I can't really say about the 02 sensor. Mine read wrong months ago. I cleared the light. Hasn't came back since. So not much experience. However one thing I've learned is just go to a parts store from now on. I know it's more expensive but 90% of their parts are warrantied and you don't have to ship them back yours and wait. But if you don't care about time that's up to you. Sounds almost like a harness problem but I'm sure yours came with a new harness. Make sure your heat shield around the harness isn't cutting into any wires upon installation. Shorted wires on the component actually calling for the power could cause inactivity because it's not getting what it needs due to the current being leaked elsewhere. But that usually blows fuse #4 under dash. Hmm... Maybe apply some dielectric grease on the connector. Problem may be on the engine side instead of the sensor side.

Also, as far as the rev limit goes. Check this out.

https://forums.clubrsx.com/showthread.php?t=588051#/topics/588051

Seems like our gauges can be a little unreliable by just a teeny amount. I think mine revs to 8500. Only hit it twice though. So I can't recall. I shift right after 8-8200. Not the answers you were looking for but it may help a little.

 

thank you, i don't have a heat shield as a have an aftermarket header. so should i just follow the wires and see if theres any problems with them and check the connector?

 

And also I've learned there's all kinds of stuff tied in to unnecessary circuits in these cars. Don't rule out checking every single (AND I MEAN EVERY SINGLE) fuse under the dash and the hood.

 

That's what I would start with. But I was referring to the heat shield that comes on the 02 sensor itself. It's like black mesh. It slides over the wires themselves where it hooks into your exhaust. I may be thinking of the secondary 02 sensor though. But anyways, yeah always start with the simple stuff. Especially since you've already replaced it twice. Like I said, dielectric grease wouldn't hurt. Like $3 for a little tube at any parts house. Then check every fuse under hood or dash. And if that doesn't clear it, I'll be looking for other solutions to try and help. I know this shit is irritating. Trust me. Lol

 

Also, what kind of gasoline are you running? Have you tried to clear the light yourself after the new sensor?

 

I'm running 93 octane from shell and i've cleared it like 8 times? always comes right back on. the scanner says that the sensor is staying right at 1.25 volts. I'm off tomorrow afternoon and I'm gonna check it out under there then.

i also read on some generic website that a coolant sensor could cause it, but i haven't seen that anywhere else. when i got my car the previous owner had cut the wires to the coolant sensor on the radiator and has them tied together. doesn't really make sense to me that that would have anything to do with it though

 

Seems a teeny bit high if it's constantly at 1.25V meaning your car is running a little rich. Should be at about 1 volt. Don't quote me though. Rich meaning not enough oxygen detected in exhaust gas. Maybe check for exhaust leaks somewhere before the sensor since you have a an aftermarket header. Try getting gas somewhere else too. Sounds stupid but all gas isn't created equal. Some dirty. Some clean. Put some injector cleaner in the tank next fill up too. Seems like there are quite a few problems that could cause this. I just hope and pray you never get the dreaded battery light issue that I'm dealing with. 2 new remanufactured alternators. New battery. No voltage draw while car is off. Usually the voltage regulator inside the alternator and people go through 2-4 units before finally getting one that fixes the problem. Ask me how I know to not buy certain parts off of eBay. ? An alternator is one of them.
Let me know how tomorrow goes.

 

For an 02-04 redline is 7900, fuel cut is 8100. My experience when running a race header. no matter what I tried I always ended up with an error code for the secondary O2 sensor. The only real fix for me was Hondata K-Pro 4.

 

What's the actual DTC you're showing? 0-1.25 volts is normal operating range, .1-.9 volts at idle. As Cjones mentioned, 1.25 volts means you're running rich. The service manual states that the secondary sensor readings are also used to determine fuel trims as well as cat efficiency. I've seen typos in the manual before, but this was pretty clearly stated. I'd throw that secondary back in.

The sensor in the radiator that you're referring to is the fan switch, not the ECT sensor. If that's disconnected, I'm willing to bet that you do have Kpro or Ktuner. There's no other way for the fans to operate. You would have to look inside the ECU case, not everyone has stickers on them.

Our tachometer's are definitely off by a bit, mine specifically is 200 rpms higher.

 

the code was p0134. when i got my header the secondary sensor had already went bad so i just never worried about it again since i didnt have a cat anyway and my cel was already burned out, so ill have to get one. what would i be looking for in the ecu?

 

^ This guy ????

 

Copy that. We'll figure it out. Just keep us posted.

 

Yes, and you check the relay for continuity with a multimeter. There's a couple of steps, it would be best if you downloaded a copy of the service manual. The diagrams will help. There's a thread on here with a link to download it for free.

 

i don't have a computer. only the one at work and my phone.

 

You can download it to your phone if you have a file viewer. I know iPhones can for sure.

 

so the ecu is stock. i checked all the plugs and the o2 relay/ fuses. all were good except for the bose system fuse which i took out to replace a different one i had blown a week or two ago since i unhooked all the bose things. on my scanner for the o2 sensors it says O2S11 and O2S12. the O2S11 stays at 0 and the O2S12 stays at 1.275 now. at first i would assume that O2S11 would be the upstream, but it is at 0 volts so it would make more sense for it to be the downstream since i don't have one.

