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Mode 01 • PID 22

OBD2 PID 0122

Fuel Rail Pressure (relative to manifold vacuum)

Definition

Mode
01 (hex)
PID
22 (hex)
Data bytes
2
Formula
((A*256)+B) * 0.079
Range
0 – 5177.265 kPa
Units
kPa

How to read PID 0122

Send mode 01 with PID 22 over OBD-II. The ECU returns 2 data byte(s), decoded with ((A*256)+B) * 0.079 (A, B, C, D are the returned bytes in order). The result is “Fuel Rail Pressure (relative to manifold vacuum)” in kPa. 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.

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