Just to fill you guys in on some backround information, lately I've been suffering from terrible gas mileage and I suspected it to be that I have yet to do my 60k tune up, currently at 80k right now. About a month ago my check engine light came on and last week I threw the ECU into its diagnostic mode, and it gave me the fault codes 04 03, Throttle Position Sensor (TPS), and 03 04, Knock Sensor. Two codes were triggered, now my question is does this means the part needs to be replaced? I found out that the price of these parts is going to run me roughly $60 for the TPS and $160 for the knock sensor and hopefully someone from the .org could shine a little bit of light on this subject.

I drive a '97 SE 5-spd with a y-pipe and a custom intake. Thanks guys.

 

Interesting question...

 

Before you replace any of the sensors do your 60k tune up - you will have to do it anyways and it may fix your problems.

 

these engines are know for knock sensor codes. change your knock sensor and knock sensor sub harness. the sub harness gets coroded and wires break . clears codes and see if tps code comes back, sometimes a bad knock sensor with set other codes like o2 tps and others

 

That's a good suggestion zirafa... I've reset the ECU and the codes havn't resurfaced yet. Is there any way to test the knock sensor to see if it really is bad? I tested the TPS already using a method I found on a website, that will have to be replaced, however the knock sensor is my main worry because it is quite expensive.

Another question how long, if at all, after the ECU has been reset will the codes resurface if there is a problem? If there even really is a problem. Thanks again guys.

 

if you buy ****ty gas the ks code will pop up...

 

That's not a possiblity, because I've never used anything lower than 91 octane.

I guess my real question is. Now that the CEL been set off by either the TPS and/or knock sensor does that mean it is faulty and needs to be replaced or is there a possiblity that it was triggered by a one time event?

 

Ummm It's just the opposite.

Change the TPS, clear the codes and see if you get the KS code back. Keep in mind that the KS code is stored when the KS voltage output is outside of the acceptable range. Which means it's doing it's job and could also mean it's detecting excessive knock & ping. This can be caused by quite a few things including the mods your running.

Change the TPS and tune up the car. Hopefully your KS code will stop coming back.

 

Unplug the KS connector from the harness and measure resistance between one of the pins and a good ground. IIRC the resistance shound be 550-630 Ohms (someone please correct me if I'm wrong). If you don't get reading from one pin, try the other one - only one is actually connected to the KS.
I changed my KS recently because the car felt sluggish. I tested it when it was still in there and it gave me some weird readings, so I figured it was bad and I was right - my car pulls a lot stronger now. I also tested the old KS when I pulled it out and it gave me the correct reading (WTF??). Bear this in mind - resistance changes with the temperature change and also the KS may be bad even if it gives you the proper reading.
One other thing - don;t know if you have found one already but a new TPS may be way more than $60.

 

The tune-up is in the works for sure. I just need to find a good source for parts.

I'll try your suggestion on testing the KS with an ohmmeter. Thank god I'm an electrical engineer, got all the tools I need to check all this stuff

 

It should measure very high resistance, almost an open circuit upwards of 10 Meg Ohms or higher. (Haynes Maunal)

550-630 Ohms is way to low.

 

Would having a bad knock sensor have anything do with installing a CAI recently? What can I do if I get the knock sensor code and have no electrical knowledge? Replace it, is it easy to install?

 

Then it must be 550-630 KOhms, but it certainly should not be upwards of 10 MOhms. IIRC the manual advises to use the multimeter capable of measuring upwards of 10 MOhms, probably so you can get some reading even if the KS is bad and has high resistance. I measured resistance on a brand new KS before I installed it and it was between 550-630 KOhms ( .55-.63 MOhms ) don't remember exactly. Anyway, it was well worth it.

 

Does the manual say anything about a malfunctioning knock sensor? I suppose it will just be out of range. or not even give a resistance at all.

 

how long do i need 2 wait before it resurfaces????? around september of last year i got the code 0409 for a oxegen sensor and i reset the ecu and i havnt seen it again until yesterday. im not really sure wat exactly that code is for and i am scared 2 take it to my mechanic because i am really short on funds. can anybody help me??????

 

I was thinking along the same lines there sagamax...

 

GO with nj 's idea. You should get out there with your ohms meter yourself and test some sensors and stuff. Its not that hard and its the same thing your mechanic would do. using a multimeter is relativly easy..

So how does it run again, after you reset the ecu, rough still.?
This seems odd with such low miles.