12 min · 2026-09-02 · ChiptuningLab desk
DTC off in an ECU file: which codes a workshop can actually put on the ticket
Nobody maps ‘all DTCs’. You send the scan, we switch off the monitors that match hardware you removed. Circuit and motorsport. Not a MOT sticker.
Look up P0401, P2002, P20EE on the DTC list →
Reviewed by the lab desk before it went live. We write files; we do not rubber-stamp brochure numbers.
Workshops ask for a list of every DTC and a switch that turns them all off. That list is thousands of codes. SAE J2012 plus manufacturer P1/P2/U families. Putting them on one page does not write a file. The file cares about the codes on your scan and the parts that left the car.
A DTC is the ECU saying a monitor failed. P-codes are powertrain. B-codes are body. C-codes are chassis. U-codes are the network between boxes. An EGR-off file is not a DTC-off file. One stops the valve request. The other stops a code coming back after the valve is already gone. Workshops often need both on the same Saturday. Write both on the same ticket.
What the option actually does: we mask or disable the monitors tied to hardware you removed on a track or off-road build. What it does not do: repair a dead sensor, quiet an airbag light, invent a passing annual test, or hide a boost leak you have not found. ‘Make the dash dark’ is not a parts list.
How to read the first letter. P0 is generic powertrain — P0420 catalyst, P0401 EGR flow, P0130 lambda. P1 is manufacturer powertrain, the codes two scanners name differently. P2 is still powertrain, often DPF, NOx, swirl, AdBlue — P2002, P20EE, P2015. P3 is rarely the ticket. B0/B1 is body and airbag. C0/C1 is ABS and steering. U01xx is a box that stopped talking. We do not treat a U0101 like a P2453.
DPF family, when the can is gone: P2002 particulate efficiency, P2452/P2453 differential pressure sensor, P2458 regeneration duration, P2463 soot accumulation, P242F DPF restriction. Cousin on petrol GPF/OPF is its own option, not a copied diesel bin. See the DPF-off note on this blog if the filter itself left the car.
EGR family, when the valve or cooler is blanked: P0401 insufficient flow, P0402 excessive flow, P0403 circuit, P0404 range, P0405/P0406 position sensor. Swirl and intake flaps sit next door — P2004, P2006, P2015, P2016. A swirl code on a car that still has the flaps is a mechanical job, not a file.
AdBlue / SCR / NOx family, Euro 6 diesels: P20EE SCR NOx efficiency, P207F quality, P203A–P203E tank level and quality sensor, P2200–P2203 NOx sensor, plus the countdown codes each group names differently — BMW, VW, Mercedes OM654, Peugeot BlueHDi. Tank gone, injector blanked, sensors still there or not: write that sentence. The AdBlue-off article on this desk is the pair to this list.
Lambda and catalyst family, usually petrol or a mixed build: P0130–P0135 and P0150–P0155 bank 1 and 2 sensors and heaters, P0140/P0160 idle activity, P0420/P0430 catalyst efficiency. A P0420 on a stock downpipe is often a tired cat, not a map. A P0420 after you fitted a sports cat or a pipe is a ticket we can talk about, with the hardware named.
Boost, airflow, fuel — codes a file should not swallow. P0234 overboost, P0299 underboost, P0100–P0103 MAF, P0171/P0174 mixture lean, P0300–P0308 misfire. Those are pipes, clamps, a dirty meter, a coil. Masking them is how a customer comes back with a hole in a piston and a screenshot of a clear dash.
Gearbox and network. A DSG that still protects 380 Nm will throw its own family after an engine file. That is a TCU ticket, not DTC-off on the engine dump. U0100/U0101 lost communication with ECM/TCM is wiring or a box that is off, not a monitor we tick from here. Airbag B-codes and ABS C-codes stay off this option unless the job is the airbag service on the menu, on its own ticket.
How a useful ticket looks. Paste the freeze-frame or the scan PDF. List the codes in the notes — P2453, P2002, P0401, not ‘a few emissions lights’. Say what you physically removed. Attach the full ECU read, same tool you will write back with. Autotuner in, Autotuner out. A 200 kb snippet is not a scan and it is not a dump.
On this menu DTC-off sits as an option next to DPF, EGR, AdBlue, GPF, lambda, swirl. Stage 1 and Stage 2 bundles can carry the free options when they apply. Credits leave when you open the request. Rejected work puts them back. Open an account, drop credits in the wallet, open the ticket, put the codes on it. That is the whole path.
Circuit and motorsport only. A dark dash is not a street ticket and it is not type approval. If the customer wants brochure behaviour back, flash the virgin dump you kept on day one or order the original-file service. The DTC button is not a time machine and it is not an annual-test cheat.