1999 Mazda Protege Codes P0420 and P0106

Tiny
SEWARDTA
  • MEMBER
  • 1999 MAZDA PROTEGE
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 149,000 MILES
I bought this used 99 Mazda Protege about 2 weeks ago and two or three days ago my Check Engine Light came on. I have been researching and have seen what the problems could be. I went to Advanced Auto and got the computer diagnostics and it showed codes. P0420 and P0106. The first is about the catalyst in bank 1 and the second is saying something about the map sensor. I go to Virginia Tech in Blacksburg, VA and I have been driving this car around with no problems at all. I drove it from Richmond, VA to Blacksburg, VA (around 300 miles) and I had no problems at all even while climbing mountains. Could there be an easy way to fix these codes. Also, the dealer I bought it from said the car was under a stricter emissions law than what I need so could that be the problem? And if so is there something that I need to look into to get it fixed or is the temporary fix (unplugging the battery) good enough. Thanks.
Friday, January 9th, 2009 AT 12:01 PM

7 Replies

Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Those cars had big problems with the cat converters going bad, usually around 100k. Ifit had a cat efficiency code, then it will probably need to be replaced. If so go to Mazda and be a very squeeky wheel, let them know that you are aware of the issues with the cats on these cars. If they wont replace it ask for the area Mazda reps phone number
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Friday, January 9th, 2009 AT 12:14 PM
Tiny
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Will this also fix the P0106 code that deals with the MAP sensor or is that something else separate that needs to be looked into?
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Friday, January 9th, 2009 AT 12:41 PM
Tiny
2CARPRO JACK
  • MECHANIC
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Might not since your car sets the code, but runs ok. If it were plugged (cat) enough to kill the engine I would think it might set a MAP code, but that may be a completely different problem
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Friday, January 9th, 2009 AT 2:23 PM
Tiny
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So do you think the cat needs to be unplugged or do you think it needs to be replaced. I just want to make sure that is the problem because it isn't a cheap thing to do. Also, Recently one of my belts are making noise when it is cold outside (early in the morning). It only happens when it is cold and it happens when I brake and go to a stop or when I start driving from a complete stop. Does this mean that one of my belts are just loose? I looked at both belts and they don't appear to have any wear on them (both look brand new). Thanks.
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Saturday, January 10th, 2009 AT 2:49 PM
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
The P0106 is for the Baro sensor. This is effected by EGR system problems, which can stem from partially plugged or not efficient cats. The P0420 is a "catalyst effiency below limit" which usually points to a bad cat on those cars. At 149k you may have a little problem getting Mazda to stand behind it though.
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Saturday, January 10th, 2009 AT 4:14 PM
Tiny
TEDDY0682
  • MEMBER
  • 2 POSTS
I too had these codes. P0106 was cleared with the cleaning of the EGR ports. However, this will led to a new code: P0401 (low egr flow?). Turns out these cars have HORRIBLE EGR valves. They rust and stick open.

You are basically looking at having your EGR system and potentially Cat Conv changed out. I have 220k mi on my car and it runs GREAT! City mpg @ 29.

I'm just getting this (and timing belt) fixed to pass state inspection. =/ Currently in the shop.
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Tuesday, January 19th, 2010 AT 3:33 PM
Tiny
TEDDY0682
  • MEMBER
  • 2 POSTS
So my initial trip to the mechanic was for the following:
- Rough noise coming from Driver side wheel,
- whining belts,
- Engine light code P0106

Results from trip to Mechanic:
- Replaced Wheel bearing and inner seal bearing,
- replaced pwr steering and Alt belts
- cleaned EGR ports (resulted code P0401)
- replaced EGR valve (resulted code P0420)
- replaced Catalytic Converter (no engine light yet)
- replaced Timing Belt (includes belt, belt tensioner,
idler bearing, waterpump, seals and gaskets)

I replaced the Timing Belt bc the car has 220k miles and I dont think it had ever been done!
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Monday, January 25th, 2010 AT 7:55 AM

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