CEL Code PO546 No results In Search Box Here
 

So I got a (Solid Not Flashing) CEL last night while driving on the freeway at roughly 65mph driving normally.

I woke up and got in the car this morning to go to Autozone, started the car, and no CEL?! I still drove to Autozone hoping that the code was stored, and luckily it was. I was getting a PO546 Code which is Exhaust Gas Temperature Sensor High Input Bank 1 Sensor 1.

I searched our site for some help but came up empty in the search box. So I then went to NASOIC for some help with the search and came up with a few threads on it. Weeding out all of the BSer's and trying to suck up the genuine knowledge, I gathered that my EGT Probe sensor in the up-pipe is probably dying. What I also read is that it is much more common for this to fail in a catless up-pipe due to more exhuast flow and temp. I have a stock up-pipe in my 05 WRX so this worries me a little.

I have taken off all parts on my car besides the short ram intake and CBE due to my car being temperamental the last week and a half while driving to and from work. The intake is coming off also when I get a chance today for sure. The parts will definitely stay off until I get an AP or other engine management in the near future.

Most said that the CEL stayed on until they did something about it or reset the ECU. Even then when most people reset the ECU, the same CEL came back on without wasting much time at all. Knowing that the CEL turned of on its own without being reset on my car within 24 hours, and hasn't returned, am I over-reacting by thinking I need to replace the EGT Probe/Sensor or should I just leave it alone and wait until the CEL comes back?!

I think I am just nervous because all of this is going down right before the turbo and I'm scared of maybe killing something else or maybe sucking some stock cat or something in from the up-pipe?! I have been driving all morning with my car running as good as it ever has so I'm not sure what to do. It seems back to normal. If anyone has had this code before or can shed some light or advice on the situation it would be greatly appreciated.

Thanks in advance guys

I'd wait and see if it comes back. Engine management would be a good idea.

I hear ya, engine management is the next thing. I just don't want to sacrifice killing my turbo or something else more expensive than this part because I can pick it up for less than $100 and install in a few minutes. I've shopped EGT probes from $80-$120 today.

What's wrong: Either your UP cat is failing, your EGT probe is failing, or you are generating higher than typical EGT's due to another problem. None of these possiblities are particularly safe situations.

You said you removed all the parts. Does that include the UP? How's the cat look when you shine a flashlight at it? I'd imagine the sensor could be tested with an ohmmeter and a blow torch, but I'd bet it's the cat failing which might also explain why the car has been running poorly lately.

What I'd do: When upgrading the turbo, install a ceramic coated UP that doesn't have any bungs. Tuning will eliminate the CEL associated with removing the EGT sensor and it won't be necessary anyway, now that you have a catless UP. Consider installing an EGT probe in the headers for an aftermarket gauge.

Profit?

I did not take the UP off and look at it with the flashlight unfortunately. I never upgraded it from the factory one. Not to mention I have my roommates dirtbike and various other things that he just put in the garage so that I do not have any room to work on the car or even pull one in to check. I plan on doing an aftermarket UP in the future but want an AP first. I tried to take off the intake and put the stock one back in, but can't seem to find one of the plastic parts of the snorkel shit, so I aborted until I can go through the messy garage to find it. So as of now I have a AEM intake, Apexi Turbo Timer, Megan Racing CBE, and Megan Racing Springs. And I don't plan on upgrading the turbo for quite some time but appreciate the insight about the ceramic UP.

The AEM intake could be making you run lean, causing elevated EGT's, which might explain the CEL.

