CHEVY EXPRESS NO CRANK NO START DIAGNOSIS & FIX

[Music] hey guys what's up it's eric with advanced love automotive welcome back to the channel today we're here checking out this work van it's a 2007 chevy express fan 2500 and it's got the 4.8 liter v8 engine customer complaint is that the vehicle is a no crank no start now this is a company vehicle and the back story to this one is that they initially lost the key a few months ago and i guess they had other vans that they used so this one kind of just sat for a few months they finally had somebody come and make the key and when they tried to start it up it didn't want to start so anyways you guys know how we do it let's go ahead and get started okay so taking you guys over to the vehicle now the first thing that i noticed is that the battery was completely dead so i've got my jump pack on here let me take you guys inside and show you what it's doing all right so i've got the key in my hand here now i'm going to go ahead and stick it into the ignition turn the ignition on so you guys can see everything powers up and the first thing i like to look for is always going to be a check engine light on the instrument cluster you guys can see the check engine light is illuminated now i'm going to go ahead and attempt to crank this thing and you guys are going to see that it does not want to crank at all so here we go try that one more time now i will say that whenever i cycle the key like this i can hear the fuel pump priming so we definitely know that it's getting fuel up to the engine again i'm going to go ahead and attempt to crank it and we got nothing now the other thing that i like to look for is some type of security or anti-theft warning as you guys can see we don't have any of that and on top of that this key is actually just a regular key it doesn't have any type of chip on it so i don't think this van has any type of security system so i know what a lot of you guys are thinking and i'm kind of thinking the same thing we might have a bad starter i mean it makes sense the truck has been sitting for a while you know we might even be able to get up underneath the truck and maybe tap the starter with the wrench or something see if we can get this thing to turn over but of course before we decide to call the customer and tell them that we need to replace a starter we need to do our proper diagnosis first we need to make sure that we don't have a problem with a bad relay or a bad fuse a bad computer or maybe even bad wiring now as far as what our next step should be i mean there's a lot of different places we can start but what i want to do first is i want to go ahead and take a quick look at the starter relay all right guys so taking a quick look under the hood let me show you guys where the fuse box is located and the starter relay now the first thing i noticed when i saw this relay or fuse box is that it didn't have a lid on it and as you can tell that's definitely not a good thing because it's pretty obvious that we had some type of water intrusion going on here because we seem to have quite a bit of corrosion going on here now i don't know if this is going to affect the function of the starting system but i mean it is a possibility anyway i've already gone ahead and located the starter relay it's this one right here the first thing i'm going to do is i'm going to try to pull it out sometimes these things can be pretty difficult to get out there we go man take a look at that we got some corrosion going on here looks like we've got some oxidation from possible water intrusion now again i'm not sure if this is affecting the starting system but you guys could imagine that you know it's possible that we have maybe a contact issue or something from this corrosion and that's what's causing our problem in the starting circuit let's take a quick look inside of the fuse box where the relay was located you guys can see we have a little bit of corrosion not too much so i'm not really sure what to think but i guess what i want to do first is to start by putting in a relay jumper and seeing if we can test the circuit from here okay guys so what i have here is my relay tester kit now you've probably seen me use this in plenty of other videos that i have if you guys are looking for a kit like this you can find a link in the description to where you can purchase this so we've got the relay here and i've already found the adapter it's gonna be this green one you guys can see it's a four pin adapter so we're gonna go ahead and stick this into the slot and this is gonna give us a central point from where we can test the entire circuit okay guys so before we go any further i want to take a quick moment to go over the wiring diagram with you just so that you can understand what it is i'm looking for when i do my pinpoint checking so what we're looking at here is going to be the wiring diagram for the starting circuit it's actually pretty simple to follow so let's go ahead and start by identifying the components right up here you'll find the starter relay this box right here and then if you look at this dotted line the outer box represents the underhood fuse box if you look down here you'll see this is a starter motor down here this is the powertrain control module over here we have the park neutral safety switch here we have the fuse box again and then right over here we have the ignition switch so what i want to do is i want to focus on the