Guide
DTC off explained
Diagnostic trouble codes (DTCs, also called PCODEs) are stored by the ECU when it finds a fault. This guide explains how they are logged, what a DTC off calibration changes, and why these files are not for road vehicles.
How fault codes work
The ECU monitors sensors, actuators and emissions systems while the engine runs. When a reading falls outside its expected range, it stores a fault code and, for some faults, lights the malfunction indicator lamp (MIL).
Codes carry a status, so a fault can be current, pending or stored from an earlier drive. Reading the codes with a scan tool shows what the ECU has seen, not always what is wrong.
What a DTC off file changes
A DTC off file changes which faults the ECU reports for selected monitors. It does not repair anything, and the underlying condition is still there.
BRV Tuning supplies binary files only. Any hardware work is outside our service.
Emissions-related files are supplied for off-road, competition, agricultural and export use only, and must not be used on public roads.
These files must not be used to avoid an emissions inspection or to hide a fault on a road vehicle.
DTC off, standalone
Pricing: Master file price €35 ex VAT · slave (Tier E) €21.
The standalone DTC off file for supported passenger car ECUs.
Common codes
P0420Catalyst efficiency below threshold (Bank 1). The catalytic converter is not converting exhaust gases as well as the ECU expects.P0601Internal control module memory checksum error. The ECU found a checksum error in its own calibration memory. This is common after a file is flashed without a valid checksum.P0606Control module processor fault. The ECU reports an internal processor fault.P2002Diesel particulate filter efficiency below threshold (Bank 1). The ECU estimates the DPF is not trapping soot as well as expected.
DTC off, truck and agricultural
Pricing: Master file price €60 ex VAT · slave (Tier E) €36.
The equivalent heavy-duty calibration, priced separately. See the truck and agricultural guide.
Why a fault should not be ignored
A hidden fault can still be a sign of a real problem. A sensor may have failed, a leak may be growing, or a system may be running outside its limits.
Before you change the calibration, read and record the stored codes so you know what the ECU has logged.
Common fault codes
Codes vary by make, model and ECU. Read the stored codes on your own car before and after flashing.
P0420Catalyst efficiency below threshold (Bank 1). The catalytic converter is not converting exhaust gases as well as the ECU expects.P0601Internal control module memory checksum error. The ECU found a checksum error in its own calibration memory. This is common after a file is flashed without a valid checksum.P0606Control module processor fault. The ECU reports an internal processor fault.P2002Diesel particulate filter efficiency below threshold (Bank 1). The ECU estimates the DPF is not trapping soot as well as expected.
Questions about dtc off explained
Does a DTC off file fix the fault?
No. It changes which faults the ECU reports. The underlying condition stays and still needs diagnosis.
What does the MIL do?
The malfunction indicator lamp is the warning light on the dash. The ECU turns it on for some faults, and it can turn it off once a fault has cleared.
Can I use DTC off on a road car?
No. These files are for off-road, competition, agricultural and export use only.
See emissions-related files All questions
Emissions-related files are supplied for off-road, competition, agricultural and export use only, and must not be used on public roads.