Check engine light comes on, gives codes 171 and 174

Top Five Reasons Your Check Engine Light May Be On

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AutoZoneYou may be wondering why your Check Engine Light is on. ... AutoZone is here to help with the top 5 reasons your Check Engine Light may come on. ... (hydrocarbons) from being released into the atmosphere while you aren't driving your car.

The Five Most Common Causes of a Check Engine Light ...

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LifehackerJan 24, 2012 - You're driving home from work one day when the car owner's worst nightmare happens: the check engine light pops on. It comes without ...

check engine light coming on usually sets a fault code, have the car scanned at reputable garage or some parts stores offer scanning codes for free and they will give you an idea of why light is coming on

Check engine light comes on and off, these are indication that there is some error code stored in your vehicles ECM. The engine module computer needs to be scanned. These will give the code and as per the error code the further problem can be detected and confirmed. The engine light indicator blinks or remains steady on dash when engine computer noticed any problem with any engine electrically operated components.

For more help, I suggest you to refer the help links provided below. These will let you know more about which areas to look, check, when there is engine light coming up on dash panel.

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Click the link below: -------

CHECK ENGINE LIGHT

http://alltypesofpartsreplacing.blogspot.com/2012/12/check-engine-lightengine-warning-light.html

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Check Engine Light Reset Procedure?
http://whoisbyme.blogspot.in/2012/06/check-engine-light-reset-procedure.html
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These will help.
Thanks.

Basically this means that an oxygen sensor in bank 2 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 2 is generally the side of the engine that doesn't have cylinder #1.
Note: This DTC is very similar to P0171, and in fact your vehicle may show both codes at the same time.
You will more than likely not notice any drivability problems, although there may be symptoms such as a lack of power, detonation (spark knock), and/or a hesitation/surge on acceleration.
The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.
I hope this helps.

The trac light comes on when ever the check engine light is on, the reason is that if the engine is not operating to 100% then the computer shuts down the trac as it can not operate correctly if something is wrong with the engine. the first step is to find out why the check engine light is on. the computer stores codes to help locate the problem, you will need to go to an auto parts store as many of them will scan the computer free of charge and give you the codes. the codes will be in the form of letters and numbers, if you can give me the codes i can help. for example the code would be like po306 cylinder 6 misfire. also when you write back codes re-enter year make and model with engine size. good day.

The codes you show are all about air leaks. The 507 is about the IAC and may simply be the system noting the connection was unplugged.

The 171,174 are lean codes and usually mean more air is coming in than is needed. Did you use a water mist to check for leaks? Have you checked Vacuum solenoids for leaks?, the EGR diaphram?

You did not indicate the engine and vehicle this problem was on. Some of the 6 cylinder products had sandwich type manifolds and the upper and lower chambers had a gasket which would dissolve and leak internally.

Some people have had problems with the runners on dual plane manifolds, but I question whether a 171, or 174 could generate from this defect.

I think you should retest with a water spray after clearing the computer.

The check engine light can come on for over 150 things, from a sensor to a loose gas cap, you will need to have the codes scanned, the computer stores codes when it detects something not working correctly,there are many auto part stores that will scan it for free and give you a print out of the codes, if you can give me the codes i could help you find out why the engine light is on, good day.

There are many emission sensors in the car that will make the engine light come ON. Not to mention the big list of trouble codes for the engine light. The engine light code will give you a big clue of what's causing the accelerator pedal problem.


Best way to find out what's going on engine light is to have an auto-parts store hook up a engine code reader and tell you what the code means and the problem. Most auto-part store will do this for free.

O2 SENSORS ARE BAD MOST LIKELY I WOULD CHANGE THEM DISCONNECT THE BATTERY FOR 5 MIN. ( IF YOU DONT HAVE A SCANNER) THIS WILL RESET YOUR COMPUTER AND SHOULD MAKE THE SERVICE ENGINE LIGHT GO OUT.

The light is coming back on because the cars computer is detecting that there is still a problem after it's reset. You need to have the engine codes scanned to determine what the problem is and correct it so the light can be reset. Check your local auto parts store, most do free scans of engine codes and will give you the meaning of the codes and what to do to fix the problem. If you need further help, post the codes here and any other info regarding the problem. Good luck