Toyota Error Codes

System Too Lean (Bank 1) — very common on Toyota 4-cylinder and V6 engines.

Random/Multiple Cylinder Misfire — engine misfiring on multiple cylinders.

Catalyst System Efficiency Below Threshold (Bank 1) — catalytic converter degraded.

Idle Control System Malfunction — idle speed is erratic or not controlled correctly.

Small Evaporative Emission Leak — small EVAP leak detected.

Random/multiple cylinder misfire detected — the engine is misfiring on multiple cylinders or randomly.

Catalyst system efficiency below threshold (Bank 1) — catalytic converter is not cleaning exhaust properly.

Coolant temperature below thermostat regulating temperature — engine is running cold.

Mass Airflow (MAF) Sensor Circuit Range/Performance — the MAF sensor is reading but its value is outside the expected range.

Engine Coolant Temperature Sensor Circuit Malfunction — the coolant temp sensor circuit has faulted.

O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2) — the heater element in the downstream O2 sensor has failed.

Injector Circuit / Open — Cylinder 1 — the fuel injector circuit for cylinder 1 has an open circuit.

Knock Sensor 1 Circuit Malfunction (Bank 1) — the sensor detecting engine knock/detonation has a circuit fault.

Evaporative Emission System Malfunction — a general EVAP system fault has been detected.

Cylinder 4 Misfire Detected — cylinder 4 is not firing consistently.

Right Front Wheel Speed Sensor Circuit — the ABS module is not receiving a valid signal from the right front wheel speed sensor.

Driver Airbag Squib Circuit — a fault has been detected in the driver airbag deployment circuit.

Air-Fuel Ratio Sensor Response — Bank 1 Sensor 1 Malfunction (Toyota-specific) — the upstream A/F sensor is not responding correctly.

Cooling Fan 1 Control Circuit Malfunction — the primary cooling fan relay or circuit has a fault.