P0136 on Toyota
O2 Sensor Circuit Malfunction (Bank 1, Sensor 2)
P0136 on Toyota vehicles indicates o2 sensor circuit malfunction (bank 1, sensor 2). Au7o has documented this code across 1 Toyota model — most commonly on Corolla. This code indicates a malfunction in the downstream oxygen sensor circuit for bank 1, sensor 2 — the O2 sensor located after the catalytic converter on the engine side containing cylinder 1. This rear sensor's main job is to monitor how well the catalytic converter is working by checking the oxygen content of the cleaned exhaust. The computer sets this code when the sensor's signal is out of range, implausible, stuck, or its circuit appears faulty. It generally points to the downstream sensor, its wiring or heater circuit, or an exhaust leak, rather than an immediate engine performance problem. Typical repair costs on Toyota range from $90 to $320, depending on the specific model and root cause.
Common Causes of P0136
- •Failed or aged downstream oxygen sensor
- •Damaged O2 sensor wiring, connector, or heater circuit
- •Exhaust leak near the rear sensor
- •Open or short in the sensor heater power supply
- •Corrosion or poor connection at the sensor connector
- •Contaminated sensor (oil, coolant, or fuel additives)
- •Faulty engine control module (rare)
P0136 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 P0136 across all makes →Frequently Asked Questions
What does P0136 mean on Toyota?▼
P0136 stands for "O2 Sensor Circuit Malfunction (Bank 1, Sensor 2)." This code indicates a malfunction in the downstream oxygen sensor circuit for bank 1, sensor 2 — the O2 sensor located after the catalytic converter on the engine side containing cylinder 1. This rear sensor's main job is to monitor how well the catalytic converter is working by checking the oxygen content of the cleaned exhaust. The computer sets this code when the sensor's signal is out of range, implausible, stuck, or its circuit appears faulty. It generally points to the downstream sensor, its wiring or heater circuit, or an exhaust leak, rather than an immediate engine performance problem. On Toyota specifically, this code is documented across 1 model.
What causes P0136 on Toyota vehicles?▼
Common causes on Toyota: Failed or aged downstream oxygen sensor, Damaged O2 sensor wiring, connector, or heater circuit, Exhaust leak near the rear sensor, Open or short in the sensor heater power supply, Corrosion or poor connection at the sensor connector. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0136 on a Toyota?▼
Repair costs on Toyota range from $90 to $320, depending on the specific model and root cause.
Which Toyota models have P0136 documented?▼
Au7o has documented P0136 on 1 Toyota model: Corolla.