223: Honda Civic Crank No Start

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Hey, what's going on?

Automotive World.

Welcome to another episode of the Automotive Diagnostic Podcast.

My name is Sean Tipping and I'll be your host once again for today's episode.

Thank you for joining me.

Got a quick case study for you here today, this one.

I guess the end result not that surprising.

I kind of had an idea going into it, what I might find, and you might too, by listening to it, but the reason that I wanted to share it again.

I've mentioned this several times in the last few months.

I'm trying to get vehicles on the podcast that have beat me up a little bit, that we've struggled with, to get to a solution, and, of course, I'd like to share the ones that we do get to a solution to, but also the ones that maybe challenge us a little bit along the way and why it challenged us, because you might run into the same thing and this could be helpful.

But it's also, I think, valuable just to share, for everybody, to share what their struggles are.

Right, because there might be somebody out there listening who knows this extremely well and they're like, oh well, you just needed to look at this or you just needed to think about that as you were going into this problem and you wouldn't have struggled here.

Or, yes, this is the way all of these things are, it's just the way it is.

Okay, well, now you know, right, but to put our struggles out there so that we can share in the knowledge that we have, and also just an observation that, hey, these cars are not easier and they're not getting any easier, but this one, I feel like, should have been pretty easy.

This is a 2009 Honda Civic and this was a crank no start.

Actually, I'll back up here a little bit.

It came into the repair shop that I did the mobile call for as a no crank at all.

Okay, so the engine didn't crank at all.

Now the customer is going back even further.

The customer Attempted to fix their no crank.

That's what this originally was.

The engine did not turn over by putting a new battery in it and that did not fix it.

But the shop Although I don't think they got a clear-cut answer was suspicious that that the customer had either connected the battery cables backwards or jumped the vehicle Backwards at one point or another, and they said this from the discussion that they had with the customer.

The customer didn't outright say that, but when you've done this long enough, you can kind of pick up on things like that.

When you have a discussion with the customer about you know what was done, what was tried, how did you do it, blah, blah, blah, and they're like, yeah, I think they may have jumped this backwards.

Okay, so they ended up getting you know new battery unit, everything connected, and they ran up against the no crank as well and they followed their normal diagnostic procedure.

Same thing I would do.

Right.

Go to the starter relay.

Okay, it's working.

Go to the starter.

Hey, we're getting power on the big cable and the s-terminal.

This thing should be cranking.

Right, the block has a ground.

Okay, let's put a starter in it, which they did.

And then it cranked, but it did not start and they tried scanning for codes.

They were not able to communicate with the PCM, and that was the time that they called me.

This is a shop that's really competent, but they're also really busy and when they get things like this, they want to keep their technicians going on the parts hanging in the gravy work, the stuff.

That's real money makers and hey, I get it totally.

That's why I'm there to fill in those spots, to make their lives easier.

That's the service I offer.

So that's why they called me.

They just want to figure out.

Okay, hey, you know we think this thing might have been Jump backwards.

We can't talk to PCM.

It's very possible it is a PCM that's failed.

Can you just come in and verify for us that?

That's what this is.

So you know they're kind of setting me up to dial into what's wrong, but Me doing my job, I got to be careful.

That right.

I don't want, as you wouldn't want, the customer, the driver, the car diagnosing the problem for you off of a video they watched on YouTube, right?

I don't want my customer leading me to something without me even doing any checks, so I try to ignore that stuff, like right.

I want the information as much as possible and I try to question my customers as much as I can, but I do have to kind of look at these things fresh and say I'm not going to just jump out of the component they think it is.

I'm going to approach this like I normally would, with my process, because I know my process is going to get me to the Solution.

But I'll keep it in the back of my mind that that's what they said May be helpful as I proceed.

So I get to the vehicle and this thing does crank turns over.

Now, first things that I notice, and this is important and part of what threw me off.

Number one the check engine light is on the dash.

Okay, now I can't say I mean I work on a lot of Hondas but I can't say I'm familiar enough with every Honda make and model to say if the PCM Power train control module is offline or if the ECM is offline, is that going to disable the check engine light.

In a lot of vehicles it is, and if you were to ask me, is that that way on a Honda?

I'm like, probably, but this is just initial looking at it, I haven't even hooked up my scan tool yet.

The check engine light is on and it cranks.

I do not have an immobilizer light and I do a lot of key work on these Hondas too, and there's a green Key shaped light, which is the immobilizer light that is normally on the dash, and this is when you go turn the key on.

You should see this at least turn on and turn off.

I think it is even on once you pull the key out.

I could be wrong on that, but you should see this little green immobilizer light.

