streetglower

iTrader: (13)

No this is not another thread on how to turn the check engine light off, but I have another issue to address.

Ok I had to make this thread to shed some light to people.

I have seen several threads during the cource of my time on 7thgen where people are having major issues with there car whether it be idle problems, tranny problems, or whatever and they dont know what to do or whats causing it. then come to find out that there check engine light is on.

Well, lets go over something here.

A car runs off of inputs which are sensors. Now those sensors send information to the ECU (basically send signals to the ECU) and based on those signals recieved at the ECU will determine what the ECU will send to various outputs which are actuators, solenoids, etc... and that is what runs your car

Now if your car runs good, then the ECU sees the right signals and sends info to other outputs and the car runs fine.

Now lets just say (I was use an example that I gave another member a few days ago) that you wake up one morning and get in your car and start driving around and after 5 minutes, black smoke is pouring out of your exhaust, you are getting really crappy gas mileage on your 1000 mile trip and have to fill up every 100 miles or so, and the car barely runs, it boggs down and even stalls out every once and awhile. And has problems starting. And your check engine light is on.

the first thing that people will do is wonder what the hell is wrong with there car. And the first thing they do is overlook the check engine light and start doing everything possible to fix it. Replace air filter, fuel filter, spark plugs, ignition coils, run higher octane gas, whatever so they dont have to take it in to the dealer and have to pay too much money.

Well back to the scenerio, after relacing all of these items, the car still runs like it did before and they give up and take it to the dealer. A few days later you get the car back with a brand new o2 sensor, no check engine light and the car runs like new again and you have a $40 bill for a new o2 sensor. and you are wondering what the hell? You just got done spending over $200 to try and fix it when a $40 part was the cause

Well now you ask how did my o2 sensor cause all of those problems. Well lets take a look. A o2 sensors job is to measure the amount of oxygen in the air before it goes to the cat converter. And based on that reading, the o2 sensor will send a signal to the ECU and based on that signal, the ECU will add or reduce fuel to the engine. Now if that sensor happened to fail and read extreme lean all of the time, the o2 sensor will think there is too much oxygen coming out and will instruct the ECU to dump the engine with fuel to compensate the over lean condition even though your engine is running fine. Now you are running extremely rich and have too much fuel entering the combustion chamber to mix with the air coming in resulting in the black smoke out the exhaust, bad fuel mileage, and stalling. All of these because one sensor sent a false signal to the ECU.

The point I am trying to make with this is if your car is running like crap, your tranny stopped shifting, your car has crappy fuel mileage, whatever and your check engine light is on, dont start throwing parts at the car to try and fix it, find out why the check engine light is on. I have seen people go to the extreme when there tranny fails and the check engine light is on and they replace the tranny cause they think its shot when all that was wrong was a bad sensor. which was a $20 part.

This goes for any other issues to. If your car doesnt start, a bad crankshaft positiom sensor not sending a signal to the PCM to let it know which cylinder to fire. That will cause a no start condition and throw your check engine light on.

Again I made this thread to let everyone know if your car is causing you problems and the check engine light is on to diagnosis that first because usually that is the cause of the major problem you are having. I am just annoyed on how many threads I see daily where people overlook there check engine light.


I am not here to try and explain to you how a car works or try and sound like the smartest person around, I am simply here to help everyone. I love working on cars and I hate when I see people not use common sense when trying to find out what is wrong with there car.

Jrfish007

iTrader: (3)

Good post!!!

For all those that go get the code read, go here to check what it means:http://www.7thgencivic.com/forums/sh...d.php?t=182026

jta

iTrader: (1)

Hi Streetglower,

Nice post, just wanted to conform with you my situation:

Civic 2002 (LX Sedan, Auto, 107k)

I have noticed while driving the rpm would flutuate or jump or drop abnormaly for a split second.

Can this be an O2 sensor issue, also the gas milage is not so great anymore.

Thanks.

Jrfish007

iTrader: (3)

My dad just told me the other day that his car seems to mis every now and then. He said he will be on cruise control or whenever and it just feels like the car misses once or twice and then it's fine. Rather wierd, I'm going to look into a little more.

jta

iTrader: (1)

I have the exact issue, except the cruise control part or may be I did not notice.

Lets us know what you find out, thanks.

digitaldemigod

I can't imagine not finding out first why the check engine light is on!

Mine came on and I assumed it was the o2 sensor... my father in law has a computer to hook up and read the codes from the car. I brought it to him and it actually was the EGR valve! Glad I didn't go buy a $60 O2 sensor. Instead I needed a $150 EGR valve and gasket!