starter relay because this really is the central point in which we can test the entire system now if you guys understand how relays work you'll know that the relays have two sides one side is going to be the control side and the other side is going to be the load side or the switching side now with your typical four pin relay you're going to have two powers one power for the switching side and one power for the control side so what i want to do is back trace these through the wiring diagram and figure out where they come from starting here on the load side i'm going to highlight this and then we're going to zoom in as you guys can see this pin here at the relay gets its power from this ignition a fuse number 49 which is a 40 amp fuse and if we highlight this red wire you can see that it comes from the positive battery terminal so right here is the battery and you can see right here it says positive that's the positive battery terminal so that is going to be a direct power from the battery so that means whenever we go to this relay and check the power here this is going to be a power at all times it doesn't matter whether the ignition is on or off now moving over to the control side i'm going to highlight this here we're going to follow it out and you guys can see it comes out on this dark green wire then it goes to the park neutral safety switch now if you guys take a look inside of the park neutral safety switch you can see that depending on what position the switch is in it's either going to allow the current to flow or not and if you look at the way this diagram is drawn up you can see that it's either in the park position or the neutral position which is allowing the current to flow so we're going to follow this back out and you can see this pink wire we're going to highlight it and if you follow it over you can see that it goes back to the underhood fuse box and it goes through this uh engine fuse number one which is fuse number 23 and it is a 15 amp fuse so i'm going to highlight the output here and we're going to follow it up and you can see that it comes from the ignition switch now if you look inside the ignition switch you can see that in order for there to be current flow through this pink wire the ignition switch has to be in the run or the start position when the ignition switch is in the run or the start position that's going to close the switch here and allow the current flow to come through this red wire here and if we follow it up you can see that it comes from this ignition b fuse number 52 which is a 40 amp fuse and if you follow it up here on the diagram it says that it's hot at all times now even though the source here is a power all the time you have to understand that that power will not get to the control side of this relay until the ignition switch is in the run or the start position and the neutral safety switch is in either the park or the neutral position so now that we understand where the power source for these two pins come from we can focus on these two pins down here we'll start with the control side i'm going to highlight the output here you can see it's a yellow and black wire and if we follow it down you'll see that it goes directly to the pcm and the way this works is whenever the pcm wants to engage the starter it's going to ground the circuit when it grounds the circuit if we follow this back up here that's going to energize the coil winding inside of this relay it is going to magnetize which is going to close the switch here and that's going to allow power to flow from this fuse 49 through this purple wire now if we follow this purple wire down you'll see that it goes directly to the starter solenoid now if you look at the starter solenoid you'll see that inside of the solenoid we have magnetic coil windings as well and you can see that it actually grounds to itself so as soon as we send a power into the solenoid that's going to energize these coil windings that's going to magnetize this which in turn is going to close the switch on this side when the switch closes that's going to allow power to come from this black wire which if we follow it back up here you'll see that it comes directly from the battery positive so power from the battery positive is going to flow through this black wire and directly to the starter motor and as you can see here the starter motor actually grounds to itself so if you guys ever take a look at the back of a starter motor you'll see that you have two main connections one of them is going to be for the starter solenoid this is going to be a thinner low current wire and then you'll have this bigger battery cable which is going to be the main power feed the feed starter motor so now that we understand how the system works we can move back over to the vehicle and do all of our diagnostic checks at the starter relay again we're going to be looking for our two power feeds one for the switching side which is going to be a power at all times the other power here at the control side which is going to be a power only when the ignition switch is on and the neutral safety switch is in either the park or the neutral position then we can come down here to this pin we can check to see if our computer is actually grounding the circuit and trying to engage the starter then finally we can move over to this pin here and check our output from the relay that goes to the starter solenoid so with that being said let's go ahead