I'm looking for some techies to help explain this to me ...

A couple weeks ago, I was on a short trip when the car start to shake at low speeds and I saw some smoke / smelled electronics burning. By the time I pulled over, I let the car cool down - the smoke stopped. I limped it back home and straight to the dealer.

They said the ECU was bad and that 3 coil packs had to be replaced. I got it done ... and everything is running smooth. A few miles later that night, I notice the SES come back on. I took it back and they said the B2 Cat & rear o2 sensor needs to be replaced.

I could understand if the o2 sensor went bad because of the smoke or ECU inadvertently frying it .. but the cat, too? All of a sudden?

is it possible for the car to detect a bad cat or does it make that assumption simply when the O2 sensors go bad?

Thanks!

 

How many miles on the car?

I'm a firm believer that if you need to change one coil pack, you might as well do them all at once.

Regarding the cat, no, the ECU does not detect a bad cat, just bad O2 sensors. Crawl under the car and gently tap the cats with a rubber mallet. If you hear anything loose replace them.

 

Okay - thank you for answering the question on the ECU detecting a bad cat. That's what I thought.

There's less than 60k on the cats and o2 sensor.

You think the smoke or driving the car with the bad coils messed the sensor up?

 

Anything is possible. Try resetting the codes and see what happens

 

I will rent an OBD2 scanner from autozone today and give it a whirl. I reset the ECU codes like 4 times in hopes it would just go away for good lol. It keeps coming back

 

OK. Then forget the code scanner. Replace the O2 sensors, both of them. Use OEM NTK sensors.

 

Dealers tend to be overaggressive when it comes to repairs. Rather than troubleshooting 3-4 hours to replace a small dollar part, they just replace the entire unit once they conclude it's part of the troubles.

Personal experience. Friend's car ran like crap. Went to dealer and got quoted a high sum to replace a body harness and two O2 sensors. We put the car up on our own lift after and took a peek and found a sliced harness (road damage). An hour with a soldering gun and some heat shrink and problem was solved.

I'm not saying they are ripping you off, but I would take their diagnosis with a grain of salt. Sounds kinda odd that all the sudden 3 coils, an ECU, a cat converter and O2 sensor all STB at the same time. Who knows.

 

I have to agree with Mustang on this one. Seriously doubt the ECU needed replacement in the first place. Coil packs and O2 sensor, yes. The only other thing that makes me wonder about where you took your car is that they only recommend replacing 3 of the 3 coil packs. Normally they will suggest as I did earlier, replace one, replace them all because the rest are probably on their way out too.

 

thanks to CA law, autozone doesn't allow customers to borrow OBD2 scanners anymore ... will ahve to buy one at walmart tomorrow and give it a shot. I want to confirm which sensors are showing up as bad before dropping $$ on those expensive little things.

I'm assuming sites like http://www.orderinfinitiparts.com/ will be good? I see them listed at 150 a piece.

 

I'm not going to argue whether or not all coil packs should be replaced at once but I will share my experience. My car currently has ~162k on it. Around 20k ago I had some rough idling upon startup and a code that indicated a misfire on one cylinder. I moved the coil pack on the cylinder that threw the code, and when it happened again it was the cylinder I moved the coil pack to. I only replaced the one coil pack and it has been fine ever since. Perhaps they are on borrowed time, and when the next one goes I will likely do all of them, but 5 of mine have 162k on them.

O2 sensors gone at 60k? That sounds premature to me too, although I don't know what that first event you had caused. My O2 sensors are still original, as are the cats (thank God).

I did have to change the cam/crankshaft sensors about 10k ago.

Sigh. But now I need a new AC compressor. I can buy one online for $472 but the stealership wants like $922. Something is not right there. I have to find a shop that will let you bring in your own parts, those are getting harder to find. The one I used to use does not do it anymore. I know they warranty their work, and I can see them not wanting to use non-OEM or used OEM parts because of that, but if I buy a new OEM part, sheesh.

 

I pulled off the driver side rear coil and this is what it looked like ... the left picture is right out of the cat; the right is what it looked like after hitting it with a MAF air sensor cleaner to take a better look. Also, I ran an OBD2 scanner and it threw only the P0057 code which indicates that sensor is inoperable.



I'm assuming it shouldn't look so mangled and dirty ... ideas what could have happened to it?

A rubber mallet to the cat didn't result in any rattling noises so I'm hoping it's okay.

 

That looks like something hit it.

Is the cat broken? Even if it was i can't imagine it would have enough mass to damage the O2 sensor like that. Those cats are pretty porous and light.