Donggie

iTrader: (2)

I have the same exact problem and the code that is coming up is EGR, so I replaced the EGR and Gasket with a brand new one from Honda. Still has same problem. CEL is still there and it is the same code for the EGR - insufficient flow or something like that. Did replacing your EGR solve the problem? It didn't for me. Is there any other sensor or condition that could possibly give the same code? Can anyone help?

Thanks,

Don


Code: P0401 Exhaust Gas Recirculation Flow Insufficient Detected

call|me|G

is there anyway i can check my error code w/o having to take it to the shop??

Slammed99Si

First post here because I need some help - I just installed a Holley Warlock on my 99 SI and I bought a high flow cat (technically it is not really high flow even though it says that) and my check engine light has been on ever since. I have been driving with the check engine light on for over 4 months. I would like to know if I have damaged the car bad because I am worried. It still runs great and I have done oil changes ever 2,000 miles. Most importantly though I need to know how to get this thing off. It is driving me insane. I have replaced the O2 sensor and cat with brand new ones (yes I bought another cat because they are 25 dollars each) Anyway, one thing i just noticed today is the proper placement of the o2 sensor on my old cat was in the middle, and on the new ones its before the cat. I was thinking this is most likely the issue to why my check engine light it still on considering all the parts are brand new. any advice would be great. I need to know if I am on the right track. Because if I am the only after market Si cats are over 200 dollars (performance ones) and I don't want a stock one because it makes my exaust sound like ****. If there is a cheap way to fix this let me know. I was thinking of saying F*** it and drilling a hole through the middle of the cat to move the sensor so it will work with 96 model civics and up.

streetglower

iTrader: (13)

the reason why the light is on is because you said you dont have a actually converter in there correct? if there is no catalyst material in there, the light will come on because the secondary o2 sensor is signaling the ecu that there is no cat. also the placement of the sensor in the converter also has an effect. but if the cat converter you purhcased is just a "resonator pipe" then it will stay on. you can get an o2 simulator, but it just turns the light off. search up on it, there are plenty of threads.

Slammed99Si

Thanks for the tip -Although I read into those more and my car would not pass Echeck. I just ordered the stock cat and it shut the light right off. The only aftermarket one I have seen for my car was made by randomtechnology and costed way too much.

manaitico

hi my car has this code P0172 System too Rich (Bank 1) can anyone tellme how to fix it thx

Storm897

Check here

Also, try googling first. It was the first hit that came up on google when I searched for your problem.

bandjthorpe

my tach on the car and my 5" tach isn't working.. any hints?

sckew

I having problem the car stalled in the middle of driving, after that could not start over. after a few minutes or so, it will start up again, this is happening. the code P1361 was shown when check by mechanic..some even shows TDC sensor "noise", what is taht mean??

any one having experience..TQ

Ckutch02EX

My 02 ex coupe chck engine light is on again. the code reads for random missfires. I replaced the plugs several weeks ago and the light went off. tonight it came back on and the code is the same. I'm not blowing smoke, starting hard, lossing power or mileage, overheating or lossing any fluids. I don't know what the problem is and I just dumped 1500 into it for a tranny rebiuld(seperate problem) and can't afford taking it back to the dealer for this issue. I thought maybe the head gasket was going(NO smoke loss of fluid or pwer though).any ideas? pm me if any ideas thanks!

tinnguyen123

my check engine light is on.. and my mechanic read the code and they said i have 4 problem.. and its going to cost ALOT of money.. and the only thing i did was pulled out a fuse..AND i put it RIGHT back.. does anyone know what i should do..? is it anyway i can know for sure that there is a part that is broken..?

christallee3

did you ever fix your P0401 code??

beta2

Can someone tell me what could be the problem for my 2002 civic 4dr 1.7l; Once in a while (3-4 days) my engine light comes on, I lose power sometimes even the engine dies. With full throttle I get no more than 3000 revs and a diesel sound from the engine.
Useful to know that I checked the problem when the light was on and it said the fallowing:
P1361 TDC Sensor Intermittent Interruption
P1362 TDC Sensor No Signal
P1298 Electrical Load Detector Circuit High Input
P0420 Catalyst System Efficiency Below Threshold (Bank 1)
Changed new spark plugs, checked the coils everything works good, also I have a new air filter which I double checked and it was clean.
Other than that when the engine light is not on the car runs smooth.
I looked on the i-net that the fuel filter should last the life so I assume that it's the fuel pump... or I don't know.
Need a professional advice on this. Thank you

kirbyxray

HELP!! 2004 civic ex 1.7 automatic I have check engine light on
code said P2646 VTEC Oil Pressure Switch Circuit Low Voltage or FAILED switch
when I step on the car when it gets to 4K rpms its bounces like its hit the REV limit!
Bought NEW Vtech sensor and still same thing...
also having overheating problem.. new engine rebuild new head gasket new thermostat, water pump radiorator. Temp gauge goes to H then back to half way then climbs back up.
NO VISIABLE WATER LEAKS!

