The order you should replace or fix multiple CEL codes which include the KS
05-15-2002, 08:21 PM
#1
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The order you should replace or fix multiple CEL codes which include the KS
I just read an interesting thread. A guy has two CEL codes. Knock Sensor- 0403 and Engine temp coolant sensor- 0103.
Some on here would just replace both sensors, but thats not the case. The KS in our cars come up quite easy. Thats it job, to detect knock. It's going to warn you if it does too.
If another code such as 02's or the engine temp sensor come up, or any other emmissions contorl device. Fix or replace the sensor or device first. Reset your ECU and see if your KS code comes back.
I bet 95% of the time the KS doesn't return.
If our engines aren't running right, chances are they will ping or knock. Especially the engine temp sensor. If the ECU can't tell the temp of the motor, it may run to rich which will definately cause it to knock and ping. Enough of it will cause the CEL light to trip. Thats what it's supposed to do. It may also be the KS itself, but I'd only suspect that if only that code comes up.
Some on here would just replace both sensors, but thats not the case. The KS in our cars come up quite easy. Thats it job, to detect knock. It's going to warn you if it does too.
If another code such as 02's or the engine temp sensor come up, or any other emmissions contorl device. Fix or replace the sensor or device first. Reset your ECU and see if your KS code comes back.
I bet 95% of the time the KS doesn't return.
If our engines aren't running right, chances are they will ping or knock. Especially the engine temp sensor. If the ECU can't tell the temp of the motor, it may run to rich which will definately cause it to knock and ping. Enough of it will cause the CEL light to trip. Thats what it's supposed to do. It may also be the KS itself, but I'd only suspect that if only that code comes up.
05-15-2002, 09:12 PM
#2
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Join Date: Sep 2000
Posts: 966
so what you are saying is that there are a bunch of possible reasons as to why a knock sensor code would be set, right? i got a rear heated O2 sensor code in addition to the ks code. i should change the rear heated O2 sensor first and if i get the ks code, change that? i REALLY don't want to change both
05-15-2002, 09:25 PM
#3
I agree that the other codes should be checked first seeing as many codes can help contribute to the KS code. Also clean off the grounds for the knock sensor. They are 2 10mm bolts located just in front of the intake manifold. This may also help eliminate some power loss in the midrange as noticed by some members.
I would be interested in a thread that showed at how many miles most people replaced their knock sensor. I will have my intake manifold off in 2 months or so and really don't want to ever have to take it off again.
-hype
I would be interested in a thread that showed at how many miles most people replaced their knock sensor. I will have my intake manifold off in 2 months or so and really don't want to ever have to take it off again.
-hype
05-15-2002, 09:35 PM
#4
Yes this is true I had the 02 senser code and the knock senser code by just replacing the 02 senser the knock senser code went away and never came back and this was a year ago.
Thanks for bringing it up NJMAXSELTD, but you have to give some credit to Daniel B. Martin he's the one who told me about it.
Thanks for bringing it up NJMAXSELTD, but you have to give some credit to Daniel B. Martin he's the one who told me about it.
05-16-2002, 05:40 AM
#5
I checked my ECU the other day and got one code: 0304 - the knock sensor. So I checked the sensor resistance and it came in at 24 megohms. A new KS measures 560 Kohms, so I figured I needed a new one. Now here's the weird part. I reset my ECU and drove it a couple of days before getting the new KS (haven't installed it yet). I rechecked the ECU, and now I'm still getting 0304, but I'm also getting 0707 - rear O2 sensor, just like some of you guys.
Weird, huh?
So now I have to make a choice. Replace O2 sensor first and see if the codes go away (thereby saving some money, since O2 sensors are cheaper than the KS), or, since my KS resistance was way high, go ahead and replace it and see if that does the trick. Or replace both and be done with it.
Weird, huh?
So now I have to make a choice. Replace O2 sensor first and see if the codes go away (thereby saving some money, since O2 sensors are cheaper than the KS), or, since my KS resistance was way high, go ahead and replace it and see if that does the trick. Or replace both and be done with it.
05-16-2002, 05:44 AM
#6
That brings up a question:
Does an 0304 code appear whenever the KS senses some pinging (and is otherwise functioning normally), or just when the KS sensor starts to go bad (resistance measurement deviates from normal).
If the KS trips a code just from sensing pinging, then people are replacing it for no reason.
Does an 0304 code appear whenever the KS senses some pinging (and is otherwise functioning normally), or just when the KS sensor starts to go bad (resistance measurement deviates from normal).
If the KS trips a code just from sensing pinging, then people are replacing it for no reason.
05-16-2002, 05:55 AM
#7
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Max4U - Danial B. Martin was one very informative member. He is missed by a lot on here, thats for sure. He was Maxima.org's live service manual.
The knock sensor detects knock and reports it to the ECU by changing it's resistance. Lets say for example 560 ohms is normal, now I'm not sure which way it goes, but when knock or ping occurs, the resistance of this device changes. Maybe it goes lower or higher, I'm not sure. The ECU detects this and makes adjustments in the timing until the KS resistance is back "within spec". If the ECU can't get the KS back into spec because of excessive knock/ping, it throws the KS code. Thats the sequence in which I believe it works. So if you get two codes which include the KS, chances are the other code is your problem, not the KS. Like I said, I bet 95% of the KS codes are not the sensor itself, but something else causing the ping which is setting off the KS code. A quick measure of the KS resistance should reviel it to be good. Approx - 560 ohms.
The knock sensor detects knock and reports it to the ECU by changing it's resistance. Lets say for example 560 ohms is normal, now I'm not sure which way it goes, but when knock or ping occurs, the resistance of this device changes. Maybe it goes lower or higher, I'm not sure. The ECU detects this and makes adjustments in the timing until the KS resistance is back "within spec". If the ECU can't get the KS back into spec because of excessive knock/ping, it throws the KS code. Thats the sequence in which I believe it works. So if you get two codes which include the KS, chances are the other code is your problem, not the KS. Like I said, I bet 95% of the KS codes are not the sensor itself, but something else causing the ping which is setting off the KS code. A quick measure of the KS resistance should reviel it to be good. Approx - 560 ohms.
05-16-2002, 07:22 AM
#8
Senior Member
Join Date: Nov 2000
Posts: 677
What I want to know is with all the people installing new KS's, who is still tripping the CEL with 0304.
I've gotten the KS on and off for the past 20k. It use to come on with the Oxygen Sensor code, now it just comes on by itself.
95 max 160+k
I've gotten the KS on and off for the past 20k. It use to come on with the Oxygen Sensor code, now it just comes on by itself.
95 max 160+k
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