• The 6 Leading Factors That Could Affect a Smog Test

The 6 Leading Factors That Could Affect a Smog Test

The 6 Leading Factors That Could Affect a Smog Test Image

Are you new to the term smog test or smog check? Then it is our primary responsibility to make you aware of it. As one of the leading smog test centers in California, we take the initiative to explain to you the necessity of smog check if you own any kind of vehicle as well as the crucial factors that may affect a smog test.

Significance of Smog Check

We find that for many car owners or other types of vehicle owners, a smog check may appear to be of a lesser priority compared to the wide range of other sundry maintenance prerequisites for proper maintenance of your vehicle. However, any smog check from us or other providers goes a long way to preserve the environment, ensuring that your car is safe for its occupants apart from surrounding drivers, which can uncover a plethora of issues with gas cap leaks, air filtration, oxygen sensor malfunctioning, etc.

You may be surprised to know that in California only, there is a daily target of 100 tons of smog emissions being removed via these inspections, which is meant to be supported through the annual model. 

Only a rigorous smog check can ensure that these issues are detected early by us and can be addressed before they become more hazardous. On top of the dangers, your fuel efficiency can be managed in smog to help the driver to get the optimum output for their vehicle regularly.  

So, smog checks from us are necessary not only to ensure the proper working condition of the car but to religiously follow environmental safety as well. 

Vehicles, the older models in particular, or ones that are left inactive, can potentially run into issues during smog check in Rancho Cucamonga and other locations due to the following factors: 

The Necessity for Repairs

It’ll be unwise to allow a vehicle requiring major auto repairs to be smog checked as it will fail the test. We strongly recommend that a vehicle must be repaired completely during smog service before bringing it in for a smog inspection..

Insufficient Engine Temperature

Optimum operating temperatures are crucial to clear the emission test. We suggest that a vehicle has to be driven for a minimum of 20 minutes before being taken in for a smog check. This provides the oil, coolant, and catalytic converter with adequate time to reach and maintain the temperature suggested by emission test standards.

Poor Oil Condition

According to our experience, the engine oil condition may prove to be fatal during a smog check if the oil hasn’t been changed for the last 5,000 miles. Irregular oil changes are bound to cause a high concentration of hydrocarbons and will surely fail the smog check. 

Status of the Check Engine Light (CEL)

An illuminated CEL will cause an automatic failure during the smog test. But according to California State Law, a switched-on CEL can’t be a reason for avoiding a smog check. Visit an authorized emission repairs shop like ours for free check engine light diagnosis so that they may apply a trouble code retrieval tool to extract trouble code data from the ECU (Engine Control Unit) and perform necessary repairs, switching off the CEL.

Latest Battery Change or Disconnection

Due to a replacement of the existing battery or due to disconnection, the data related to the ‘Driving Cycle’ of a car will most probably be lost. We have observed that due to the lack of internal self-test monitors, a smog check can never be cleared. To do so, drive for nearly 100-200 miles for a week to reset or finish the emission monitors before getting smog inspected. 

Insufficient Tire Pressure

We are surprised that many car owners don’t know that all vehicle models older than 1999 are tested on a dynamometer during smog checks. Only adequate tire pressure, as necessary by the vehicle manufacturer, will confirm more stability and control while driving during the emission test. So, you must ensure that your tires are properly inflated before pulling in for a smog check. 


We suggest you confirm through smog service in Rancho Cucamonga that all key performance indicators (KPI) of your vehicle are impressive enough to pass a smog test from us. It feels bad when we find someone failing the smog test. 

You may also visit us for instant DMV registration and tags as well as a change of ownership. We will be more than happy to help you.