That light is not on at all.

All right, cool, so that's what I've got cranks, check engine lights on, green immobilizer light is not on.

All the other electronics in the vehicle appear to work, but I'm going to hook up my scan tool.

I'm going to scan it and see what I got.

Now.

I could talk to a number of modules on the car, but two that I cannot talk to are the immobilizer and the PCM.

Okay, now, again, strangely, the check engine lights on but I can't talk to the PCM or whatever let's you know, go with our diagnosis and see what we can get.

But because I can't talk to the immobilizer and I can't talk to the PCM, I have to make a decision of which module I'm going to start with, and a lot of times I might go with what's easier to access.

But before I even do that, right, and the PCM is under the hood by the battery.

The mobilizer is on the column.

You got to pull apart the shell on the column to get to the immobilizer unit.

It's right where you would stick the key.

Before I do that Because I'm trying to be smart here, trying to be efficient, right, I want to look at the diagram and see do these things share anything?

Right, two modules I can't talk to don't seem to be working.

Do they share any common Electrical like fuse or ground or something like that?

And I look at the diagram and I I don't see any power feeds that they share.

But what I do see is a ground on the back of the cylinder head that they do share and I'm like, oh okay, well, this might be easy because they, they both share this ground and they both don't work and it's right on the back of the cylinder head.

I visually inspected it looked okay, all right.

Well, maybe I'll have to go to the module and actually check to see if there's a good ground there.

But visually it looks like it's tight and on the back of the head and there's there was actually some Identification hits on this particular ground, causing some issues.

But visually seems to be okay, all right.

Well, let's, let's go to a module and start testing.

And I decided to go after the mobilizer module first.

I realize they can't talk to both of them, but the PCM has Three bolts and you have to actually, well, you're supposed to remove the battery, you can get it out, but it's kind of a pain to get to the connectors.

The connectors are buried, not that I'm, you know, not going to.

But again, I'm gonna go with what I think is easiest first, and in this case I'm gonna go with a mobilizer.

This is just three screws on the bottom of the column.

Pull apart the shell and I got my mobilizer right there, okay, so pull it apart.

I check I've got power to this thing, I've got ground to this thing, and I believe there was power on two wires and ground on the other.

And this is the ground from the cylinder head that I was suspicious of, because it feeds both the mobilizer and the PCM.

That was good.

Let's have a headlight bulb, okay, so it's got power on ground.

I'm like huh wonder, number one why doesn't communicate with number two, as the light not on, if it's got power and ground, you think, even if it didn't Communicate that the light should be on.

But then again I don't know the circuitry for the light right off the top my head.

Of course I got a diagram in front of me and I can look at it.

But is the LED for the indicator lamp directly tied to the mobilizer?

Is it over a data line?

I don't know.

But here's my other question Is this module turning on?

Right, it's got power and ground, so it should be.

Here's what I did to see is the module doing anything?

The module, the immobilizer modules, also the halo that goes around the lock cylinder for the ignition.

So it's got a coil wire and when you turn the key to the on position, that triggers that coil to send out electromagnetic waves which is actually going to Excite the transponder in the key and that key is going to send data back to the immobilizer module right If you have a key tool max and there's other tools that do this.

But I love the key tool max.

It's a great little thing for programming keys, but also for diagnostics, because you can read keys and see it as a chip read and then you can also Read to see is this halo, is this immobilizer module Whatever it is Sometimes it's just an antenna ring Is it outputting a signal to doing something?

When you cycle the key?

And what's cool about the key tool max and actually the autel cam 100 to do this too It'll tell you what transponder chip responds.

Well, if a key responds.

And then if it does, what is the transponder chip type in that key, which is pretty cool, right it?

Especially if you're like is this right key for this vehicle?

And you might say well, how would it be the wrong key for the vehicle if it turned the ignition?

That sort of stuff happens all the time, so it is useful to know is it the correct type of chip for the vehicle?

But really all I'm looking for here is yeah, I'm not necessarily worried about the key in this case.

I just want to know is the model turning on is doing something?

So I cycle the key and I'm able to read Activity from the coil and it even shows me the chip type.

I think it was a 46, but okay, cool.

So it is turning on again.

Can't talk to it and what was there?

Lights not on the dash, what's going on?

So let's look at communication here.

Now.

The confusing part about this is there are three different data lines going into this immobilizer module.

There's a beacon, a K line and what they call an s net.

This is all communications between various modules on the vehicle.

Now the beacon, which I think is body can, and the K line, which actually goes to the Now pin 7 of the DLC, communicates with the scan tool.

And then some other modules as well.

