MODE 01 · PID 07
Long-term fuel trim · bank 1
Long-term fuel trim is a learned correction. ECU learning cells and reset behaviour vary by vehicle.
- Formula
A × 100 / 128 − 100- Data bytes
- 1
- Units
- %
A worked decoding example
Request: 01 07
Response: 41 07 88
Data: 88 → 6.25 %
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
Capture the operating state and short-term trim at the same time. Do not add readings from different banks or different operating conditions.
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
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
- python-OBD: Mode 01 command table ↗
- python-OBD: byte decoding implementation ↗
- CSS Electronics: OBD-II PID and response frames ↗
- California BAR: OBD test reference ↗
Independent reference; no affiliation with SAE, vehicle manufacturers or regulators. Sources checked 28 October 2026.