I have a CEL in my 99 max, I pulled the codes today and it came up as the 304 knock sensor. My question is that I read somewhere that the knock sensor will not trip the CEL but I did not see any other codes in there I don't think. Could this KS have caused the light to come on? Thanks in advance.

 

The KS should not trip the cel if that's the only problem. Did you clear the ECU before trying to pull the code? I only ask because I have a reoccuring problem with the vehicle speed sensor that will trip the cel [when it's raining]. If I pull the codes with the cel on, I get two for the vehicle speed sensor and the knock sensor. If I clear the codes first, then pull them, I just get knock sensor.

 

I did not pull the codes from the ECU manually, I took it to Autozone and the guy there used one of the code scanner devices and said it was the knock sensor. They wanted $169 for the sensor there, I got one on Ebay for $95. I will change that then reset it ECU, hopefully I will not get any more lights.

 

go to tire kingdom or something like that and talk to a tech give him like 10 bucks and he will test your car the ones at advanced sux
btw normally it is the O2 sensor that will trip it and since it is the most common to trip go and look for it

 

Hey everyone,
I have replaced the vehicle speed sensor on my 96 maxi and the check engine light still comes on. Any ideas on how to find the problem? i can't get my smog test approved until the light is off. California policy, yech!

 

Check to make sure the wire to the ECU has not been clipped. I have heard of this from guys clipping the wire to bypass the speed limiter.
Jim

 

Yes a bad knock sensor can make your CEL come on.. It doesnt always however. If the code is by itself change the sensor and harness.. they both tend to go out.

As for the speed sensor, you do realize you have to clear the code right?