Those have activity on them.

And when I say activity, like they're not Grounded out, they're not shorted to voltage, they're not corrupted, I just see activity on those wires.

Okay, the s net, I don't, and in the moment I don't know what s net necessarily means.

I see that it's going to the under hood fuse box, I See that it's going to the under dash fuse box and to the ECM and that's it.

That's the entire s net network on this O9 Civic, but I'm not entirely sure what it is, but I'm thinking okay, well, this is probably mobilizer, data of some sort being transferred to the ECM, but there's no Activity on this wire.

I should say there's, there's a bias voltage, but there's no data transmission on this wire, there's nothing happening, it's just blank.

And I cycle the key and nothing really happens on here.

Okay, so I'm kind of at a dead end with this module here.

I don't know what this s net is, I don't know if it's required for this thing to power up.

It seems to be taking key data, it seems to be turning on, but I don't really have a great answer here as to what's going on.

And again, I still can't communicate with my PCM.

Now, the network that the scan tool uses to communicate to the mobilizer and to the PCM, I think the PCM it's going to communicate over the CAN boss and the mobilizer over the K line, those data line.

Those networks are Functional because I can talk to a bunch of other modules on those same networks.

Okay, so where do I go now?

I'm gonna switch gears and go to my PCM.

I don't have a for sure answer on this and mobilizer.

I'm kind of kind of up against the dead end here.

I thought I was gonna find something, but let's transition to the PCM and maybe I'll find something there.

And I've said this a lot when it comes to electrical, if you have multiple electrical problems that, at least you Assume, have all occurred at the same time, pick one Thing and go for it, and a lot of the times it will you'll, it will lead you to the solution that fixes everything.

And I can't tell you how Many times I've used that.

And it's been super helpful to kind of cut out the noise of things Right, especially if there's, you know, something like a body control module and there's just a ton of stuff that doesn't work or doesn't work right, and you're almost overwhelmed by the different paths that you could go and try and, before you've gotten the solution, trying to comprehend exactly, well, what single electrical fault could cause all of these problems.

Just pick one thing, one Circuit, and figure out why that one circuit's not working, and if you can get to that solution, you're probably gonna find the rest.

It's worked for me a lot just to cut out the noise and focus me in on one problem and it gets me the solution for all of them.

But anyways, now I'm gonna switch gears and go for the PCM.

I'm just gonna see why it can't.

I talk to the PCM and Maybe that will get me back and answer my question about the immobilizer.

So it take the time get the PCM in a position where I can get the connectors on it.

And this is another point.

We're got a little confusing for me now.

Again, I work on plenty of Hondas and I Diagnosed some PCMs on Hondas before and it may have been this case and I just didn't recall.

But I'm looking at the power and ground distribution for the PCM and I found a couple powers and a number of grounds.

I think there's four or five grounds.

But the power feeds into the PCM.

From what I could find on every diagram, including the factory one but the redrons as well, there's no Constant power feed to this PCM.

All that I have on this PCM for power feeds again that I could find and I'm using the factory diagram, check this for yourself.

Oh, nine civic, I think it was an EX there's a switched power feed that comes into it through the from the ignition switch through a fuse.

There's a switch power feed and then the other.

The only other power feed to this PCM is through the PGM Fi main relay one, but that relay is Actually grounded by the PCM.

Okay, so what I'm getting at here is this doesn't have a constant power feed, and this threw me off.

And Again, if you're a Honda tech, you're probably like, well, yeah, that's just how they are, that's all they've always been.

But I was scratching my head.

I'm like, shouldn't this thing have a constant power feed?

And I'm still a little confused by it because, from everything I found, it does not.

I'm like, well, how does it retain Learned a memory?

I mean, I've realized there's non-volatile memory and that must be what it's using.

Right, because If, for no other reason, there's learned things like field trims and shift points for the transmission and OBD2 monitors, right, how well, how does it save the OBD2?

Monitor data?

I don't think it's done in another module.

It's, from what I understand, that's got to be within the PCM.

But if you turn off the ignition to this, based on what I see in the diagram, all, all powers cut off to this module.

There's no memory circuit, there's no constant power, and so that threw me off for a while and I really searched through all the diagrams that I could find for this vehicle.

So I'm like it's got to have one.

There's gotta be a constant power feed, right.

It just doesn't make sense for it to not have one.

But it doesn't.

Okay.

Now I do have power on the one that comes from the ignition switch.

I don't have power on the PGM fi relay output.

But if my PCM is dead or not functioning for some reason, I could understand why that might be.

Now the question I also didn't know was like well, if that PGM relay is not working or it's out or whatever, and not saying power, will the module not turn on and not talk?

