MODE 01 · PID 06

Short-term fuel trim · bank 1

A positive signed fuel trim represents fuel being added relative to the base calculation. A negative reading represents fuel being removed.

Formula
A × 100 / 128 − 100
Data bytes
1
Units
%

A worked decoding example

Request: 01 06

Response: 41 06 90

Data: 90 → 12.5 %

The example shows service, PID and data only. It omits adapter headers, CAN identifier, length and padding. It is not a live vehicle reading.

Reading context

Record closed-loop status and engine speed. Do not interpret an open-loop, unsupported or frozen value as a confirmed mixture fault.

A decoded value is a measurement, not a diagnosis. Encoding limits are not normal operating limits. Confirm vehicle support and the manufacturer’s procedure.

Byte decoder

Your input stays in this browser.MODE 01

FormulaA × 100 / 128 − 100 → %

A decoded value is a measurement, not a diagnosis. Encoding limits are not normal operating limits. Confirm vehicle support and the manufacturer’s procedure.

Sources

  1. python-OBD: Mode 01 command table ↗
  2. python-OBD: byte decoding implementation ↗
  3. CSS Electronics: OBD-II PID and response frames ↗
  4. California BAR: OBD test reference ↗

Independent reference; no affiliation with SAE, vehicle manufacturers or regulators. Sources checked 28 October 2026.