Noted, I have been told that before about the AEM intake. It is still on the car though. The car is very inconsistent lately. Sometimes the boost is all the way there even with the rough idle and what not, and then the next time it feels like I'm only getting roughly half my boost with a lot of stuttering to boot. And that is the thing, the CEL is and has been gone since that day. Hasn't came back. But the car is running the same inconsistency as the few hours it was on that night, terrible. Does anyone know if that is maybe a soft code or have any reason why it would have went away on it's own overnight?! So now I have no CEL and a bad running, and bad idling car with nowhere to look besides an EGT Probe as far as I know. Would a bad EGT Probe make my car run like this?! I was told that the EGT probe does nothing but measure the temp in the UP/voltage in sensor and if it is not within a certain window, you get the orange light of death in your gauge cluster. So if that is the case and I am getting credible info, that would make my car run like that would it?! I have more probs?

For the love of god! Ditch all the aftermarket parts until you've got EM and a proper tune for them!

We're not likely to figure out a solution for the problem over the internet. Do yourself a favor and take off the non-factory stuff. If it's still running poorly, then we might be able to start tracking it down. But if you've still got an intake on the car, we're all gonna guess that's the culprit, 'cause it's by far the most likely thing to cause the issue.

CEL's can come and go if the condition that caused them subsides. As you saw, they do often remain in memory though, but not always. It depends on the code. The UP EGT is pretty much like you described. It's only purpose is to ensure the UP cat doesn't get overheated. I've heard stories of cat material and even the EGT probe itself getting sucked right into the turbo. :eek:

Remove the intake, reset the ECU, and see how it runs and if any CEL's return.

If I could find the plastic piece to the stock intake that I'm missing (that is in the garage somewhere), I would love to remove the last aftermarket part! And unfortunately I can't just go bust out $1000 plus in the course of a week and a half on my car for an AP and a custom tune or I would love to do that too!

Thanks Cody, I wasn't sure about the CEL going away on its own. I don't want anything to get sucked in the turbo for sure, If that happens, I'll never get an AP! So I will get a new UP probably along with the EGT Probe just to be safe. I will also go to the garage today and find that missing piece and do the ECU reset and see how that goes. Thanks again for the help

I wouldn't bother. Just wait until you get the AP and can flash to stage 2 and replace the stock UP with an aftermarket one. It's like a 5 hour job, but not too hard. In the mean time, stay out of boost. You don't need an EGT probe in an aftermarket UP but installing one in the headers for a gauge is a smart move.

I know you can run an aftermarket UP with stage 2 (and you must have a DP too). Check the map notes (on Cobb's site) for stage 1 too though. An UP may be allowable with stage 1 as well (no other mods).

I plan on putting the one in the headers for sure for the gauge, that is why I will buy a new probe. I checked the notes on the stage 1 for my car and it says nothing about being able to run an UP or anything that is not factory. I finally found that last piece to the intake puzzle and put back on the stock intake and did an ECU reset like you said at lunch today. I took a really long lunch and put 20+ miles on it after the reset, and the car is still very inconsistent. It got a little better if at all. I had my friend take a couple of videos on his phone while I was accelerating to catch the inconsistency. The first video was in 2nd gear starting at about 3000 RPM on the tach. I was literally standing on the gas pedal and the tach was moving slower than just about any car I've seen. I would have gotten smoked by a 2.5 RS if he had started at the same point as me. It was real bad. The second video was from 1st gear through 3rd gear, and it was running like it did when it was new, great. Not to mention these videos were about 1-2 minutes apart from each other on the same road. I will definately stay out of the boost, I just had to see if taking off the intake helped at all. Not much if at all. It still stutters and surges really bad and I'm not sure what to do. I even had my friend that knows Subaru's really well and owns a WRX also to see if he could figure anything out and to show him that I wasn't crazy that my boost comes and goes as it pleases, and stutters when it does want to come out and play. He didn't know what to do at this point either. I don't know what to do at this point! I've been modding N/A cars since I started driving so I know what I'm doing for the most part, but this is my first turbo car. CEL did not come back on either!

Unfortunately it sounds like you should probably take it to someone. However, I'd probably start looking for a vacuum leak at this point. The easy way is to spray carb cleaner all over the intake tract from the MAF housing to the turbo inlet and check the throttle body, IC, and hoses to make sure everything is air tight. Careful with the bypass valve (AKA BOV) bolts. They'll strip real easy.