Right?

Is it one of those situations where maybe it self excites itself and before it does that is not gonna talk?

Most ECM PCMs that have that you know PCM power relay that self excites itself, right, it grounds the relay that provides power back to it.

Most will still communicate even if that doesn't work.

But there are examples where that's not true.

Toyota is one of them.

I mentioned that before.

That's got to be there if you want that PCM to communicate, okay.

So the easy thing to do here for me right now, just to see, is this my problem Is I'm gonna jump power to that circuit, I'm gonna be the PGM relay and I'm gonna send power on there and just see.

Does anything change?

Does my PCM wake up to start talking?

Can I start this thing?

I do it, nothing happens, all right.

And I check to the ground side, the control side, for that relay.

It's not grounded, regardless of what I do, so it's not even trying to turn this relay on.

Okay, so from what I can tell, I got all my powers and grounds necessary for this PCM to turn on and to talk.

Now I'm also thinking in my head Okay, they said something about being John backwards.

All right, that's totally possible.

But what else could be causing this scenario?

And I'm also thinking why isn't the mobilizer module Working, as far as what I can see?

The one other thing I wanted to check here, because there wasn't really coming up with anything else, was the 5 volt reference circuit off of the PCM.

And If there's you know somewhere on that 5 volt reference circuit where it shorted out, it could potentially be causing the PCM to not turn on, to not function, to not communicate.

So I want to check that.

Right, I'm getting closer, at least calling a PCM here, but I need to check that 5 volt reference.

So this was interesting and I have run into this before.

The way I check a 5 volt reference to see if it's shorted to ground is I will take my test light and I will power up my test light, right, so the clip end of your test light, I'm going to put it on b plus and then I'm going to touch that 5 volt reference.

If it's shorted to ground, it's going to brightly Light my test light and then I just need to find the short to ground right now.

Now, sometimes with a PCM that is dead, just completely out to launch, and not because of the 5 volt reference, but for another reason you can sometimes see your test light light up on a 5 volt reference that's connected to a PCM that is not functional at all.

So be careful, use this method and I've let that kind of distract me before With dead PCMs causing that light to light up.

In that case Now, how could you verify?

That's what it is?

You could unplug the PCM and then, if your test light goes out, you know that the five volt circuit is not shorted.

But there's there's always a butt, there's always variables.

Be careful of that too, because the five volt reference Canon does go in and out of the PCM on multiple circuits, right, multiple wires, depending on where you're measuring it.

And Let me give you it's a real-life situation that I screwed up.

It was a Toyota Corolla that I was doing this on and I'm like, oh okay, the five volt reference, when powered up, lights up my test light.

Is it out on the circuit or is it the PCM?

Let me just unplug the PCM.

Oh, my light goes out.

Okay, well, it must be the PCM that's at fault.

No, it was another leg of that five volt reference circuit that went to a fuel tank pressure sensor and when I unplugged the PCM I separated that from that five volt reference under the hood that I was measuring with my test light.

Okay.

So again, a lot of variables there, but just be aware.

Number one a dead PCM cause your light to light up on your test light if you're doing the test that I'm doing.

But then also, that five volt reference goes into the PCM in multiple places.

Okay.

So I took a different approach to this one when I was because it, because my, my test light did light up on the five volt reference.

Here I wouldn't say it was brightly, but it lit up and I want to determine Is it an actual short to ground on the five volt, or is it in the PCM or is it just?

I shouldn't even say is it in the PCM, but with a PCM that just doesn't turn on at all, doesn't do anything.

It can light up the test light on that five volt reference and I don't know if you'd call it normal, but it is what it is when that thing's not functioning, and I've seen that on a Ford before the same thing.

So here's what I did on this particular one.

This isn't gonna work on every vehicle, but it worked on this thing.

There's a comb on the back of the cylinder head that has connections for all of the different five volt legs for this vehicle or for the engine, I should say, off of the PCM.

And again, there's multiple feeds, multiple five volt references, but they all come to this comb.

Are all the ones that I'm concerned about.

As far as being shorted to ground, right, you don't have to worry about a thermistor being shorted to ground, that's how they're designed to work.

But things like the map sensor and the output speed sensor and this and that, right, and what I can do here is I can pull these Combs and I separate all of those legs from the PCM Right, and then I think I had three wires going into this comb that were five volt references from the PCM and I check those, and all those going straight to the PCM lit up my test light and none of the other ones did so.

What that means to me is there's not a leg of the circuit, there's not a sensor, there's not something else that's grounding out this five volt reference.

