By in Business

Cheat emissions test pass smog P0420 P0430 Catayltic converter

Many people are desperate to keep their cars on the road with limited funds for repairs. In the USA many states have tough pollution laws that require drivers to spend thousands of dollars on emissions repairs or lose the ability to drive that car legally. Of course if you have the cash go ahead and fix your car properly you cheapskate.

If you are mechanically savvy and desperate for some money-saving ideas then read on. The following information is for educational purposes only. You should never tamper with a car without proper training and tools.

Most older cars (pre-1996) that fail for CO need a new oxygen sensor.

Older cars with high NOX reading may have timing set too advanced, a malfunctioning EGR system or an empty catalytic converter. Overheating will also cause a high NOX reading.

P0171 P0174 Fuel system lean. Air leaks (vacuum leaks) and mass air flow sensors. Using a scan tool and some metallic tape you can block off some of the void space on the inlet side of the mass air flow sensor to increase the sensors air volume reading. With a little practice you can get the fuel trim numbers just right and eliminate these fault codes.

P0401 Toyota: If all the EGR components test okay replace the vacuum switching valve.

P0128 Honda Civic Radiator temperature sensor.

P0420 P0430 catalytic converter. Pack rear oxygen sensors (behind converter) with RTV, silicone gasket maker. Clear codes and drive on the highway. If this makes the car run funny then replace the rear sensors after passing the emissions test. Never do this to a front oxygen sensor before the converter. Another method on cars with two rear oxygen sensors is to connect the two rear signal wires together. The averaging of the voltage can sometimes make it pass. Wiring diagram needed.

Some faults do not need to be repaired like evap problems in order to pass the test. A mechanic can perform the drive cycle with scan tool and test the car at the right moment before the fault appears.

Image Credit »

You will need an account to comment - feel free to register or login.


Ellis wrote on October 2, 2014, 11:52 AM

I take it the car in the picture didn't

Scorpie wrote on October 2, 2014, 11:53 AM

Har! No, she's toast.

Kasman wrote on October 2, 2014, 11:59 AM

Pardon me but is some of this not cheating? If an owner can't afford to get the repairs done properly then they should obey the law and stop using the vehicle.

Scorpie wrote on October 2, 2014, 1:41 PM

True in a perfect world but we are light years from that.

BarbRad wrote on October 2, 2014, 2:27 PM

Ethics question: What kind of world do we live in where it's OK to cheat on your wife but not on your smog test?

AliCanary wrote on October 2, 2014, 10:32 PM

The first car my husband and I ever bought, when we were young and clueless, was a Toyota Camry from which someone had REMOVED the catalytic converter. Needless to say, it didn't pass the emissions inspection. It was quite a chunk of change to get that damn thing replaced, but it turned out to be a really good car for us, so I can't wail too much. It had 187,000 miles on it when we finally traded it in.

Scorpie wrote on October 2, 2014, 10:36 PM

Camry is still the king of high-value cars. My wife has one with leather.

Scorpie wrote on October 2, 2014, 10:41 PM

It's okay to cheat on your wife?

BarbRad wrote on October 2, 2014, 10:46 PM

I didn't say it was. Just implied that some people who would might make a big deal about cheating on a smog test.

Scorpie wrote on October 2, 2014, 10:49 PM

In car dependent economies I think it's okay to use dirty tricks to help poor people pass smog. Poor people have the highest repair expenses because their cars are generally older.

LoudMan wrote on October 3, 2014, 9:01 AM

Don't get caught. Depending on the state, they can be terrible about it.

Scorpie wrote on October 3, 2014, 9:25 AM

Most tamper laws are geared toward licensed facilities, not car owners. As the owner of the car you can do pretty much anything to it as long as the final result is pass.

oldies909 wrote on October 6, 2014, 2:24 AM

Interesting article enjoyed reading it.

Bethany1202 wrote on October 7, 2014, 1:37 PM

We had emissions tests when I lived in Maryland, but here in West Virginia we need a yearly "inspection," which is a joke if you ask me. : /