Short term secondary O2 trim — Bank 1 / 3

Last reviewed 2026-08-31

Mode 01 · PID 55 (decimal 85)

Description

Short-term secondary oxygen-sensor trim: A = bank 1, B = bank 3.

PID number

55 · 85

Unit

%

Range

-100 … 99.2

Data bytes

2

Formula

(A*100/128)-100 ; (B*100/128)-100

• 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.