the ECU is allowed to run the check.

Mask bits control:
- Whether the diagnostic monitor runs at all
- Engine warm-up / coolant temp threshold
- RPM and load operating window
- Cold start exclusion
- Number of confirmed drive cycles required

Zeroing the Mask table disables the diagnostic monitor entirely — the ECU never runs the check, so the fault can never be detected in the first place. This is zeroed when "Erase code values" is checked.

Behavior table (2 bytes per DTC row) — DFC Behavior Mask (ECU reactions)

The Behavior table defines what the ECU does when a fault becomes active. It is a bitmask where each bit enables a specific response or emergency strategy.

Behavior bits control:
- MIL (Check Engine Light) activation
- Limp mode / torque reduction (derate)
- AdBlue dosing inhibit
- DPF regeneration inhibit
- Fuel cut or boost limit activation

Not all ECU files have a separate Behavior table — when detected, the optional "Erase behavior table" checkbox appears. Zeroing it prevents limp mode and other emergency reactions even if the fault condition is still present on the sensor level.

Before deduplication (raw firmware data):

1B21 + P165A  ← Unique (different OBD codes)
1B21 + P1660  ← Unique (different OBD codes)
1B21 + N/A    ← Unique (no OBD mapping)
1B2B + N/A    ← Unique (first occurrence)
1B2B + N/A    ← DUPLICATE!
1B2B + N/A    ← DUPLICATE!

After deduplication (what you see):

1B21 + P165A  ✅ Shown
1B21 + P1660  ✅ Shown
1B21 + N/A    ✅ Shown
1B2B + N/A    ✅ Shown (first occurrence kept)