07 Chevy Tahoe not starting

[Bowtie4Life]

I've run into a tricky situation. I clean out the throttle body on the Tahoe and after I put everything back together the car would not start. It's an 07 with a 5.3L. The fuel pump primes and I have pressure, battery is good, I can bump the starter manually so it's not security related. The car won't crank over at all, the remote won't work, the doors locks don't work either.

I talked to a buddy of mine that is a locksmith and he is stumped as well. He told me to cycle the key for 10 minutes 3 times to reset the security. Problem is the security light does not turn on. The gauges don't move right, the interior lights don't work but the dash lights up when you turn the key on. All fuses are good, all relays are working. I'm just stumpt, any suggestions?

 

[rockenthebowtie]

Hey bowtie this is a tricky one but just for future reference even if it was a security system issue you would still be able to bump the starter manually the security system will diable the starter from the ignition switch creating a no crank no start condition but you can still manually apply 12 volts to the starter solenoid and it will crank but the security system will also shut off the fuel injectors keeping the vehicle from starting... now taking into consideration that all was performed was a throttle body system service and there were no accidental created problems... common failure for your symptoms are either a bad battery ground cable dont try to clean or repair needs replacing if thats the failure of course or a internally shorted Body control module..my guess is that it maybe the body control module since you say your still able to manually get the starter to turn over if it was a ground cable failure it wouldnt do anything even when doing it manually. .. However being that its obviously an electrical problem there are many variables and factors involved that can cause the no crank no.start condition.. so proper diagnostic equipment will be necessary to pin point and resolve your issue. Hope this helps. . Good luck to you my fellow bowtie keep on rocken it lol

 

[Bowtie4Life]

I did disconnect the negative prior to service. The fuel pump is priming to the fuel rail, I'm getting 60 psi as I turn on the ignition but the ignition system seems to be disabled. I'm narrowing it down to the security system, maybe the key lost connection with the ignition. It's odd how the door locks don't work, keyless entry doesn't work, no dome lights, dash takes a bit to actually function or the BCM. The only odd thing is that the windows are also controlled by the BCM and they work fine. I have a few friends that are locksmiths and that are stumped as well because they said if it was a security issue the security light would stay lit which isn't the case. They walked me through resetting the security but having no luck. I appreciate the advice though, seems like I may have to get it into the dealership.

 

[rockenthebowtie]

Let me ask you this... does it have a aftermarket alarm by chance ? .. also the BCM has various diodes and integral circutes that will still allow for some of the BCM controlled systems to work just as the door locks and dome lights dont and the wwindows do. as for your friends they are right the pass lock icon on the IPC would be illuminated along with a service theft system messege on DIC... again look for a afteraftermarket alarm and or even a dealer installed kill switch and if shorted out and is tapped into the BCMs circuitry it can knock out those functions.. dealers install these to prevent vehicle theft from the dealership lot.. if it does have one for the most part it will be mounted right there on the trim panel below the steering wheel

 

[Bowtie4Life]

No, no aftermarket alarm. We bought it new, it's her car. I know that there are no aftermarket alarms or kill switches installed. Dealer has performed all her oil changes, I have done all other repairs to it. Just odd on how the BCM failed. I'm trying to figure out if maybe because I moved the flapper of the throttle body if maybe it sent some type of signal back to the system. I was just reset the TPS afterwards. The radio works, the dash is slow at first but functions, the windows work. No power locks, no remote, no dome light. After doing more research it's really pinpointing to the BCM. Now I just have to see if the system can be reflashed or replaced. It's functions are 50/50 and prior to this we never had any problems with it.

 

[rockenthebowtie]

Its highly impossible that it was anything you did the TAC (throttle acutuated control) and BCM circuitry are on 2 totally different wiring harnesses the only circuits that it will have are GM LAN high and low speeds class 2 serial data communication circuits but those are between the PCM and BCM not directly from the TAC to the BCM .. chances are is that it was already on its way out and by disconnecting the negative side battery cable just finished it off.. trust me when I tell you that this is a common problem and or failure look at it this way good thing it happened when it did and not when she was out and about leaving her stranded who knows where

 

[Bowtie4Life]

Well I sure do appreciate your input. It left me stumped cause I've always taken care of the things on her car and kept going back on everything I did second guessing myself. I'm very particular on how I do things. I guess it it was meant to be and the BCM was on it's way out then nothing would have prevented it anyway. I'll give you an update after I take it in tomorrow to confirm it all but once again, I appreciate the help.

