I've tried searching / looking through the threads for an answer to my issue, but the answers I come up with are so general I am not sure if they fit this specific problem.

I have an '04 6MT Nav with now 80k miles.

My "Check Engine" light has been on for the past 3 days.

I have refilled with fuel twice (road trip) and have checked the tightening of my fuel cap each time. A loose cap does not appear to be the issue here.

At idle, the engine's idle state RPM's are dropping to a rough feeling 500, and with the A/C running, it starts getting really warm really quick. Also, the engine feels a bit rough anywhere from the 500-900 RPM range. To remedy this I can usually give it a little gas in neutral to bump up the RPM right to about 1000, and the engine seems to smooth out and get the A/C working effectively again.

Everything seems fine once the car is in gear and moving, but the "Check Engine" light stays on constantly.

Not having taken the car in and paying for a diagnostic yet, I am wondering if the o2 sensor is most likely going to be the part that needs replacement.

I haven't tried disconnecting the battery and letting the ECM reset itself. I figured it would have probably reset itself over the past 3 days if it were a fluke?

Just trying to gear up early mentally for how much this is going to cost to remedy.

Any cheap solution or mechanical opinion is greatly appreciated!

 

Yep, sounds like it could be the O2 sensor. I had similar problems when mine went out. See if you are throwing CEL P0135. If you go to an Autzoone they can pull the code for you.

 

Is there a way to pull the Diagnostic Trouble Code(s) on the TSX without a scan tool?

Jumping terminals 4 and 9 of the OBDII Data Link Connector on the RSX could get you the codes without a scan tool.

Just wondering if the same/or similar applies to the TSX.

Otherwise, AutoZone will be a stop for me.

 

I forgot to mention the blowing FAN on the A/C is also slowing down when the RPM drops, too... and quickly sounds as if it comes back to full blast when I give it gas.

So along with the A/C's cooling effectiveness deminishing at idle, the "fan" blowing speed is also being affected.

I am wondering if maybe this is some kind of charging problem and possibly the "Check Engine Light" is an after effect due to the slowing idle state or otherwise.

 

Not sure of the proper name, but sounds like your Idle control module is bad. If there is any load on the engine, the module will idle the engine higher to compensate for the load.

 

Your best bet it to find a friend with a scan tool or go to Autozone/similar to get the code pulled for free.

Then either search "Honda diagnostic code Pxxxx" in Google for the translation, or ask here. From there you can easily narrow down the problem.

I'm putting my money on the primary O2 sensor, which costs $220 CAD at cost from Honda/Acura. Probably similarly priced in the USA. Installation is a breeze DIY.

 

As a follow-up, the code did come back P0135.

o2 Sensor problem.

Thanks for the input(s) / diagnosis!

 

I'm having the damn'est time trying to get the old pre-cat o2 sensor off. I've tried everything, even trying when the car has been driven for a long while so that it's well heated.

The sucker just won't un-seize, but then again I don't have access to a lift so getting enough torque using one hand under the car isn't easy. I'm afraid if I put much more force than I already have I'm going to sever the cat. conv from the exhaust.

Anyone have any suggestions for getting out a stubborn o2 sensor (aside from penetrating oil & the likes and heat), besides using a blow torch?

 

Use a long, strong wrench and have the sensor unplugged. Mine was stubborn but came off with a bit of muscle. I was under the car (front on jackstands). Wear safety glasses as dirt or rust will fall on you while down there wrenching away. I learned the hard way.

I'd also give it a shot of penetrating oil a few minutes before wrenching on it, just to help out.

If you break the connector bolts to the cat before the O2 sensor comes loose, there would be a serious problem with whomever installed the original sensor. LOL! Basically: Don't worry, the 3 bolts to the cat are damn strong and you won't break them.

 

You might have to get a shop to do it what they would do is lightly heat up the area by the sensor since its already damaged, its doesnt matter, then try to get it out. I had mine replaced and switched into the high flowcat and both shops did that same way.

 

I got the same error at 41 thousand miles, where is this o2 sensor located in the Cat Converter !

 

There is a wire going into the cat on the driver's side. There is only 1 wire connected to the cat. You will most likely need to remove the heatshield to get full access to it.

 

P0135 refers to the Primary Air/Fuel O2 sensor in the header. The one in the cat is probably fine. It's usually the primary O2 sensor that goes, I haven't heard of a failure of the sensor in the cat yet.

 

I am still lost; I dont know which one his is it ?

 

Other question what do p0420 means ?

 

A google search gave me this: http://www.obd-codes.com/p0420

 

Now I understand it means, but I have a o2 sensor problem to. When I put it on the computer its also stated primary o2 sensor not working, where can I find the primary o2 sensor or what part number is it so i can order it ?