1997 Nissan Pathfinder won’t pass smog check

I have replaced parts but still can't get my Pathfinder to pass a smog check.
Experienced mechanics share their insights in answering this question :
If the vehicle has a Check Engine light, this may be able to help diagnose the issue because it would produce a trouble code for the emissions system. If the vehicle does not have the Check Engine light illuminated, I would recommend having all the vacuum lines, exhaust system, and any emissions related engine parts for cracks, leaks, or inoperative behavior by a technician with experience in emissions diagnosis. This symptom will almost certainly be associated with a Check Engine light so I would recommend starting there.

How to Identify and Fix Common car Problems ?

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If your car fails the smog inspection, you should contact the Bureau of Automotive Repair (BAR) Referee Program. They can help you find out what your next steps are.
start the vehicle and let it idle for two to three minutes in park or neutral. while it is idling, turn on the head lights, heater/defroster, and rear defroster for a three to five minute warm-up phase. let the idle speed settle down to near the normal speed.
A vehicle will not pass an emissions test when the check engine light is on. If the battery has been disconnected or the trouble codes erased, you will have to drive the vehicle under varying conditions for up to one week before it will pass.
Take your emissions test again after the scanner reads clear. After a few days of driving, plug the OBD-II back into the port and run another scan. If the error codes disappear and everything is green, you`ve confirmed that the drive cycle is complete and your car will pass the emissions test.
All vehicles that are model-year 1975 and older do not require a Smog Check.
Gasoline Powered Vehicles:

2000 and newer model year vehicles will need all emission monitors in READY or COMPLETE status, with the exception of the EVAP monitor. An incomplete evaporative monitor will not cause a smog check failure.

So why is the light still on? Here`s something you probably don`t know: after clearing the car`s computer you will need to drive for about 50 to 100 miles. As you drive your car the computer will monitor all the sensors and register the results.
2) Turn Your Car On and Off

Another way to reset the check engine light code that Marshall drivers can try is to turn the car on for about a second and then turn it off. Doing this will cause most vehicles to reset the trouble codes and the check engine light will turn off.

A “not ready” result means your vehicle`s computer has not had a chance to check all of the parts of the emissions control system for problems – so it cannot determine if everything is working as designed. Until the vehicle is “ready” to complete the checks, the OBD inspection cannot complete.
If a problem or malfunction is detected, the OBD II system illuminates a warning light on the vehicle instrument panel to alert the driver. This warning light will typically display the phrase “Check Engine” or “Service Engine Soon,” and will often include an engine symbol.
The state of California has stringent laws around vehicle inspections. As the vehicle seller, you are legally required to provide the buyer with a valid smog certificate at the time of sale. The buyer should also be informed that the provided smog certification is only valid for 90 days after the date it is issued.
Eligible consumers may receive up to $1,200 in emissions-related repairs at a STAR test-and-repair station if their vehicle fails its biennial Smog Check inspection.
You may be eligible to register your vehicle without a smog certificate. Eligible low income vehicle owners may receive a one time two year extension to complete necessary emissions related repairs.
California law requires emission testing of most vehicles registered in the state. If your vehicle fails to pass its first smog check, there is no need for distress—each smog test you purchase includes a free 90-day retest of vehicle emissions to offer you a second opportunity to pass the required vehicle smog check.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

What would your advice be to a person who needs to get a smog check on their car to make sure it passes the smog check? 2005 Mitsubishi
ANSWER : Hi there – the most straightforward and least expensive approach to this problem is to simply take your vehicle in for testing 15-30 days prior to your "deadline" (birthday month?). Most states or metro areas allow a 30 day "repair period" if there is any problem, and re-testing is usually free. Obviously, the car must be in good running order before having it tested. If your Check Engine light is illuminated, or the car runs badly, there is an issue, and the car must be repaired as appropriate. Once inspected, the "pass" certificate is also good for some period of time (sometimes as long as a year) as well, so there is no penalty for checking your emissions early. If you pass, you’re good-to-go. If not, you have a period of time to get it repaired before your current certificate expires. Good luck!

1997 Nissan Pathfinder won’t pass smog check
ANSWER : If the vehicle has a Check Engine light, this may be able to help diagnose the issue because it would produce a trouble code for the emissions system. If the vehicle does not have the Check Engine light illuminated, I would recommend having all the vacuum lines, exhaust system, and any emissions related engine parts for cracks, leaks, or inoperative behavior by a technician with experience in emissions diagnosis. This symptom will almost certainly be associated with a Check Engine light so I would recommend starting there.

2009 Nissan Murano won’t pass smog check
ANSWER : The camshaft position error is a likely cause for the vehicle no-start situation. The engine computer reads and relies on camshaft and crankshaft angle readings for ignition timing. No angle reading, no spark and a fail-safe to prevent engine damage. This will likely illuminate the Service Engine Soon light not long before a failure. Have a trained mechanic, like the ones here at YourMechanic, inspect and adjust your camshaft’s position.

Vehicle having a hard time passing smog check.
ANSWER : The first thing to do would be to see what the failures are. The Check Engine light would have to be scanned to see why it is on and address the codes. Then once the light codes are fixed then the emissions can be checked again. I would recommend having a mechanic, like the certified ones at YourMechanic, come and check it out for you to see what is causing the problem.

Can’t pass smog check with Check Engine Light on
ANSWER : The most common reason for your Check Engine Light coming on is for random engine misfires. You may be having this problem, and may need to have the ignition diagnosed, to see what is causing the misfire. You may have a failure of your coils, or plugs. The Check Engine Light would need to be checked to see which codes are received, for a proper diagnosis.

2006 Ford Mustang has check engine light on
ANSWER : There are countless potential causes for your illuminated check engine light. The mechanic manually turned off the light, but it came back on because the problem has not been fixed. The first place to start is retrieval of the stored diagnostic trouble codes (DTCs). These codes serve as a starting point for any further diagnostics a mechanic may perform. Codes will be stored anytime the check engine light is on. Since the first mechanic was unable to fix your concern, I recommend giving the professionals at YourMechanic a call. We offer expert check engine light diagnosis and repair.

Car won’t pass smog check
ANSWER : Hi there. Your smog check is measured as to how efficiently your vehicle is burning fuel and air. Smog is reliant on many different components. Your EGR valve, vacuum, and also your catalytic converter are factored in. I would strongly recommend to have a mechanic, such as one from YourMechanic, precisely diagnose the problems your vehicle is experiencing with failing smog requirements.

Can’t pass smog check due to Check Engine light
ANSWER : The Check Engine light requires a special scan tool to determine the issue. Additional diagnostics may be required. An intake leak is common on this engine and may cause leaks, low fluids, and many other issues. With the vehicle sitting for a long time, other issues may be present. A qualified technician, such as one from YourMechanic, can assist you with diagnosis of your car’s Check Engine light.