MODE 01 / SAE J1979
PID reference
From response bytes to physical values. Learn what a scanner reading means, how it is calculated, and what context to record.
Detailed technical references are currently available in English and Chinese.
16 PIDs · MODE 01
| PID | PID reference | Units | Formula | |
|---|---|---|---|---|
04 | Calculated engine load | % | A × 100 / 255 | ↗ |
05 | Engine coolant temperature | °C | A − 40 | ↗ |
06 | Short-term fuel trim · bank 1 | % | A × 100 / 128 − 100 | ↗ |
07 | Long-term fuel trim · bank 1 | % | A × 100 / 128 − 100 | ↗ |
0B | Intake manifold absolute pressure | kPa | A | ↗ |
0C | Engine speed | rpm | (256 × A + B) / 4 | ↗ |
0D | Vehicle speed | km/h | A | ↗ |
0E | Timing advance | ° | A / 2 − 64 | ↗ |
0F | Intake air temperature | °C | A − 40 | ↗ |
10 | Mass air flow | g/s | (256 × A + B) / 100 | ↗ |
11 | Absolute throttle position | % | A × 100 / 255 | ↗ |
1F | Run time since engine start | s | 256 × A + B | ↗ |
21 | Distance with MIL on | km | 256 × A + B | ↗ |
2F | Fuel tank level input | % | A × 100 / 255 | ↗ |
42 | Control module voltage | V | (256 × A + B) / 1000 | ↗ |
46 | Ambient air temperature | °C | A − 40 | ↗ |
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.