P0135 on Toyota
O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
P0135 on Toyota vehicles indicates o2 sensor heater circuit malfunction (bank 1, sensor 1). Au7o has documented this code across 1 Toyota model — most commonly on Corolla. This code means the heater built into your upstream oxygen (O2) sensor on Bank 1, Sensor 1 — the sensor before the catalytic converter — isn't behaving as the engine computer expects. Modern O2 sensors have an internal heating element so they reach operating temperature quickly and can read the exhaust's oxygen content right after startup. When the computer detects that the heater circuit is open, shorted, or drawing the wrong amount of current, it sets P0135. A cold or slow-to-heat sensor delays accurate fuel mixture readings, which can hurt fuel economy and emissions. Typical repair costs on Toyota range from $90 to $320, depending on the specific model and root cause.
Common Causes of P0135
- •Failed O2 sensor heater element (most common)
- •Blown O2 sensor heater fuse
- •Corroded or loose O2 sensor connector
- •Damaged or melted wiring near the exhaust
- •Open or shorted heater control circuit
- •Poor ground or power supply to the sensor
- •Faulty PCM/ECM heater driver (rare)
P0135 on Toyota by Model
Toyota Corolla(1 issue)
- Upstream Air/Fuel Ratio Sensor Heater Circuit Failure (P0135)2003-2008
On 2003-2008 Corollas the upstream sensor (Bank 1 Sensor 1) is a heated wide-band air/fuel-ratio sensor mounted in the exhaust manifold ahead of the catalytic converter. Its internal heater element is a known wear-out item; when it fails, the ECM sets P0135 (O2/AF sensor heater circuit malfunction) and illuminates the check-engine light. Because the 1ZZ-FE is a single-bank engine, this always refers to the upstream manifold sensor. Symptoms are often minimal (longer time to reach closed-loop, occasional cold-start hesitation), but the MIL will fail emissions/state inspection. It is one of the most commonly reported CEL causes on this generation.
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View P0135 across all makes →Frequently Asked Questions
What does P0135 mean on Toyota?▼
P0135 stands for "O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)." This code means the heater built into your upstream oxygen (O2) sensor on Bank 1, Sensor 1 — the sensor before the catalytic converter — isn't behaving as the engine computer expects. Modern O2 sensors have an internal heating element so they reach operating temperature quickly and can read the exhaust's oxygen content right after startup. When the computer detects that the heater circuit is open, shorted, or drawing the wrong amount of current, it sets P0135. A cold or slow-to-heat sensor delays accurate fuel mixture readings, which can hurt fuel economy and emissions. On Toyota specifically, this code is documented across 1 model.
What causes P0135 on Toyota vehicles?▼
Common causes on Toyota: Failed O2 sensor heater element (most common), Blown O2 sensor heater fuse, Corroded or loose O2 sensor connector, Damaged or melted wiring near the exhaust, Open or shorted heater control circuit. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0135 on a Toyota?▼
Repair costs on Toyota range from $90 to $320, depending on the specific model and root cause.
Which Toyota models have P0135 documented?▼
Au7o has documented P0135 on 1 Toyota model: Corolla.