I think this PCM is just dead to the world and that's what I'm dealing with here.

Okay, and so now I'm left with hey, I'm pretty sure this PCM is out to lunch, not doing anything, not turning on, not communicating.

Why is the check engine light on, though?

I was thinking that.

Well, I did a little bit of digging here and come to find out the check engine light itself Isn't directly controlled by the PCM in this case.

A lot of times it is, I'd say most cases it is, but not in this case.

This Check engine light, or the malfunction indicator lamp, is controlled by the instrument cluster in this, and it must be getting data over the communications network and in the case where the PCM is not online, it's just going to turn the check engine light on.

This is something I learned when I was working on this vehicle.

Now the mobilizer light is also controlled directly by the cluster.

Now why that's not on, I'm not sure at this point.

But here's what I know.

This PCM is definitely out.

I'm not sure on the mobilizer.

I can't communicate with it with my scan tool.

But I was wondering two things here.

Number one is the communication thing, a scan tool thing, and so I grabbed a second scan tool.

It was the same thing, like probably not two different scan tools, but who knows.

But also, is this something where the PCM needs to be online?

Right, I've got that s net, which I ended up finding out is security network.

That's the Honda lingo, from what I could find and that is between the ECM and the mobilizer.

And I mentioned there was no, no activity on there.

Does the ECM have to be online?

Is it the master of that data network?

Potentially it's possible.

I don't know that.

I couldn't find anything that really outlined that, but I'm kind of thinking that might be the case.

So I told the shop.

I was like, hey, there's a couple weird things here, but I know for sure this PCM is out.

Will you order one?

We'll get a program for you and then we'll verify everything else.

And in some cases that's the best step is just to say, hey, right, there's, there's a couple question marks, but I know for sure this part's bad, let's get this part and then move forward, and then we'll see where we're at.

So a couple days later they have us come back.

Actually, my employee ran out there and I told them the scenario and like, hey, let me know what you find.

Um, they pop a brand new PCM into this thing, which, if you get new Honda PCMs at least for this era, but I can say all the way up to like 17 they don't have to be programmed like you don't have to put a flash in there, all you have to do is write the v in and match the mobilizer.

And you can do that with aftermarket scan tools, and we did so.

I mean, I guess, to check for updates.

But it's a brand new module and I haven't found that that's the case.

Uh, hondas just don't need updates very often, unless it's a odyssey with a torque converter clutch, but anyways, it's easy enough to do with.

I aftermarket scan tool matched the mobilizer right, the v in, and we were able to do that.

And I asked my employee I'm like the mobilizer light on, oh, it turned on better than it turned off.

Once it started, and it did start, I'm like, oh, okay, so then we're all good and I think my assumption was right that the ECM needs to be on line to get the mobilizer To communicate.

Now, why didn't talk to my scan tool?

I'm still suspicious that maybe I had a scan tool issue with it.

But again, maybe it's something where the ECM has to be online and functional In order for that a mobilizer to kick in and do anything.

If you're a Honda guy and that doesn't make any sense, please let me know.

Be curious to know what I was missing or how I perceived that incorrectly.

If I did, if that is the way that it works, I will also be curious to know what's your experience with those.

But again, it was just a PCM that was out and it makes sense.

They probably did jump it backwards, would be my guess, because there was a starter that was failed.

They said it was a no crank and I think that's what the customer was initially trying to repair.

But then they built in another problem.

But check in to light on when the PCM is a no-com, no-function, and immobilize the light, not on, when we didn't have to replace anything with the immobilizer system Once we got the PCM in there, everything functioned correctly.

So curious and that's the reason I wanted to bring it up is those little things.

Like you, we diagnose a lot of modules, right, we go through a lot of different things and I, you know, we have a routine when we have stuff that's wrong.

Okay, right, we have a module that's on, let's check powers, let's check grounds, let's check communication.

Oh, and you know I probably forgot to mention I did check the cam lines to the PCM and those were, those were functional as well.

I think I skipped over that when I was going through my checks here.

But you know, you check all that stuff and okay, well, what happens when, like I said, there wasn't a constant power to this thing?

That kind of threw me off, the light thing kind of threw me off, the immobilizer threw me off, and it took me way longer to shut off, right, but that's the sort of stuff that happens out there.

So again why I wanted to share it.

I thought that was interesting enough to bring up on the podcast, but let me know if you got any thoughts on it.

That's all I got for you.

Thank you for listening, really appreciate it and appreciate all the feedback.

So keep it common.

But with that out of the way, let's get out there and start fixing the world, one card a time.

Honda Civic

Toyota Corolla

Honda Odyssey

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