maximus_96

iTrader: (5)

last night i was successfully able to remove the knock sensor only to find that the two prongs in the sensor measured 550 ohm(or kilo ohm or whatever the unit is), exactly the same as the replacement i bought! i figured what the hell since i already bought the new one and replaced it. reset CEL, then tested for codes again and 0304 popped up immediately. i thought it might be the harness and went to buy a new harness this morning. reset and retested CEL and same thing there still. what else can i do? i read that to test the sensor by probing one of the pin and engine ground with a ohm meter, i tried and always get 1. please help.

nitink

I think you have to clear the code, it won't go by itself

Cdg2125

iTrader: (7)

Well sometimes the ks throws codes when its fine. If you replaced both the ks and the wire then there is nothing wrong with it.

maximus_96

iTrader: (5)

i did reset the codes. but tested for it again and it came back. when you guys test for resistance from the harness with the sensor plugged in, is it suppose to show the same amount as testing the two pins on the sensor itself? i get 550 from the two pins on the sensor but if i probe one pin on the sensor with one lead and the other lead to ground, i get a reading of "1". can somebody clearify that please?

also, what i don't understand is how you can get a reading at the pins in the socket. the sockets has two pins but on the sensor side there is only one wire. i cut up the old harness to see that the black or ground wires just ends there and not connected to anything. so with the sensor plugged in, the two pins in the socket on the other end is not closed and should be infinite resistance. the haynes manual said that if the reading is infinite, then the sensor is bad. thats why i thought mine was bad and bought a replacement. but testing the new sensor in the new harness also still shows 1...

Maxima880

From FSM
Knock Sensor Diagnostic Procedure

1. Loosen and retighten engine ground screws (front of intake manifold)

2. Check input signal circuit - 1
Ignition OFF
Disconnect ECM harness and knock sensor sub-harness
Check continunity between terminal 1 of sub harness (connector on top, left pin) and ECM terminal 64
Continunity should exist
If OK check harness for short

3. Check input signal circuit - 2
Check resistance between terminal 1 and engine ground
Resistance appx. 500 - 620 K omh
If OK check harness for short

Inspect knock sensor
Check resistance between terminal 2 (left pin) and ground
Appx 500 - 620 K omh @ 77 degrees

maximus_96

iTrader: (5)

ECM is the big wiring harness on the ECU right? or am i mistaken? how can you physically test for continunity between the knock sensor harness in the engine bay and the ECM in the cabin? please correct me if i'm wrong.

Maxima880

You have to run a wire to extend the reach of one of your test leads. I'll help you with finding terminal 64 if you need.

njmaxseltd

iTrader: (19)

Codes don't register immediately, they take at least two complete driving cycles of failures to record. I suspect you never cleared the code correctly.

Drive the car for a week and check for any stored codes once again.

pmohr

iTrader: (26)

My body harness is open or shorted between the ks subharness and the ECM, and after clearing the code with the screw or an OBD-II scanner, it'd pop back up instantly. It stopped doing this when I ran a straight wire from the body side connector to the ECM connector.

matrix11229

Tighten the bolt on the KS.
When I replaced my KS and reset the ecu the code returned as a ghost code (no cel). So I inserted a wrench there , tightened it and no code since then. I seen some threads here about KS problems and they said if the bolt is overtightened or undertightened the KS will partially work.

jalanb

I have had the same issue...replaced the KS and even today when I run the codes, it comes up twice on the reader.

GodFather

iTrader: (10)

You'd need to torque that knock sensor down to the recommended specs. Our knock sensors are sensitive piezoelectric transducers. They will need to be compressed correctly to get the "engine noise". If torqued down too light, they will not hear much, or they'll even vibrate, creating additional frequencies of engine noise, and possibly crack the sensor again. If it's torqued down too tight, it will be too sensitive and also pick up additional noises, this will make things harder for the ECU to interpret what's really going on. You'd have to search the torque specs about it, I already forgotten all the numbers.

You'll also have to check your O2 sensors. These O2 sensors, when partially faulty, will not trigger CEL's unless driven a couple hundred miles, upon and after reset. If O2 is bad, 0304 code may or may not appear recursively.

-Peter-

chinaman

Don't mean to hijack but I can't post yet, that damn limiter is getting old.
At any rate I just replaced the knock sensor in my 95 max, code is still there as well. I reset the ecu, I believe anyway its the same process as pulling the codes right? turn the screw, turn it back turn the key off good to go right?

Anyway yea 0304 is still there, maybe its in the wiring harness?? anyone encounter this? thanks

chinaman

Man, I'm and idiot I swear, i just got done typing this, went to go sit on the couch and I got to thinking, wait an minute you gotta do that whole turn the screw thing twice I think....came on here checked to make sure my thinking was right and it was
Sorry to have wasted your time by reading 2 of my posts, I think it was just a minor brain malfunction thinking I only had to do it once

Long story short the code is gone