# P0135 — O2 Sensor Heater Circuit (Bank 1, Sensor 1)

> ClearTheCode diagnostic code reference (not OEM service data).

Source: https://clearthecode.com/codes/P0135

**System:** Powertrain · Fuel & Air Metering

**Severity:** minor

## Description

Internal heater in the O2 sensor has failed. Replace the sensor; also check the heater fuse.

## Diagnostic snapshot

- **Difficulty:** 6/10 — Intermediate diagnostics
- **Est. repair cost:** $120 – $450

## Diagnostic workflow

1. Confirm P0135 with a live scan — note pending vs stored and freeze frame data.
2. Inspect wiring/connectors and related sensors before replacing modules.
3. Clear codes and road-test; re-scan after two drive cycles if the monitor must set.

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