artivann

My 96 civic idole's up and down. What could be the problem?

artivann

oops!! (idle's)

Philnut78

The same thing is wrong with my '04 Civic VP. The original engine that was in the car seized up while under wanrranty. My honda dealer replaced the engine with a remaned engine got the car back drove to the house the MIL pops on. I take the car back the next day they told me DTC P0401 so they replaced EGR and gasket with a new parts gave it back to me not even a month later the MIL pops back on. I check the code its DTC P0401 so i take it back again different Service Advisor this time. They again tell me DTC P0401and replace the EGR and gasket with new parts. I get the car back and a few days later the MIL comes on again and its the same DTC P0401 & DTC P0404 (EGR Valve Insufficient Lift) so by now im sick of the dealer going through the motions and not fixing the problem. So I have a friend that was a Honda Tech so I take my car to him and we diagnose that its not a bad EGR by applying current voltage to it while car is on but not running. We also test all the wiring going to and from the EGR for a short and also to verify the correct voltage is where it should be. And it was so we remove the EGR valve and inspect the passage and intake manifold for blockage nothing. So back to the dealer it goes 2 weeks later the dealer tells me that the intake manifold and water passage and all gaskets and o-rings need to be replaced But that its not coved under the warranty due to the carbon buildup and itll be $1150.00.
So I tell them im not paying that im picking my car up tommorrow have it ready!! So now 13 months later and my reg is due and its mandatory smog in California every other year. So now Im screwed took it to honda dealer again and they charge me half price just $70.00 to clear the code i asked if they test drove it he said yes i asked did u get on the freeway he says no. I tell him test drive on the freeway he declines. So off i go to pick to pick it up and get on the freeway just to have the MIL come back on so i go back to the dealer they check and recommend replacing the EGR valve i tell them im not paying $370.00 for the same fix that didnt work the first 2 times. So what i really need is the wiring diagrams from Mitchell On Demand for my car. My friend got a copy of AllData wiring diagrams for my car but he says they are not thorough enough. Hes positve it is another cause for the MIL and suspects another sensor or system is just passing the code to the EGR. This was after we had cleaned out the intake manifold thoroughly. I think it is the ECU does not like the reman engine for some reason. Can anyone help.

THNX

daEM2guy

Im sort of having the same problem. EXCEPt My OBD2 scanner says erro when i plug it in and search what is wrong because my engine light came up. Also there is a green key that is blinkin continuously. Everytime i start my car itll start bogging. I checd my spark plugs they were all burnt up!!! car still starts and everything but its bogging when i giv it gas, Obd2 scanner not reading Error cod or no link,green key blinking,car boggs, smelling a mixture of gas fumes and somthing like burnt volcanic rock or sumthing,

CAN sumbdy plz help me figure out this problem plz !!!!!!!!!! this happned when i had finshed my motor swap same motor d17a2. i have a feeling its either the wire harness or da ECU :-/

daEM2guy

can anyone gime some info or tip what i shoult do? bump

Lonwel

ecu dudethe key light is def a sign that there is an ecu problem mine only comes on whn i turn the ting off (it's a reminder that the key is still in the ignition) so yah, big expensive problemo for you man, cuse the data link isn't connected it'd say it was the ecu or the harness is kaput for the connection, which i doubt, it's realy hard to say hat if you got the harness to run the car but the ecu connection is poopy, so i-d have your ecu checked and if it's good check your obdII port wires best of luck

88WAG

Streetglower, thanks for the awesome info.

88Wag

starlyn

my car 02 civic 02 HX, have the P0240 code and the engine light is on, but i never had seen a Honda with that problem, because every time i turn mi wheel to any side the car turn off, but it only mostly happen when the car is hot, i loss power every time i put up my windows or turn my light on. help ... one more thing how could i stop the belt engine noise im tire of the heeeeeeeeeeeeeeeeeeeeeeeeee noise???

Hooper_Sir13

got the codes p1298 and p1106 on my 2002 civic sir just changed o2 sensors and alternator help please

sdaidoji

iTrader: (1)

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instead of just posting, why not check the link i posted? ...
There is a difference when a thread says post questions or when a thread says please read this...