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Mode 01 • PID 21

OBD2 PID 0121

Distance traveled with MIL on

Definition

Mode
01 (hex)
PID
21 (hex)
Data bytes
2
Formula
(A*256)+B
Range
0 – 65535 km
Units
km

How to read PID 0121

Send mode 01 with PID 21 over OBD-II. The ECU returns 2 data byte(s), decoded with (A*256)+B (A, B, C, D are the returned bytes in order). The result is “Distance traveled with MIL on” in km. This is standard SAE J1979 data supported by most OBD-II scan tools and loggers.

Why it matters for tuning

Live PIDs like this are how tuners and workshops verify a remap on the road — logging RPM, load, boost, lambda and temperatures to confirm the map is safe. The desktop Softechpro Solutions software complements live logging with offline ECU editing: DPF/EGR/AdBlue/DTC off and Stage tuning with automatic checksum.

Related PIDs

011D Oxygen sensors present011E Auxiliary input status011F Run time since engine 0120 PIDs supported 21-400122 Fuel Rail Pressure (re0123 Fuel Rail Pressure (di0124 O2S1_WR_lambda(1): Equ0125 O2S2_WR_lambda(1): Equ

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