and move back to the vehicle so i'm gonna go ahead and stick it into the slot here there we go so i've got my power probe here it is connected to the battery as you guys can see and what we're gonna do is we're going to touch this relay and we're going to try to figure out which pin is for what now according to the wiring diagram we should have two powers one for the control side and one for the switching side but the important thing to note is that the power for the switching side is going to be a power at all times so even with the key out of the ignition we should have power on one of those pins and as far as the power for the control side well that power is only going to show up with the ignition in the run or the start position so as of right now the key is not in the ignition so we should only have one power source so i'm gonna go ahead and try to locate that one by touching each of these pins so i'm gonna start by touching this pin you can see we have nothing there i'm gonna touch the pin next to it you guys can see we're showing the ground on that one i'm gonna touch the pin down here you can see i got nothing there zero volts now i'm going to touch this last pin down here at the bottom you can see we have our battery power feed on this pin down here so what i want to do next is i want to go ahead and stick the key into the ignition and turn it to the run position so i've got the key right here i'm going to go ahead and stick it into the ignition and turn it on now we can move back to the relay and try to identify which pin is our other power let's see here we'll start by touching this pin and you guys can see we have our battery power on this pin let me go ahead and check the other ones see we got nothing there and i'll touch the other one here and you can see we have a ground here so it looks like we have our two powers this one down here is going to be our main battery power feed which is a power all the time and then this one up here is going to be our ignition power feed which is a power whenever we turn the ignition on now the other really important thing that this tells us is that the neutral safety switch is not a problem because in fact if you take a look at the wiring diagram you'll see that this ignition power source has to travel through the neutral safety switch in order to reach this pin here so just the fact that we have power on this pin here tells us that we don't have a problem with the neutral safety switch next up we're going to try to identify the other two pins one pin should be the control for the engine computer and the other one should be the pin that goes directly to the starter solenoid now just by touching these two pins i already have a pretty good idea of which one is which because if you guys notice that when i touch this pin up here you'll see that we have zero volts but when i touch this pin down here we have a ground now the reason we're showing a ground is because this power probe is finding a ground through the starter solenoid now the other quick way that we can prove that this pin up here is for the computer control is by sticking the relay in when we stick the relay into the top of this adapter the power should flow through the control side of the relay from this pin here which is our ignition power feed and it should come out on this other side of the control side that goes to the computer again as you can see this pin over here does not have any power but watch what happens whenever we stick the relay in there here we go i'm going to go ahead and stick the relay into the top now as long as we don't have a problem with the control side of the relay we should have power on this pin here as you guys can see that's exactly what we're showing so we know for a fact now that this pin right here is the control wire that goes to the engine computer and whenever the engine computer wants to crank the starter it's going to ground this pin here when it grounds this pin here that's going to energize the relay and it's going to send a power output on this pin over here again you guys can see this pin is a ground at the moment because it's finding its path to ground through the starter solenoid so what i want to do real quick is i want to take this little wire with this terminal end that came inside of the kit and i want to attach it to the control side of the relay like so then we're going to take the tip of the power probe and stick it into this end okay so i'm going to go ahead and connect the two now what i'm gonna do is i'm gonna move inside the vehicle and i'm gonna attempt to crank the engine over and what you should see is that this turns into a ground now the nice thing about this power probe and i know it might sound annoying on the camera is this beeping noise but what's convenient about it is that the beeping noise actually changes tone whenever it detects the ground this is helpful because when i'm inside the vehicle cranking it i can't actually see the meter on the power probe but i can hear the tone change so i just went ahead and set the camera down i'm gonna go ahead and move inside the vehicle and crank this thing over okay guys so i didn't even have to see it i could hear the tone change so we know for a fact that the engine computer is trying to ground this relay what we need to figure out is whether or not we have an output from this relay going to the starter solenoid so as you guys can see i switched the lead over