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Discussion Starter · #1 ·
I have a 2004 extended cab 2 wheel drive. In 2012 I changed my battery, and my check engine light came on. The code was for a Knock Sensor. It went away soon after with no work done. Last year around winter, the dashboard started turning on and off while driving. I'm in need of inspection next month so I go to the dealership and have them run a full diagnostic with the main problem being dashboard and check engine light. They tell me the check engine was because of an EVAP (spelling?) sensor and the dashboard needed a cluster replacement. I agreed for them to swap the two. I get a call telling me it's ready to pick up, and the battery died (dead cell), so I had to bring a new one.

I pick it up 6 days after it entered the shop, swap the battery, and driving it off the lot, not even a mile, the speedometer gauge stops working and the check engine light is back on. They take it back to install a new cluster after having to order one, and this time the check engine light is for the Knock Sensor. The dealership told me a battery with low voltage could trigger it so he removed the check engine light (I don't know how), and as of yesterday, I had my truck back, the dashboard working, no check engine light. I drive it ~50 miles and the check engine light came on again for the Knock Sensor.

I've been quoted at $750 for fixing it, but I've already spent 33% of my blue book value on this truck and I don't want to pay to fix it then another one comes up right after.

What suggestions do you have on how to proceed with this? Should I could call the dealership and tell them "what the hell, I just got it from you and the check engine light came on again. I put it in the shop to fix the engine light, I've payed a lot of money, just to have it happen within 5 hours of leaving the dealership again"
 

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"what the hell, I just got it from you and the check engine light came on again. I put it in the shop to fix the engine light, I've payed a lot of money, just to have it happen within 5 hours of leaving the dealership again"[/QUOTE]

Exactly!!!


I hate it, but I can see it happening with the history you presented, heck pay for the part if you have to. But get them to own it, not expecting it after knowing it was a prob in the past. IMO
 

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Discussion Starter · #3 ·
I'm waiting on a call back from the main technician no. I've been in and out of that place for 3 weeks now, I'm on a first name basis with a few of them purely through my time there.
 

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If they fixed the evap issue and replaced the cluster then, sorry to say, you don't have a leg to stand on with the knock sensor issue. That is completely unrelated to your evap system issue and you cluster issue. I don't even want to know what they charged you to fix those things. If you came here first we could have had your cluster repaired for under $150 and guided you on how to fix the evap issue for under $100. You said the knock sensor has tripped the light in the past. They are a known issue with these motors. But again, it is Not related to your other issues. Look at it this way. If a customer brought me their car for a tie rod replacement and then called me the next day and told me that they had a coolant leak now and that I should fix it for free because I just fixed their tIe rod, I would just laugh. They are in no way dependent on each other. Dealers charge upwards of $100 an hour labor plus inflated parts prices. Take it to a local shop and I bet the price would almost be cut in half. If the knock sensor code was not present when they scanned it then they don't know that there is an issue with them
 

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Discussion Starter · #5 ·
I wanted to trust the dealership for the diagnostic ($100) and gave them a long list (even cosmetic crap that wasn't important but I wanted a quote). The mechanic I frequent graduated with my dad from high school and we've done business there forever with 6 of our family vehicles and has always given us great service to our knowledge. And not to make you vomit, EVAP was $400 and cluster was $575.

But I wanted to clarify that knock sensor had nothing to do with the other errors so I can explore it on my own. I don't trust myself in reassembly for the knock sensor. I've never had any issue or light for 10 years, and then I had the dashboard, EVAP, and now Knock Sensor. So I don't hate my truck, it drives like a champ and I don't drive very much. I've rode my bike to work for 7 years. I use it on the weekend to visit family. I'd estimate I drive less than 10,000 miles a year. I just need to get it inspected and this light is obviously an issue so I'm seeking peace of mind that the knock sensor will fix the damn thing.
 

