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Can I Ignore This Error Code (97 Mazda 626 Filter)
April 6, 2014 6:49 AM   Subscribe

The car my son drives (97 Mazda 626 with the 6 cylinder engine) is throwing a P1195 OBDII code. That is a error reading from the EGR sensor, but there are a variety of things that could cause that, and Google didn't turn up any advice about whether or not that is really a critical issue to deal with.

He said it was idling rough, but it was fine when I checked it yesterday. The car has 196,000 miles on the original engine and transmission, and I bought it in 2000. His sister is headed out of state to college in August and my goal with the Mazda is to get it through the summer because I think I'm going to get rid of it then as we'll have an extra vehicle while my daughter is away at school.

Of the most likely causes (bad sensor, clogged intake port, carbon build up) none of them seem to me to be things that are likely to strand my son on the side of the road with a dead vehicle. If I'm wrong about that please correct me. Also, emissions inspections are not an issue where I live.

What's the worst case scenario involving this code? The only other current ODBII code on the car is P0147 (I think.) It's an O2 sensor on the exhaust which has never had any impact that I can see on the operation of the vehicle. That code has been on for several years.

(Possibly related - he had a blinking CEL last week indicating a misfire on cylinder 4. The plug wires looked fine, so I replaced that spark plug and the code cleared and it's been fine since.)
posted by COD to Travel & Transportation (8 answers total)
 
It probably won't strand him, but I'd look into replacing the EGR and cleaning out the port/runner while you're in there. A car running like shit really is stressful to drive.

Also, it's possible the malfunctioning O2 sensor lead to more soot/carbon buildup in the exhaust, clogging the EGR. Depending on the application, they can sometimes be really cheap, and if you spray some PB (bolt loosener) on it a couple cycles before you remove it (so the heat+PB can work), it's likely to be a quick replacement.
posted by notsnot at 7:13 AM on April 6


whether or not that is really a critical issue to deal with.

Firmly in my 'don't give a crap' set of codes. Same as the Lambda sensor code. Worst case scenario is emissions, not not-running/breaking down.

Incidentally: Plug wires go bad long before they look bad, just so you know. They break down internally before the outside/ends look crappy. If the spark plug came out looking ok, it is likely that disturbing the wire helped it. I'd replace the wires and plugs as a set, never one at a time. Not worth the risk. The rough idle is more likely a result of old wires and plugs than the codes you mention.
posted by Brockles at 7:23 AM on April 6 [2 favorites]


I just had this problem with my 2002 Mitsubishi Galant.

My problem started with a low gas tank in the dead of winter, and my last fill-up was from a pump that kept stopping due to the gas stations's underground tank being almost empty. That's never a good thing - dirty fuel is nothing but trouble, especially when you have a low gas tank.

I had a terrible time starting it, and when I brought a can of gas back to fill it up more the next day, I finally got it running, and had a misfire error. The misfire error disappeared after a few days of sitting, and then I had new 02 sensor errors. Idling at stoplights was problematic, fuel efficiency was bad, and it just didn't sound right.

I ignored it for a month, then finally get the sensors check out. Mine has three sensors, and only two of them needed replacing: the exhaust and one of the engine O2 sensors (it happened to be the one that was handling the misfiring cylinder) The computer is going to compensate for the bad info its getting from the sensor, and after a while it's going to cause more issues. The computer will only work for with the information that it gets from the sensors, so eventually if the sensors give it bad information long enough, it's going to be mixing the fuel and air badly, and you're gonna have a bad time one day.

A good mechanic will be able to test all the 02 sensors to see which one is really the bad one, so you really only are going to replace the ones you need to.

It's also a good thing to teach your kids that in general, the "check engine" lights and error codes shouldn't be ignored, but not freaked out about. I've had friends that flat out ignore them, and others that immediately stop the car and refuse to drive it due to the check engine light being on - both of them learned this from how their parents reacted to these kinds of problems. How they will deal with car issues in the future is determined by how they see you handle it.

To sum this up: you have time, but you should get it checked out soon, and you don't have to fix all the problems at once.
posted by chambers at 10:32 AM on April 7


I just had this problem with my 2002 Mitsubishi Galant.

To clarify, no you didn't have this problem. I know you're trying to help, but there is no evidence your problem is even slightly related unless the OP also filled up with suspect fuel (and it sounds like they didn't). You had a 'related' problem only in that a check engine light, a sensor code and a misfire were involved.

