The MOST Common 15 OBD DTC of Toyota Cars
The MOST Common 15 OBD DTC of Toyota Cars . The onboard diagnostic system (OBD) is an essential part of modern vehicles, including Toyota cars. It monitors various vehicle systems and components and reports any issues through diagnostic trouble codes (DTCs). These codes help technicians diagnose and fix problems with the vehicle quickly and efficiently.
In this context, we will discuss the 15 most common OBD DTCs found in Toyota cars. These codes cover a range of issues, from engine misfires to problems with the emission control system. Understanding these codes and their causes can help Toyota car owners identify and address potential problems before they become more severe.
COMMON DTC OF TOYOTA CARS
DTC P0300 – Random/Multiple Cylinder Misfire Detected
Description: This DTC indicates that multiple cylinders are misfiring randomly.
Cause: The cause of this DTC can be a variety of issues such as a faulty ignition coil, spark plugs, fuel injectors, or a clogged fuel filter.
Fix: Diagnose and repair the root cause of the misfire. Replace any faulty components such as spark plugs or fuel injectors.
DTC P0420 – Catalyst System Efficiency Below Threshold
Description: This DTC indicates that the catalytic converter is not functioning properly and is not converting emissions effectively.
Cause: The cause of this DTC can be a failing catalytic converter, a damaged O2 sensor, or a vacuum leak.
Fix: Replace the faulty catalytic converter or O2 sensor. Fix any vacuum leaks.
DTC P0440 – Evaporative Emission Control System Malfunction
Description: This DTC indicates that there is a problem with the evaporative emission control system.
Cause: The cause of this DTC can be a faulty fuel cap, a leak in the fuel tank or fuel lines, or a faulty charcoal canister.
Fix: Check the fuel cap for damage or looseness. Replace any damaged fuel lines or the charcoal canister if necessary.
DTC P0171 – System Too Lean (Bank 1)
Description: This DTC indicates that there is not enough fuel in the air-fuel mixture for cylinder bank 1.
Cause: The cause of this DTC can be a vacuum leak, faulty O2 sensor, or a clogged fuel filter.
Fix: Locate and repair any vacuum leaks. Replace any faulty O2 sensors or fuel filters.
DTC P0172 – System Too Rich (Bank 1)
Description: This DTC indicates that there is too much fuel in the air-fuel mixture for cylinder bank 1.
Cause: The cause of this DTC can be a faulty O2 sensor, a clogged air filter, or a fuel pressure regulator problem.
Fix: Replace any faulty O2 sensors or the fuel pressure regulator. Replace the air filter if necessary.
DTC P0128 – Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
Description: This DTC indicates that the engine is not reaching the proper operating temperature.
Cause: The cause of this DTC can be a faulty thermostat or a low coolant level.
Fix: Replace the faulty thermostat or refill the coolant to the proper level.
DTC P0446 – Evaporative Emission Control System Vent Control Circuit Malfunction
Description: This DTC indicates that there is a problem with the vent control circuit in the evaporative emission control system.
Cause: The cause of this DTC can be a faulty vent valve, a damaged or disconnected vacuum hose, or a faulty pressure sensor.
Fix: Replace the faulty vent valve or pressure sensor. Check for damaged or disconnected vacuum hoses.
DTC P0301 – Cylinder 1 Misfire Detected
Description: This DTC indicates that there is a misfire in cylinder 1.
Cause: The cause of this DTC can be a faulty spark plug, ignition coil, or fuel injector.
Fix: Replace any faulty components such as spark plugs or ignition coils.
DTC P0304 – Cylinder 4 Misfire Detected
Description: This DTC indicates that there is a misfire in cylinder 4.
Cause: The cause of this DTC can be a faulty spark plug, ignition coil, or fuel injector.
Fix: Replace any faulty components such as spark plugs or ignition coils.
DTC P0302 -Cylinder 2 Misfire Detected
Description: This DTC indicates that there is a misfire in cylinder 2.
Cause: The cause of this DTC can be a faulty spark plug, ignition coil, or fuel injector.
Fix: Replace any faulty components such as spark plugs or ignition coils.
DTC P0303 – Cylinder 3 Misfire Detected
Description: This DTC indicates that there is a misfire in cylinder 3.
Cause: The cause of this DTC can be a faulty spark plug, ignition coil, or fuel injector.
Fix: Replace any faulty components such as spark plugs or ignition coils.
DTC P0421 – Warm Up Catalyst Efficiency Below Threshold (Bank 1)
Description: This DTC indicates that the warm-up catalyst is not functioning properly for cylinder bank 1.
Cause: The cause of this DTC can be a failing catalytic converter, a damaged O2 sensor, or a vacuum leak.
Fix: Replace the faulty catalytic converter or O2 sensor. Fix any vacuum leaks.
DTC P0136 – O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)
Description: This DTC indicates that there is a problem with the O2 sensor circuit for cylinder bank 1, sensor 2.
Cause: The cause of this DTC can be a faulty O2 sensor, a wiring issue, or a failed catalytic converter.
Fix: Replace the faulty O2 sensor or repair any wiring issues. If the catalytic converter fails, replace it.
DTC P0441 – Evaporative Emission Control System Incorrect Purge Flow
Description: This DTC indicates that there is a problem with the purge flow in the evaporative emission control system.
Cause: The cause of this DTC can be a faulty purge valve, a vacuum leak, or a damaged canister.
Fix: Replace the faulty purge valve or canister if necessary. Check for any vacuum leaks and repair them.
DTC P0500 – Vehicle Speed Sensor Malfunction
Description: This DTC indicates that there is a problem with the vehicle’s speed sensor.
Cause: The cause of this DTC can be a faulty vehicle speed sensor or wiring issue.
Fix: Replace the faulty vehicle speed sensor or repair any wiring issues.
By understanding these 15 common DTCs, Toyota car owners can stay on top of their vehicle’s maintenance and avoid potential breakdowns or other issues. Regular maintenance and prompt attention to any warning lights or unusual behaviors can help ensure the longevity and reliability of Toyota cars.
Researched and compiled by Erwin C. Salarda