 

I'm thinking the previous owner removed the hardware when he sold you the car. If your fan switch is cut, there's no way for the fans to run unless the calibration on the ECU is instructing them to run based on readings from the ECT sensor. What does your temp gauge show when you're driving? What about fuel system status?

O2S11 should be your primary. I can only think of two other problems. The primary is plugged into the wrong harness (would make sense with what you're seeing on the scanner), or the tip got dirty or damaged when you were installing it.

 

You mentioned in another post that you had a k24 bottom end? Might be worth mentioning when troubleshooting something like this.....

 

Not really relevant here. If it was a lean code or a mechanical problem then yes. This is an electrical gremlin.

 

the guy i bought this bottom end from put a k24 bottom end on his car. i broke my knock sensor when pulling my motor and he kept the k20 sensor and gave me the k24 sensor. so i just have a k24 knock sensor and a stock k20 bottom end

 

the fans turn on when the key turns on. the temp gauge works normally except it reads a little high. when i turn start it or turn the key on it goes up to like 1/4 then when it gets to temp it's a little under 3/4. wrong but it works. if you mean the gas gauge it works good. changes depending on the slope of where i park?.

i thought about it being plugged in wrong too and i looked at the plugs when i was under it the other night and the two sensors can't plug into each other.
and i guess it's possible i damaged it or got it dirty but twice?

 

also the previous owner did remove a few things. some wires were ran for subs and fog lights but neither were on it. i think there was something else to but i don't know.

 

The dude that sold you the car is a real McAsshole…

First things first, get everything back to the way it should be. Reconnect the fan switch, throw a secondary back on there, and diagnose that ECT sensor next. It's on the drivers side of the head, closer to the front. I can't remember for sure, but 3/4 up on the gauge is at least over 220 degrees. Those fans are supposed to come on between 196-203 degrees (at the switch, not the head), not as soon as you turn the key.

If you weren't aware of how delicate the sensor is, it can definitely happen twice. And I'm assuming you were probably in a rush because it was the second time you had to replace it? lol

where did you buy the sensor? and I know that I already asked this, but you're 100% sure that you have the proper sensor for your generation? Part #234-9005

 

the coolant temp stays around 183 or so after it warms up is what the scanner says. when the car is all the way cold the gauge is at about 1/4 of the way and then goes up about hallways to 3/4 after it's warm. it works normal just up higher on the gauge than it's supposed to. might be something similar to how the rpm gauges are off some. idk.
but i got the sensor off ebay. it's a denso. had the right part number on it and everything. i looked up pictures of the 05-06 and it looks different than the one i have also.

 

That sounds like another electrical problem. There's a self diagnostic function for the gauges assembly in the manual.

 

There's a video on YouTube where a guy shows you how to "calibrate" your gauges. I mean, they just go from lowest point to highest point. With ignition off, turn lights on. Push trip knob in. Turn key on. Lights off, on, then back off. Then hit trip meter 5 times and all gauges will zero out then max out. Not sure if this would help his problem. I don't think it calibrates them.

 

yeah. i tried that and it didn't change anything. i don't remember if it worked properly during that or not besides that it went all the way up. so fix the coolant sensor and put a secondary back on and if i still have to code i should try another primary?

 

Yes, but I would double check all of your fuses before purchasing another primary. and I would purchase it from a reputable place, like here.
https://www.kseriesparts.com/DEN-234-9064.html

I try to never purchase from Ebay if I can avoid it. Prices seem to good to be true most of the time.

and then I'd take it to the dealership if it's still not fixed lol

 

Any luck?

 

im waiting untill thursday to get paid. project this week was charging the ac again and the getting the miata running and ready to sell. i found a real clean civic hatch for cheaaaap that will be joining my fleet of non running cars after the miatas gone
thanks for checking in. hows your battery light problem?

 

im waiting untill thursday to get paid. project this week was charging the ac again and the getting the miata running and ready to sell. i found a real clean civic hatch for cheaaaap that will be joining my fleet of non running cars after the miatas gone<a href="http://forums.clubrsx.com/images/smilies/smile_color.gif" border="0" alt="" title="Smilie" ></a>
thanks for checking in. hows your battery light problem?

Nice!! Let us know how it goes. Battery Light is solved. Had to go through 3 remanufactured alternators before I got one that turned the light off. But now dash is clear. For now... Lol.

 

Troubleshooting the wiring for this based on the shop manual

I'm troubleshooting the same sensor with the p1166 code. The shop manual shows test leads at the ECM/PCM such as the image attached. My question is are the readings done with the connector still attached to the ECU (from the wire side of the connector)?

 

I'm troubleshooting the same sensor with the p1166 code. The shop manual shows test leads at the ECM/PCM such as the image attached. My question is are the readings done with the connector still attached to the ECU (from the wire side of the connector)?

id say probably not but i have no idea so :dontknow: i believe you usually have to replace the sensor when this code happens, that or a wires cut somewhere.