P1170 — Front HO2S (Bank 1 Sensor 1) Circuit Fixed / Inactive
CAUTIONIs it safe to drive? Drive gently and get it looked at soon — it can worsen or fail inspection.
What P1170 means
This is a manufacturer-specific code — its meaning depends on the vehicle’s make (see below).
What P1170 means on specific makes
Mazda CAUTION
The front oxygen sensor signal on Bank 1 is stuck/fixed (not switching), so the PCM can't run closed-loop fuel control. Usually a worn or contaminated front O2/A-F sensor. P1173 is the Bank 2 version.
- Failed/contaminated front O2 sensor ($80-250)
- Exhaust leak near sensor
- Wiring/connector fault
- Underlying lean/rich cause
Check first: Watch the front O2 sensor switching in live data; a flat trace means replace the sensor (after ruling out exhaust leaks).
Source: shadetreespeedshop.com/mazda-check-engine-light, miata.net