I'll check for vacuum leaks and do the carb cleaner when I get a chance today. I just have a prob because I don't know any good mechanics in town very well and most of the time they just throw parts at it and see what happens. I can do that myself and maybe save some labor costs in the process. Does anyone know a good mechanic in town?! I'm open to suggestions. I've already had experience with the BOV bolts taking parts off so I do know that for sure. Thanks again!

The only recommendation I've seen on this site is for Greg's Garage, I think.

It looks like that sensor can cause ALL of the symptoms you described. One wouldn't normally think so, being just a temp. sensor, but I suppose it's input is used for more than just a simple "how hot is it?"

Info: The last part under "Caution" means that it won't reset without using an actual OBD scanner, and clearing the self learning of the ECU. Sometimes, with hard codes, you can turn the light off by disconnecting the battery, but the ECU needs an actual reset to start thinking right again.

Awesome info Cory. If you don't know somebody who has one, Kavid, you may try seeing if AutoZone can clear the code with their free OBDII scanner service. Hopefully the only issue causing the code was the intake.

Great info sir, I really appreciate it! That is the funny thing is that the CEL turned off before I got in the car the next morning! It did reset on its own without the scanner! It did store the code in my ECU when I did go to Autozone though, but the CEL was not there. I did disconnect the battery when I took my intake off though yesterday to reset the ECU per codys guidance, and it seems to get a little better as I drive it. Do you know about how long on average the ECU takes to re-learn or what-not? I have put roughly 80 miles on it since yesterday on purpose to see if it would do that. Like I said it seems to get better as I keep driving it and definately no CEL has came back. And on the info you gave, I have had bad idling and poor driving performance but never problems with starting. Thanks Cory!

Good to know, I was on my way home and the CEL came back on. I'm actually kind of excited the CEL came back (that sounds weird). It will give a clue. The only problem with this is now I had no boost in second gear. I only gave it gas one more time with the same result in a different gear. I drove home and babied it very much. I will get it scanned tomorrow since autozone doesn't scan after dark for some reason when I called and have my boy follow me to Greg's Garage and have them take a look. Thanks for the mechanic reference sir

The intake has been off since yesterday morning, and it coded again this evening. see above

But you haven't reset using an OBII scanner yet.

Kavid, if you're coming to the meet tomorrow night, I can bring my scanner, and we can take a closer look. If it's the same code for the EGT, it's most likely that you'll end up needing to replace it, and then reset the ECU again.

I'll be sure to bring the scanner with me!

Resetting the ECU with a scanner, and clearing the "self learn" that I spoke of, means that the ECU is cleared of all of the monitor setting items, and the adjustments it makes to fuel/ignition timing, etc., according to the way you drive. Even when the light turns itself off, any adjustments or fail safes it's set to keep from damaging the engine due to the part failing don't reset themselves. It's gotta be done specifically with a scanner, which I'll be sure to throw in the car tomorrow, in case you can make it out! :D

Thank you very much Cory. I am going to go to autozone on my lunch today and have the code checked, but I will make sure that they do not clear the code or reset anything. Depending on what the code is, whether it is the same one or not, I will either buy the probe, or take it to Greg's Garage or someone who knows what they are doing if it a worse code. Because I have no boost I am trying to drive the car as least as possible. If I can talk the girlfriend into letting me come or maybe drag her along for a few minutes I will definately be there at the meet to at least see you. It is Valentine's Day and all, but she understands how important cars are to me. Autozone's scanner isn't the greatest but it is free though. I'm crossing my fingers and hoping for the best. I hope to see you guys tonight. Thanks again

I did though. I took off the intake, reset it with disconnecting the battery, and also had the Autozone guy do a reset with his scanner also from guidance from another friend of mine. He said the battery trick wasn't enough so Autozone did it afterwards.