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If they fixed the evap issue and replaced the cluster then, sorry to say, you don't have a leg to stand on with the knock sensor issue. That is completely unrelated to your evap system issue and you cluster issue. I don't even want to know what they charged you to fix those things. If you came here first we could have had your cluster repaired for under $150 and guided you on how to fix the evap issue for under $100. You said the knock sensor has tripped the light in the past. They are a known issue with these motors. But again, it is Not related to your other issues. Look at it this way. If a customer brought me their car for a tie rod replacement and then called me the next day and told me that they had a coolant leak now and that I should fix it for free because I just fixed their tIe rod, I would just laugh. They are in no way dependent on each other. Dealers charge upwards of $100 an hour labor plus inflated parts prices. Take it to a local shop and I bet the price would almost be cut in half. If the knock sensor code was not present when they scanned it then they don't know that there is an issue with them
Ok, I'm sorry on both sides of this, one for thinking you had taken it in and they knew about the knock sensor,
Along with your list. The other for suggesting you should be able to get this taken care of if you both did a little give and take since I assumed both new about the sensor prior. Excuse me if I assumed to much.
 

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If this is like my 2002 5.3L and has the knock sensors on the top of the engine under the manifold then do what Pikey says. Also, seal the knock sensor rubber covers with some RTV around the outside to prevent water in the knock sensor cavity. Had to do this on mine.
 

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first thing is the 2003/4 vehicles have defective dash clusters made by GM defective crap.. all these fail and if the dealership fixes this is more crap.

clusters are fixed on internet sites that replace all these with good units... also cheap and you can drive with it removed.

next is the infamous KS codes this is from washing the engine. what happens is again defective GM crap.. GM used a foam to seal the upper intake manifold .. this causes water to enter from the front of the intake and get trapped under where the 2 KS sensors are mounted in depressions which hold the water and eat at the wiring connections then the codes..........

replacing the 2 sensors covering the sensors with some sealant to protect.. then when installing the upper intake seal the front opening with sealer lots of sealer leave the back open [rear ]... this allows anything to escape out and is down much lower than the front..

again never wash engine not good !!!
 

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first thing is the 2003/4 vehicles have defective dash clusters made by GM defective crap.. all these fail and if the dealership fixes this is more crap.

clusters are fixed on internet sites that replace all these with good units... also cheap and you can drive with it removed.

next is the infamous KS codes this is from washing the engine. what happens is again defective GM crap.. GM used a foam to seal the upper intake manifold .. this causes water to enter from the front of the intake and get trapped under where the 2 KS sensors are mounted in depressions which hold the water and eat at the wiring connections then the codes..........

replacing the 2 sensors covering the sensors with some sealant to protect.. then when installing the upper intake seal the front opening with sealer lots of sealer leave the back open [rear ]... this allows anything to escape out and is down much lower than the front..

again never wash engine not good !!!

maybe GM customer service can get you cash back ?

just kidding !!!!
 

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JCat, just to verify, after replacing the knock sensors we should be taking silicone sealant and using it to seal up the upper intake manifold by the front of the engine up by the alternator or by the firewall ?

And also is clear silicone good enough to seal with? I was h0ping to go with a clear silicone or maybe black if they make it so that it matches the engine. I was thinking of using a caulking gun so i could get a nice copious, but even layer. Rather than buying 2-3 RTV silicone tubes and trying to seal it like that.



just wanted to clarify for my own personal understanding.

Thx,
 

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the sealant to use would be the type that is safe for your O2 sensors. it is possible silicone could vaporize and get into the intake which is not good for these O2 sensors. I used a sealant made by dow corning #795 black and this is used in the glass/steel construction world. the auto stores should have some sealant that is safe to use on engines to seal these type conditions. you should only need 2 tubes at the most 10 oz...approx..

sealing the front is what should be done not firewall end...of the upper intake...this is in a GM TSB which instructs how to do this..the firewall end is much ower so any leaks will drain out, and the KS sensor will have sealant covering them so there will be no repeat...
 

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Thanks JCat i was aware of the TSB regarding sealing the knock sensor coverings but it did not mention sealing the front of the intake manifold in that particular TSB. Thanks for the advice, also I would be willing to go out of my way to find the exact sealant "Dow corning #795" you used just to be sure i found a sensor safe, black sealant that is precisely what i desire on to use on my truck. Did this come in a cylindrical tube large enough to put in a caulk gun?
 
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