Question about 2000 Mazda Protege

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Check engine light won't go away

Car with check engine light on. Diagnosis cat not up to par. replaced cat and ox sensor. check engine light back on. Now running rough at idle. Diagnosis now is egr valve, noticed low vacume. Any thaughts?

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  • redlining Sep 24, 2008

    I didn't replace my cat yet, on my 2002 Protege ES (the car has 121K Miles on it) but I took it to auto zone and they pulled a P0401 code. Likely causes are the EGR Valve. I plan to buy a rebuilt one on ebay for $40 instead of paying Autozone or the dealer $150-$170 for a new one. It was running ridiculously rough when I came to a stop but only intermittently. (Maybe every 8th stop or so). I could also feel a bit of a ping during highway driving.



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  • 9 Answers

I read it could be the mass air flow sensor and or faulty spark plugs. also be sure to check all the little vaccum hoses for cracks.

Posted on Sep 20, 2008


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No power/acceleration + shaking left exauhst

Which solenoid was replaced? Why wasn't the correct oil in there the first time? Secondary O2 sensors only monitor cat. Converter efficiency. NGK uranium sounds fancy and I'm sure the parts guy thought so too but is that recommended by GM? What was the check engine light on prior to all of this? If you had a p0420 suspect a melted cat. Converter. Fire it up and hit cat with hammer. Might fix it but that check engine light will be right back. Easy diagnosis though

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1 Answer

Had 3 codes come up for ox. sensor..po155-po151-po153 which one to replace and exactly where located?

it is the o2 sensor in front of the cat converter jack up truck and support under truck locate ur cat converter do this with truck cold cat can burn skin very easily same with exhaust pipes .when locate converter follow pipe forward towards engine look toward top of exhaust pipe will see a small tube with wire connected this is problem sensor check wiring and connector un plug and remove replace than reconnect

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I am hoping someone on here can help me with my problem...My check engine light came on my 2003 Chrysler 300 M special edition and also wouldn't start at times for up to 30-45 minutes at a time, and...

Have you had the battery changed since you had the car. Have that checked for a full charge and no dead cells. Always have the air-conditioning completely off when starting the car. The starter takes a lot of amps to turn over and having the AC on doesn't help.

and another reason is the code didn't clear out completely. this tool can help you test the code.

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I have an audi 3.0l 2002 audi a4 avant quattro. I printed out a paper stating i could reset my oxygen sensor warning light ( check engine light ). I have torn my car apart looking for the letters oxs near...

The dealer has to "reflash" your 02 sensor light. On some Audi's, the dealer has to reset the O2 code first and if it comes on again, then they will need to replace the cat convertors.

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I have a 1996 saturn wagon. it failed on omissions for egr. ox sensor and catalyst. I had a new egr.. o2 sensor.. oxygen sesor before catalyst.. drove car on many different drive cycles and over 4-600...

You need to read the codes that your check engine light is showing. Go to Autozone or any place like that and they can read the codes for free. Throwing parts at a car doesn't fix it but finding the source of the problem and then repairing as necessary will allow for better results. Going off the check engine light being on can mean it is anything.

You have two O2 sensors on your car. One just after the head on the header. This is the O2 sensor that tells the PCM what the air/fuel is and the PCM can adjust accordingly. The one BEHIND the catalytic converter (or cat for short) does nothing but tell the PCM that the cat. is working properly. You may be changing the wrong O2 sensor. Also the EGR could be an electrical problem if that is the cause of the emissions failure.

So to review, find out the codes, post back with the codes and everything can go from there.

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I recently could not get my car inspected in NY because of a Check Engine Light. I found that is was my O2 sensor. so I replaced all 4 of them. Now the light is back on and I had it checked says sensor 1...

The wiring to the sensor or the connection plug is burnt as the wiring gets close to the exhaust manifold and down pipe. Sensor 1 Bank 2 should be the right rear sensor or the back side of the engine after the cat. Check your wiring at the sensor plug and retrace back up to the the main harness to find a burnt spot or a break in the wire at a tie off to the frame. Next the vacuum leak may be a bad gas cap. Check to be sure it is on right, ck for any hoses that may have be loosened during the replacement of the Ox sensors.

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sorry dealer only ,this information is not published ,go to dealer and lay the golden egg ----owing to complexity of the anti-theft systems and not allowing this information for general use to stop car theft ??well thats the excuse anyway .do you know a good solicitor who can sue them under the freedom of information act you have stateside .because in europe the problem is acute with no re -address.. .software encrypted so if you try to read it it just show anything with a general mechanics reader .are you preparing the golden egg ??ready for the dealer ??my advice if it runs ok leave well alone and throw you scan master or digisoft reader in the bin as it will not work on modern cars and the newer the car the less you can do with it.

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