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01 silverado knock sensor ?

Discussion in 'Truck & Equipment Repair' started by elegantlawns, Jan 2, 2013.

  1. elegantlawns

    elegantlawns Junior Member
    from Mi
    Messages: 25

    I just had my 2001 Silverado 1500 in the shop for the intake manifold gaskets to be repaired when I got it home a few days later the engine light came on so I had it put on the scanner and it came back knock sensor my question is should I hold the repair shop liable for fixing the issue? ive done some research and found out that these two things seem to go hand in hand with one another. I just wanted to see what you guys think. thanks.
     
  2. plowin-fire

    plowin-fire Senior Member
    Messages: 196

    There are two knock sensors under the intake. Most of the time water gets underneath there and corrodes the connectors and wrecks the knock sensors. So either it happened to fail a few days later, or they didn't plug in the connector on the back left side of the intake. Should be a two wire connectors with blue wires headed back. Unplug the connector and check the resistance on each wire towards the sensors. The other lead of your meter should be grounded. If there in an open, the sensors are bad or poor connection underneath. Resistance should be 93 to 107k ohms.
     
  3. elegantlawns

    elegantlawns Junior Member
    from Mi
    Messages: 25

    OK thanks for the info very informative.
     
  4. hatefulmechanic

    hatefulmechanic Senior Member
    Messages: 228

    Every one that comes through my doors getting an intake gasket gets knock sensors unless the customer declines.

    But there is a decent chance the connector is not seated fully.
     
  5. elegantlawns

    elegantlawns Junior Member
    from Mi
    Messages: 25

    so iam correct when i say that the repair shop should be held accountable? cause iam not wanting to pay for it to be tore down to the intake again, however i would pay for the parts. is this unreasonable?
     
  6. hatefulmechanic

    hatefulmechanic Senior Member
    Messages: 228

    Not always. As a shop owner, if a problem arises after a repair, the first step I take is to determine what is needed to fix it. If the sensor itself is failed, unless we can see obvious damage to it, it's an inevitable failure.

    Crap happens, and its in everyones best interest to work together to get the truck fixed. Call them, ask to look at it, and see if it is a connection issue or an actual bad sensor.

    Sadly a lot of shops could give a damn about customer relations, but going in complaining and demanding they fix it typically will not solve anything.
     
  7. elegantlawns

    elegantlawns Junior Member
    from Mi
    Messages: 25

    ok, thanks for the advice.
     
  8. GSS LLC

    GSS LLC Senior Member
    Messages: 639

    Some shops forget to undo the wire guides and rip the wire apart
     
  9. elegantlawns

    elegantlawns Junior Member
    from Mi
    Messages: 25

    hmmm also very informative. thanks.
     
  10. theholycow

    theholycow PlowSite.com Addict
    Messages: 1,180

    It is a very common failure on these trucks. There's even a TSB about it that says to build a dam of silicone to prevent water from corroding the sensors and replace the sensors. IIRC people also recommend replacing that part of the harness.

    If the shop knew these trucks well then they would have recommended replacing the sensors while it's apart, just like hatefulmechanic said...but I wouldn't say you should completely fault them for it. Since it was just in for most of the same job it should come apart quickly, cleanly, and without further risk, so they might be willing to do it at a discount.
     
  11. gottaloveOT

    gottaloveOT Senior Member
    Messages: 115

    If it wasn't throwing a light before you took it in, and it took a couple days before it came on after the repair, unless they didn't seat the connector all the way I would say you are liable for the repair costs.

    The part obviously wasn't causing a problem before you took it in and it wasn't bad when you picked it up and the sensors are not "officially" part of the intake repair so to hold them accountable for something that is coincidental won't fly in their eyes.

    As stated above if they are a good shop and good customer service is what they are about, they will work with you to figure out if something they did caused the problem or if the sensor just failed and then go from there. But I wouldn't get my hopes up.
     
  12. elegantlawns

    elegantlawns Junior Member
    from Mi
    Messages: 25

    ya, I understand what you mean. what iam saying is from what ive looked up that when the intake manifold gaskets go bad they usually cause the knock sensors to go bad as well so my thought is that if the shop was good enough they should have known to deal with this problem as well?
     
  13. theholycow

    theholycow PlowSite.com Addict
    Messages: 1,180

    The trouble with that is they're damned if they do and damned if they don't. If they recommend stuff like that as a matter of course based on that logic all the time, they risk a reputation as a needlessly upselling scammer. If they don't (as they didn't), they risk a reputation as hacks. Now, if they knew these trucks really well, as a specialist or enthusiast would, they'd have known that it's pretty much a sure thing...but if they're general purpose mechanics working on all makes and models then there's no way for them to know that kind of stuff about everything.

    Most business owners/managers don't want dissatisfied customers. Most of the time when dissatisfaction happens it's a conflict like that. It's hard for the customer to identify with that a lot of the time but I try.
     
  14. elegantlawns

    elegantlawns Junior Member
    from Mi
    Messages: 25

    the Guy that did the work owns a Chevy truck and its him and a helper.
     
  15. theholycow

    theholycow PlowSite.com Addict
    Messages: 1,180

    Well, put it this way: I can't imagine that he wouldn't want the opportunity to sell you more work if he knew it was appropriate. He may have never had that problem with his...my truck hasn't, I just know about it from reading GM forums. Your truck is 10 years old and you've never had that problem before.

    Granted, he could just be an idiot. That's possible too.