Transmission actual gear
Last reviewed 2026-08-31
Mode 01 · PID A4 (decimal 164)
Description
Actual transmission gear ratio when bit A1 is set.
- PID number
- A4 · 164
- Unit
- ratio
- Range
- 0 … 65.535
- Data bytes
- 4
- Formula
- [A1]=supported ; ((C*256)+D)/1000
- Also valid as Mode 02 freeze-frame data (same PID number, snapshot at last DTC).
Defined by SAE J1979 / ISO 15031-5. Public index — not a substitute for the paid SAE document.
Sources
Provenance for this page. Official standards outrank community notes. See the confidence policy.
Official standard · high trust
SAE J1979 / ISO 15031-5 Mode 01 PID formulas (public index)
J1979 public PID index: 01 A4