knock sensor failing my emissions test?
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From: Northern Virginia
knock sensor failing my emissions test? I have gone to advance and barrowed thier actron scanner. I ckecked the readiness codes and all was fine. Actually I checked EVERYTHING and all was fine except for "knock sensor 1 bank 1 voltage low". I reset the codes and the light goes out for a short while. If I reset it and start the car, it useually stays out for 15 minutes or so. I cleared the codes just before emission check but I am not even allowed to even try a test. I had the car fully warmed up but the machine says the following.........
not ready:
catalyst
evaporative system
sec air system
O2 sensor
H02 sensor
EGR system
Unsupported:
Heated Catalyst
A/C System
So, would a faulty bank one sensor do this or is there more underlying issues?
not ready:
catalyst
evaporative system
sec air system
O2 sensor
H02 sensor
EGR system
Unsupported:
Heated Catalyst
A/C System
So, would a faulty bank one sensor do this or is there more underlying issues?
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Well, crap! I didnt unplug the battery so I never thought just clearing the codes would have been an issue like that, although it WAS in the back of my mind. I asked the inspector if that would have done it, but, he was asian and kep saying "fix problem first, fix problem first!". Not that there is anything wrong with Asians, I dated one great chick that was Asian, but, the language barrier was way to thick, so, I had to just leave in confusion and frustration that I waited in line for nothing, lol.
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Well, he actually said "fix problem first" in very plain, consise english, but, after that, we just kind of looked at each other like two deer caught in each others headlights. I said okay thanks, and took off. `I have had the car on the road for about 150 miles, but, I would have also thought that the computer would have been reading everything by then and if anything, just report that the knock sensor was bad. I would not have thought it clearing the codes would have reset the whold darn computer!?!?!?!? 
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Some states will let you get away with a couple "not readies." Try a couple GM drive cycles too, supposed to help even if you don't follow it to the letter. www.obdii.com/drivecycle.html
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Thanks, I will definitly copy that page for when I go the second round. Thing is, until I fix the knock sensor, I dont think he will hook it up to the machine as the check engine light will then be on after I do all that, and, if what I am understanding, clearing the codes will make me have to start all over again. Gots me a dog chasing his tail syndrom until I change out the knock sensor, or, make sure the wiring is not cut.
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From: Northern Virginia
thanks 2001, yea, I saw that on my 98 when I had it apart. I am hoping the cap part of the wiring harness popped off or something, but, if they are on good and tight and the wiring checks out, i will be sure t change them both, thats for sure.
Originally Posted by csmc711
Well, crap! I didnt unplug the battery so I never thought just clearing the codes would have been an issue like that, although it WAS in the back of my mind. I asked the inspector if that would have done it, but, he was asian and kep saying "fix problem first, fix problem first!". Not that there is anything wrong with Asians, I dated one great chick that was Asian, but, the language barrier was way to thick, so, I had to just leave in confusion and frustration that I waited in line for nothing, lol.
When knock sensors show low voltage its usually a short from moisture. When the sensor shorts out it usually damages the knock sensor harness too. Its not a hard fix but I replace both knock sensors, and the harness and then use RTV silicone and seal off the sensors from any possible moisture. Ive done a few like this and they never had an issue again. The first one i did was 3 years ago on a 98 and still going strong.
You can replace the sensors like i did on his car a few times and then you figure out the harness has been shorted as well. WHen i replaced the harness after both sensors were replaced we never had another problem. Its some kind of resistance in the harness that the sensors cant operate correctly on and will throw that code of low voltage.
Yeah you are right.... Since they are very low-voltage units to begin with, it takes VERY little resistance in the cabling to cause a voltage drop. V=I*R ..... the current is TINY so a minor change in the R component will be readily seen in V.
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Okay, well, had to get a pigtail sensor connector from the dealer. I cut 10" off the old harness and soldered, siliconed and then shrink wraped the wires together, siliconed the caps on and a little dab for good measure around the wiring that pops out the middle of the cap. Got her all together, drove her around for an hour tonight and everything seems fine, no check engine light.
Now I guess it is time for 2001's drive cycle, bwhaahahahahahahahahaha!!!!
Now I guess it is time for 2001's drive cycle, bwhaahahahahahahahahaha!!!!
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As far as my dealer was concerned, there was no connector in his records, just pig tail connectors in which you splice into the existing harness with. Came with about a foot or so of wire.
Originally Posted by csmc711
Okay, well, had to get a pigtail sensor connector from the dealer. I cut 10" off the old harness and soldered, siliconed and then shrink wraped the wires together, siliconed the caps on and a little dab for good measure around the wiring that pops out the middle of the cap. Got her all together, drove her around for an hour tonight and everything seems fine, no check engine light.
Now I guess it is time for 2001's drive cycle, bwhaahahahahahahahahaha!!!!
Now I guess it is time for 2001's drive cycle, bwhaahahahahahahahahaha!!!!
Originally Posted by csmc711
As far as my dealer was concerned, there was no connector in his records, just pig tail connectors in which you splice into the existing harness with. Came with about a foot or so of wire.
Ill post the number tonight when I get home.