This is why anecdotal advice is not useful - the three issues/results/symptoms that you identified as making your experience relevant are some of the basic symptoms of any number of faults. You can't extrapolate backwards from (what amounts to) very common symptoms to assess a level of severity based on your particular outcome.

The computer will only work for with the information that it gets from the sensors, so eventually if the sensors give it bad information long enough, it's going to be mixing the fuel and air badly, and you're gonna have a bad time one day.

This is bad information and factually inaccurate. If the sensor feedback is outside pre-set parameters, the ECU will ignore it as a faulty sensor and resort to a map of pre-determined readings. Your car will continue to run, albeit not as efficiently as it was, but certainly not in a way that will damage itself. These maps tend to the safer side of the options (running rich) which will most likely just make the car to use more fuel. There is no real evidence that 'you're going to have a bad time one day' will result from this. Cars that run rich can run rich for a very, very long time - almost indefinitely unless a different problem comes along. In the absence of emissions regulations this only has a slight effect on the wallet from the fuel bill. The car is not likely to fail.
posted by Brockles at 11:37 AM on April 7


I'm not implying my problem is the same as his problem, I was referencing my experiences to make a point about getting at least a checkup. There's nothing wrong with getting it looked at by someone you can reasonably trust, but there's also no obligation to actually do anything once you have the diagnosis. I should have edited that more.

I had been told of the long term problems that can arise from ignoring bad sensors from a few mechanics some of which is my father, but I see now they were probably being far too overcautious and not giving me accurate information about the more modern (i.e post-1980s) computer systems.

I'll stick by my statement about kids learning how to react to car troubles from their parents, though.
posted by chambers at 12:00 PM on April 7


I had been told of the long term problems that can arise from ignoring bad sensors from a few mechanics... probably being overcautious...

It does depend on the sensor - but you can ignore Lambda (O2) and EGR sensors all day long on pre-2000 (or thereabouts) cars if you don't need your catalytic converter to pass emissions....

I'll stick by my statement about kids learning how to react to car troubles from their parents, though.

Absolutely true. People either 'learn' or assume that CEL's are either pointless lights you can ignore (because they heard of one incident where they tightened the fuel cap and it went away) or they assume it means the engine will fall out. The sooner this is dispelled the better, so I completely agree with you there. Getting the general public to understand that the CEL is a nuanced means of communication (not just a yellow light) that should trigger reading the fault codes before deciding whether to ignore or not is a serious issue. I have a Metatalk thread from a while ago borne of exasperation from people seeing a CEL as a binary indicator or something interpreted without any further investigation. Trying to diagnose askme threads using the CEL as a 'symptom' is also a pet peeve of mine. You may have inadvertently tripped that particular switch on the way past...
posted by Brockles at 12:15 PM on April 7


It does depend on the sensor - but you can ignore Lambda (O2) and EGR sensors all day long on pre-2000 (or thereabouts) cars if you don't need your catalytic converter to pass emissions....

That might explain it - I grew up in Pennsylvania, where yearly inspections of not only emissions, but for the rest of the car as well, were legally required for the car to be street legal. So for many things, you had the choice of fix it now, or fix it in a few months when your inspection sticker needs renewing.

You may have inadvertently tripped that particular switch on the way past...

Understandable. The vast majority of my auto knowledge is 30 years old, and I welcome getting put straight about my assumptions. I generally tend to ignore any onboard warnings except those concerning oil and temperature and just trust my ears when driving. I have a general distrust of the CELs, often seeing them as just a way to scare you into having a dealer service them, even though experience has taught me that sometimes I shouldn't be so cavalier about it. I learned I had to separate the obligation of getting something checked out with the necessity of getting something repaired right then. For a long time I felt that having my car checked out and then not having it fixed after the mechanic went to all the trouble of diagnosing it was kind of an asshole move, but now that I have a good relationship with a couple mechanics in town, I feel a lot better about waiting because I know that they know I'll be coming back to them when I'm ready to get it fixed.
posted by chambers at 6:19 PM on April 7


The thing about the CEL (and I'm pretty sure I learned this from reading Brockles' answers here, it that the light and the error code don't really tell you anything useful. It's what is causing the error condition that is the important information. And that information is often impossible to even guess at from the typical Ask Mefi automotive post that contains only the barest of info. I was actually thinking of Brockles when I wrote the original question - trying to make sure I provided enough relevant info.
posted by COD at 9:04 AM on April 8


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