to this pin right here which is the output that goes to the starter solenoid now i'm gonna go ahead and stick the tip of the power probe into here okay as you guys can see i have the power probe connected to the lead here and i'm pretty much gonna go ahead and do the same thing i'm gonna attempt to crank the engine over and what you should see is that this switch is from a ground to a power well there you have it guys proof that the relay is working and everything else in the system is working so we need to go ahead and attack the starter motor all right guys let me take you over to the passenger side fender well because in here we can actually get a good look of the starter motor all right so hopefully you guys are getting a good view of the starter so this down here is a starter motor and this is a starter solenoid as you can see this is the main battery cable that's attached to the starter and if you look up here you'll see the cable that goes to the starter solenoid now what we could try to do while we're here is just take something like this and try to tap the starter body and maybe even the solenoid body to see if we can get the starter to unstick but i'll tell you right now guys i've already tried this and it did not work so what i want to try to do here is i'm going to go ahead and i'm going to take the power probe i'm going to touch the main battery cable here as you guys can see we have full battery voltage now really what you want to try to do is if you can get somebody to turn the ignition switch to the crank position while you check the voltage here you want to make sure that you don't have a voltage drop across this cable unfortunately i'm kind of in a situation here where i'm on the side of the road and i don't have anyone here to help me and i'm actually kind of running out of time here so i need to make a decision quick so the next thing i want to do is i want to check the cable that goes to the starter solenoid and it's going to be this pin right here and what i want to try to do with this is i want to touch that connection with the power probe and i'm going to flick this rocker switch and use this power probe to provide a battery power to the solenoid and i want to see if this solenoid responds so i'm going to go ahead and try that real quick okay so i'm going to go ahead and flick the rocker switch and you guys can see nothing is happening so at this point i'm pretty sure that we need to replace the starter motor and like i said guys i'm here on the side of the road they're trying to get this thing up and running today and it's already four o'clock in the evening so i'm gonna go ahead and run down to the auto parts store pick up a starter motor and while we're at it we're also gonna replace the battery for this thing okay so this isn't a video about how to replace the starter i'm not going to go through the whole process but it's pretty straightforward there's two 13-millimeter bolts here the starter is going to come down and there's two cable attachments on the back that we need to remove sorry i'm not going to film that like i said that's not what this video is about and besides i really want to minimize my time underneath this vehicle because i am on the side of the road and i do worry about the cars that come flying down the street over here so like i said i'm going to go ahead and put the camera down and pull the starter out alright guys so we got our old battery and our old starter out you guys can see this starter looks like it's seen better days so let's go ahead and switch these out for new parts bam so we got our replacement parts here got our new battery acdelco and an acdelco starter so let's go ahead and get these installed okay guys so we got our replacement starter installed like i said it was pretty simple to do there's only two mounting bolts and then there's two bolts on the back side for the cables so i'm gonna go ahead and install the battery and see if we can start this thing all right guys so we've got our new battery installed now it's time for the moment of truth let's go ahead and move inside the vehicle and see if we can start this thing so i've got the key in my hand i'm gonna go ahead and stick it into the ignition and let's see if this thing cranks bam we are back in business all right so as you guys can see the engine is back up and running it just needed a replacement starter again we did our checks to verify that the starter was our problem now i am probably still going to recommend to the customer that we replaced that relay but i did also tell him that he should probably try to locate a lid for this fuse box because like i said you guys can see we got some water intrusion going on there we don't know if we have any other problems related to that but we do know that we definitely don't want to have any problems in the future so it's best to get that taken care of as soon as possible anyways guys i know this was a quick and easy video but i figure i'll bring you guys along hopefully you guys learned something if you liked the video please make sure to give it a thumbs up if you haven't done so already make sure you subscribe to the channel hit that notification bell and i'll see you guys in the next one [Music] thanks

Channel: ADVANCED LEVEL AUTO

Views: 39,320

Rating: 4.9102416 out of 5

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Id: z3wzyszZhPk

Length: 18min 39sec (1119 seconds)

Published: Fri Nov 06 2020