The majority of the early Honda Pilot emission system problems resulted from simple catalytic converter or oxygen sensor failures, as is the case with other cars.

Many of the second-generation Honda Pilot’s emission system problems are caused by its clever (yet problematic) cylinder-deactivation hardware, which was also installed in first-generation FWD Pilots starting in 2006.

This hardware allows the engine to shut down one bank of three cylinders when the vehicle is being driven lightly. The third-generation Honda Pilot has a special issue that is caused by its direct fuel injection system. However, as this model’s engines were improved over time, fascinating new failure modes were added to its emission control systems.

Honda Pilot Emission System Problem: What Does It Mean?

A Honda Pilot’s emissions system is designed to lessen the amount of dangerous pollutants that are released into the atmosphere. The emission of these pollutants, however, may increase if there is a problem with this system.
The onboard computer will record a fault whenever a significant issue with an engine’s emission control system arises.

Any Honda Pilot will also include an emissions system malfunction alert that will notify the driver that something is amiss by turning on a warning light in the instrument panel.

But those warning lights simply display obscure symbols; what does the illogically illuminated emissions-system light on a Honda Pilot even mean?

An onboard diagnostic (OBD-II) scan will be required to learn more about the precise issue at hand because a warning light could be activated for a variety of reasons.
While improvements like VCM (Variable Cylinder Control) and direct fuel injection increased the Honda Pilot’s engine’s efficiency, they also added more levels of complexity and presented more potential failure areas for the pollution control system.

Honda Pilot Emission System Problem: Causes

There are many things that can cause emissions problems in the Honda Pilot. Those things include the following:

Oxygen sensor malfunction

The oxygen content of the exhaust gas is being monitored by this sensor. It can increase the discharge of dangerous pollutants if it is not functioning correctly.

Leak in the Exhaust System

Leaks in the exhaust system can make it possible for poisonous gases to enter the car’s interior, endangering the occupants, as well as making it more difficult for the engine to operate efficiently, which raises emissions.

Catalytic Converter in fault

The catalytic converter transforms dangerous exhaust fumes into less toxic ones. Its malfunction could result in an increase in emissions.

Clogged Air Filter

The engine may run less effectively and emit more pollutants as a result of a clogged or dirty air filter that restricts the flow of air to it.

Honda Pilot Emission Problem: Fuel injector issue

A malfunctioning fuel injector could make the engine run lean, which would increase emissions.

Spark plugs can get clogged, and catalytic converters can become contaminated if the VCM system fails. Excessive oil usage might also result from this.

The second-generation models that underwent a facelift from 2012 to 2015 or those that did not from 2008 to 2011 could both experience this issue.

Direct fuel injection was added to the third-generation Pilot, adding the chance of fuel injector or high-pressure fuel pump (HPFP) failure to the mix of problems. Pilots from the 2016–2018 model years are the most likely to experience this issue.

The tight tolerances in the HPFP and injectors would be negatively impacted, hence, it is most likely caused by contamination of the fuel channels during production.

What to do when You notice Honda Pilot Emission System Problem

First and Second Generation Honda Pilots (2003–2015)

There’s a possibility that an emission system issue won’t immediately cause your first- or second-generation Honda Pilot to come to a complete stop. The only exception to this rule on these models is if the warning light also flashes and there is rattling coming from underneath the car, which could be a sign of a pre-catalyst that is disintegrating. If this happens, loose catalyst pieces could enter the combustion chambers through the exhaust ports and seriously harm the engine’s internals.

Third Generation Honda Pilot (2016–2019)

However, the third-generation Honda Pilot—specifically the 2016, 2017, 2018, and 2019 model years—is a different story because direct fuel injector issues with these models could result in a number of different issues in the cylinders.

It could result in a lean-running condition on one (or more) of the cylinders, which could harm the pistons or cylinder heads, or it could result in a rich-running condition and misfires, which would damage the cylinder bores and foul the spark plugs, which would damage catalytic converters.
In the short term, VCM (Variable Cylinder Control) issues are not as problematic; therefore, there should be ample time before their effects grow severe enough to result in secondary damage.

Keep in mind that this will still need to be fixed as soon as possible because every mile that passes increases the risk of poisoning the catalysts and hastening engine wear. Importantly, the primary failure mode of the VCM unit is oil leakage to the outside of the engine.

If this happens, hot oil may splash over the alternator, destroying this expensive part and resulting in a loss of oil pressure inside the engine, which may lead to damaged engine bearings and camshafts.

How to Fix Honda Pilot Emission System Problem

For the Honda Pilot, there is no one straightforward solution to the emission system issue. VCM issues and malfunctioning fuel injectors are probably beyond the capabilities of non-professional mechanics; however, other emission system defects are quite simple to fix for a moderately skilled home mechanic. The following measures can be used:

Examine the sensors and actuators.

If a sensor or actuator is to blame, the owner needs to purchase and replace it. The oxygen- and engine temperature sensors, for example, are relatively cheap and accessible, so if an OBD-II scan identifies one of these straightforward components as the source of an error code (such as P0420), nearly anyone can replace it. Just keep in mind that when you’re finished, you need to use the scanning equipment to reset the Honda Pilot emission check system alarm.

Look for wiring harness issues.

If a wiring harness problem is the cause of the faults, it will be difficult to track down the issues. The wire harnesses of the Honda Pilot use environmentally friendly soy-based insulation, and if rodents have eaten away at that delectable insulation, the scale of the repair makes it advisable to leave this operation to a specialist.

Check for VCM issues.

Simply because it’s exceedingly challenging to access the VCM unit on the rear cylinder head, VCM troubles are really outside the purview of home mechanics. The majority of the intake manifold needs to be taken apart in order to access the VCM unit, and even then, it’s not that simple. Leave this to the experts, please.

Check for fuel injector or HPFP failure

Honda has published several service bulletins for 2016–2018 Pilots that call for the replacement of the high-pressure fuel pumps and/or injectors for specific models in order to solve the potential fuel injector or high-pressure fuel pump (HPFP) issue on third-generation Honda Pilots.

The owner will be responsible for at least $500 in repair charges if the car is not still covered by the manufacturer’s warranty, as this is not a recall.

How to Avoid Honda Pilot Emission System Problem

There are so many things that you are expected to do as a car owner in order to avoid the Honda Pilot Emissions System problem.

Proper maintenance of the vehicle:

This entails routinely checking and replacing your oil, as well as carrying out other standard maintenance procedures.

Be mindful of any potential issues or symptoms

Have your vehicle checked by a professional whenever you notice any problems.

High-quality Fuel should be used, and don’t top off your tank

This should be done in order not to contaminate the emission system.


The Honda Pilot’s malfunctioning emissions system is a red flag for a pollution control system issue. There are several potential causes for this, from a straightforward problem like a filthy air filter to a more significant issue like a malfunctioning oxygen sensor.

It’s crucial to take your car to a trained mechanic if you’re having this issue so they can identify and resolve the problem. If not, you run the danger of damaging your engine or causing other problems in the future.

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