 

[rockenthebowtie]

Hey no problem glad I can help and shed some light on your dilemma I'm just hoping she wasn't giving you to much of an ear full lol.. but yea keep me posted hope it all ends well

 

[Bowtie4Life]

You know the old saying, "No good deed goes unpunished." Well that's me right now. I split with her a while back and she called me asking her to help her cause her car failed smog. I ran the codes and pin pointed the problem and told her no problem. I won't take long to take care of it. Low and behold this happens, do you think that maybe I've gotten a little bit of an ear full. My friends were giving me a hard time and telling me, that's why you don't help out. Who do you think is gonna have to pay for the repairs because in her eyes it worked before I got a hold of it, lol. I'll keep you posted though, thanks again.

 

[rockenthebowtie]

LMAO!!! Sorry to hear that my fellow bowtie brutha..The " No Good Deed Goes Unpunished " cliché from what I cant help but in vision is a complete understatement.. oh my I do I feel your pain..its a double whammy not only because of your emotional state but your wallet too.. OUCH !!! I was going to end it with LOL but I cant its still just way way to soon.. what a man will do to sink himself in to some fish taco...lol.. so im guessin it had throttle body codes..

 

[Bowtie4Life]

Oh don't get me wrong I'm done with her. She is the mother of my kids and since the split things haven't gone her way. I was just trying to help me because she does need the car to take the kids around when they aren't with me. I'm in another relationship and not looking at taking a step backwards. I can't go another round having to pay the attorneys. She failed smog and didn't know what to do. I told her why did you even let them smog it with the the check engine light on. It was gonna fail regardless. I ran a scanner and pulled P0121 for her TPS sensor. Don't get me wrong sensors go out but majority of the time something else lead up to it. The scanner showed the throttle was open 27% so I figured it needed a cleaning since she doesn't really take care of the car besides oil changes. After I took the air intake system off, her throttle body was black on both sides and pretty caked on. I sprayed it with cleaner but wasn't enough, it was thick. I finally cleaned it all up, wiped down the intake and used my pistol vacuum. Cleaned the air tubing and cleaned the MAF screen. Put it all back together, installed the negative back on and that's where the problem started. I even told her last night that everyone told me to leave it up to her to handle it. LIke she said, you have always taken care of all the cars and motorcycles and that she didn't think it would be anything major. She just doesn't trust the shops. My oh my, lucky me huh.

 

[rockenthebowtie]

I hear you man gotta do what you gotta do when it comes to kids I have 3 myself... I gotta say and im sure many will agree with your approach to start with the cleaning of the throttle body theres actually a TSB to do just that with that DTC.. you also mentioned you were also going to perform the idle relearn do you have a scan tool to do that with ? Also one more thing and really hate to even mention it because of what your going thru already but ive seen extream cases like you said how the TB was caked the idle relearn wont do it the idle will sticks up and will not come down. . you may want to have them reprogram the latest GM software updates to the PCM since its there so you can be sure the idle will be ok..just to save you from some more potential greif

 

[Bowtie4Life]

I don't have the software for that I was just going do it by disconnecting the battery and turning the ignition on to try and learn with my fingers crossed. It works sometimes but not always. If not try and drive it for a while to see if it relearns itself. I know that there are a few things that can be cheated on but not everything. I was already planning on asking the dealer now since I can't get the car fired up to see about checking it or setting it while it's there since I can't tinker with it for a while and she needs her car back. Believe me when I tell you I'm preparing for the potential grief. This is why I prefer to just do my own stuff.

 

[Bowtie4Life]

I also appreciate the added info. I did look up the relearn and the process if close to the TSB. I didn't know that they had one out but will look it up and see if I could find a specific on for her car. Not sure how much longer she is gonna keep it but that's on her. It has 99K on it and it's the longest she has had one car. We would replace hers every 3 1/2 years but that's on her now. I only tinker with cars here and there, more old school than new. I work on semi trucks a lot more than I do cars and believe it or not they are simpler. Damn emissions are screwing everything up though. Things have gotten a lot more sensitive than they used to be.

 

[Bowtie4Life]

Well it was the BCM. The unit was tested but found to be bad. The unit was replaced and the didn't flash the PCM but did do a TPS relearn after I told them what I had done to begin with. Only issue I have now is that the remote and power locks only work on the front doors and tailgate. They said that the BCM has nothing to do with the doorlocks. That the BCM is only a program and that the actuator probably went out. I'm stumped on that as well as I know that they worked before I disconnected the battery and what is the odd of both going out at the same time. Doesn't make sense, but her check engine light is out. I told her to run it for 50 miles or an hour to make sure the codes don't come back and that I can scan it real quick before she takes it in just to make sure but she should be fine and ready for her smog test now.

 

[rockenthebowtie]

Well its good to hear that you got her back on the road. . Good advice on having her driving it the 50 mile that will trip all the emission monitors to make sure all systems are operating property. . Yea thats to bad about the rear door lock actuators unfortunately thats another common failure on those GM suv/trucks very common not hard to replace but with the way your luck has been going nothings looks like its for you.. if you change those out you may end up with 4 flat tires lol..