Understanding The Top 10 Honda Fit Diagnostic Trouble Codes
Explore the common DTCs that can affect Honda Fit engines, and learn about their potential causes, symptoms, and location. Our comprehensive engine maintenance guides can assist with diagnosis and repairs to keep your vehicle running smoothly
TOP 10 DTCS
DTC P0420 – Catalyst System Efficiency Below Threshold (Bank 1)
DESCRIPTION: The catalytic converter is not functioning properly, and the emissions are exceeding the maximum allowed by the engine control module (ECM).
CAUSE: The cause of this code can be due to a faulty catalytic converter, faulty oxygen sensors, exhaust leaks, or other issues with the exhaust system.
SYMPTOMS: The most common symptom of this code is the illumination of the check engine light. There may not be any other noticeable symptoms, but the vehicle may not pass emissions tests.
LOCATION OF FAULT: Bank 1 refers to the side of the engine where cylinder number 1 is located. The catalytic converter on this side of the engine is likely to be the one causing the issue.
DTC P0301 – Cylinder 1 Misfire Detected
DESCRIPTION: The ECM has detected a misfire in cylinder number 1, meaning that the fuel and air mixture is not being ignited properly in this cylinder.
CAUSE: This code can be caused by a variety of issues, such as faulty spark plugs, ignition coils, fuel injectors, or even low compression in the cylinder.
SYMPTOMS: The vehicle may run rough or have a noticeable decrease in power when this code is present. The check engine light will also illuminate.
LOCATION OF FAULT: The fault is specifically in cylinder number 1, which is located on the front, driver’s side of the engine.
DTC P0300 – Random/Multiple Cylinder Misfire Detected
DESCRIPTION: Similar to P0301, this code indicates that there is a misfire occurring in multiple cylinders, or the ECM is unable to determine which cylinder is misfiring.
CAUSE: The causes for this code can be similar to those for P0301, but there may be multiple issues causing the misfires.
SYMPTOMS: The symptoms for this code can include rough running, loss of power, and a flashing check engine light.
LOCATION OF FAULT: The fault can be in any of the cylinders, so it is important to further diagnose the specific cause.
DTC P0171 – System Too Lean (Bank 1)
DESCRIPTION: The air-to-fuel ratio in the engine is too lean, meaning that there is too much air or not enough fuel in the mixture.
CAUSE: This code can be caused by a variety of issues, such as a faulty oxygen sensor, vacuum leaks, or a malfunctioning fuel injector.
SYMPTOMS: The most common symptom for this code is a hesitation or lack of power during acceleration, along with the check engine light illuminating.
LOCATION OF FAULT: Bank 1 refers to the side of the engine where cylinder number 1 is located, so the issue is likely to be on this side of the engine.
DTC P0134 – O2 Sensor Circuit No Activity Detected (Bank 1, Sensor 1)
DESCRIPTION: The ECM is not detecting any activity from the oxygen sensor located before the catalytic converter on Bank 1.
CAUSE: The cause of this code can be a faulty oxygen sensor, damaged wiring or connections, or a failed ECM.
SYMPTOMS: The most common symptom for this code is the illumination of the check engine light.
LOCATION OF FAULT: Bank 1 refers to the side of the engine where cylinder number 1 is located, and Sensor 1 refers to the oxygen sensor located before the catalytic converter on this side of the engine.
DTC P0135 – O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
DESCRIPTION: The ECM is detecting a malfunction in the heater circuit for the oxygen sensor located before the catalytic converter on Bank 1.
CAUSE: The cause of this code can be a faulty oxygen sensor heater, damaged wiring or connections, or a failed ECM.
SYMPTOMS: The most common symptom for this code is the illumination of the check engine light. There may not be any other noticeable symptoms.
LOCATION OF FAULT: Bank 1 refers to the side of the engine where cylinder number 1 is located, and Sensor 1 refers to the oxygen sensor located before the catalytic converter on this side of the engine.
DTC P2646 – Rocker Arm Actuator System Performance/Stuck Off (Bank 1)
DESCRIPTION: This code indicates an issue with the rocker arm actuator system on Bank 1, which helps control the valves in the engine.
CAUSE: The cause of this code can be a malfunctioning actuator, damaged wiring or connections, or a failed ECM.
SYMPTOMS: The most common symptom for this code is a rough idle or loss of power, along with the check engine light illuminating.
LOCATION OF FAULT: Bank 1 refers to the side of the engine where cylinder number 1 is located, so the issue is likely to be on this side of the engine.
DTC P0507 – Idle Air Control System RPM Higher Than Expected
DESCRIPTION: This code indicates that the idle air control system is not functioning properly, resulting in a higher-than-expected engine speed at idle.
CAUSE: The cause of this code can be a malfunctioning idle air control valve, a vacuum leak, or issues with the throttle body.
SYMPTOMS: The most common symptom for this code is a high idle speed, along with the check engine light illuminating.
LOCATION OF FAULT: The fault is likely to be in the idle air control valve or the throttle body.
DTC P0455 – Evaporative Emission Control System Leak Detected (Large Leak)
DESCRIPTION: The ECM is detecting a large leak in the evaporative emission control system, which helps control the release of fuel vapors into the atmosphere.
CAUSE: The cause of this code can be a faulty gas cap, damaged hoses, or a malfunctioning purge valve.
SYMPTOMS: The most common symptom for this code is the illumination of the check engine light. There may not be any other noticeable symptoms.
LOCATION OF FAULT: The location of the leak can be anywhere in the evaporative emission control system, so further diagnosis is necessary to determine the exact location.
DTC P0128 – Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
DESCRIPTION: This code indicates that the engine is not reaching the proper operating temperature, which can affect fuel economy and emissions.
CAUSE: The cause of this code can be a faulty thermostat, a low coolant level, or issues with the coolant temperature sensor.
SYMPTOMS: The most common symptom for this code is a decrease in fuel economy, along with the check engine light illuminating.
LOCATION OF FAULT: The fault is likely to be in the thermostat or the coolant temperature sensor.
WORDS FROM ME
Discover the common DTCs that can affect Honda Fit engines, and learn about their potential causes, symptoms, and location. At our site, we understand the importance of maintaining your vehicle’s engine, and we are dedicated to providing you with the information you need to keep your Honda Fit in top condition.