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Discussion Starter #21
One more thing. The car is on the 4th floor of a parking garage. Will I be able to push-start the car (given the possible malfunctions)? That would save me the hassle of having it towed.
 

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I did the post vs clamp test and that checked out just fine. Also measured voltage with the battery being jumped (13.6V) and without being jumped (12.4V). No difference in the reaction of the car.

I'll try to test the intermediate cables as well if I can locate them.


Start button: It lights up, but I don't know if this function is independent of the 'start' signal. How can I test that functionality? I unplugged and replugged it twice with no difference in result. I'll take a closer look at it again.


When I leave the key in the start position, all dash lights turn off except the Engine light, Oil light, Battery light, and Brake light. Is that normal?


MFRU and Starter are starting to creep in my head.
One more thing. The car is on the 4th floor of a parking garage. Will I be able to push-start the car (given the possible malfunctions)? That would save me the hassle of having it towed.
I think you've looked at starter button assy enough.

What is battery voltage right now?

If fuel pump isn't running (you don't hear it, right?), car can coast downhill but will not run.

Starter:
You can have someone press start button and look for volt reading at starter.

If you have no fuel pump, not likely the starter.
 

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Discussion Starter #23
I think you've looked at starter button assy enough.

What is battery voltage right now?

If fuel pump isn't running (you don't hear it, right?), car can coast downhill but will not run.

Starter:
You can have someone press start button and look for volt reading at starter.

If you have no fuel pump, not likely the starter.
The battery alone in the car is ~12.4. The battery while being jumped by my other car is ~13.6.

Correct, I do not hear the fuel pump running.

I also do not think it is the starter as I have never had an issue starting the car. I actually replaced the started in my accord a few months ago and went through the failing cycle with that car.
 

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If you turn the key and do not hear the pump for a few seconds then you won't have fuel for a push start to work. You'll just end up in a different parking spot.

Because the pump is supposed to prime at key on, this is pretty easy to troubleshoot with a voltmeter and the wiring diagram (available in the service manual that has been posted here). When you key on, the ECU should kick 12V to the MFRU which kicks 12V to the inertia switch which kicks 12V to the immobilizer which kicks it to the pump. Starting with the immobilizer is a good way to narrow it down to half the system. Disconnect the immobilizer and measure the voltage difference between the wire that comes from the MFRU and the chassis or battery ground. If this is 12V (I'm saying 12V but it should be exactly battery whatever that is), then you know your problem is downstream - immobilizer, fuel pump, wiring in between, or ground. Proceed with the same kind of probing and you'll find where the voltage train has been derailed. I left out where the fuse is because I can't remember exactly. Also, did you test the fuse by measuring the resistance across it while removed from the car? A common mistake is to prove it while still in the car which can give a false pass.

This is easiest with two people since you only have a couple seconds to read the voltage before it goes back to zero.


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It isn't the clearest, but start with checking pin 1 at the immobilizer (pretty easy with it disconnected but you may have to remove the washer bottle first)

ImageUploadedByAG Free1441753336.885038.jpg

And the fuse is between the ECU and MFRU, so check the voltage into the MFRU. If that's dead and the fuse is good, you may just have a loose positive which is bolted to a junction block on the firewall below the MFRU.


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Discussion Starter #26
If you turn the key and do not hear the pump for a few seconds then you won't have fuel for a push start to work. You'll just end up in a different parking spot.

Because the pump is supposed to prime at key on, this is pretty easy to troubleshoot with a voltmeter and the wiring diagram (available in the service manual that has been posted here). When you key on, the ECU should kick 12V to the MFRU which kicks 12V to the inertia switch which kicks 12V to the immobilizer which kicks it to the pump. Starting with the immobilizer is a good way to narrow it down to half the system. Disconnect the immobilizer and measure the voltage difference between the wire that comes from the MFRU and the chassis or battery ground. If this is 12V (I'm saying 12V but it should be exactly battery whatever that is), then you know your problem is downstream - immobilizer, fuel pump, wiring in between, or ground. Proceed with the same kind of probing and you'll find where the voltage train has been derailed. I left out where the fuse is because I can't remember exactly. Also, did you test the fuse by measuring the resistance across it while removed from the car? A common mistake is to prove it while still in the car which can give a false pass.

This is easiest with two people since you only have a couple seconds to read the voltage before it goes back to zero.


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I tested the fuses with the multimeter while they were still in the car. I'll try again with them out.

It isn't the clearest, but start with checking pin 1 at the immobilizer (pretty easy with it disconnected but you may have to remove the washer bottle first)

View attachment 597825

And the fuse is between the ECU and MFRU, so check the voltage into the MFRU. If that's dead and the fuse is good, you may just have a loose positive which is bolted to a junction block on the firewall below the MFRU.


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How would I access the MFRU? Do I have to put the car in the air?

Is the immobilizer the same thing as the inertia switch? (as far as checking Pin 1 goes)
 

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I tested the fuses with the multimeter while they were still in the car. I'll try again with them out.







How would I access the MFRU? Do I have to put the car in the air?



Is the immobilizer the same thing as the inertia switch? (as far as checking Pin 1 goes)

You shouldn't have to worry about the MFRU quite yet. It'd surprise me if you had two relays (starter and fuel pump) fail simultaneously though it isn't impossible.

The immobilizer is different and is the last device in the electrical chain before the pump although strictly speaking electricity travels from negative to positive but we won't go down that rabbit trail... It is located behind the driver's seat and is not the same as the inertia switch.

The good news is that the fuse is still possibly bad so pop it out and check before anything else. If it is good, that's also a good time to check the voltage going to it. I'm not sure which socket is which, so check both sockets. One of them should read battery voltage for a couple seconds after key on.


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Discussion Starter #28
You shouldn't have to worry about the MFRU quite yet. It'd surprise me if you had two relays (starter and fuel pump) fail simultaneously though it isn't impossible.

The immobilizer is different and is the last device in the electrical chain before the pump although strictly speaking electricity travels from negative to positive but we won't go down that rabbit trail... It is located behind the driver's seat and is not the same as the inertia switch.

The good news is that the fuse is still possibly bad so pop it out and check before anything else. If it is good, that's also a good time to check the voltage going to it. I'm not sure which socket is which, so check both sockets. One of them should read battery voltage for a couple seconds after key on.


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I checked the fuses out of the car and they're all fine. To check the voltage going in, do I just put the positive probe into the fuse hole and ground the other one to some metal piece?

Getting to the immobilizer seems like too big of a job for me. The alarm and dash tell tale all work though, isn't that what the immobilizer does?

I think I'm hearing a solenoid click once a split second after I turn the key on, and another right after I turn it off. I need to get someone to twist the key when my head is in the bay so I can pinpoint the location of the click. It's not very loud, but it's there.
 

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I checked the fuses out of the car and they're all fine. To check the voltage going in, do I just put the positive probe into the fuse hole and ground the other one to some metal piece?



Getting to the immobilizer seems like too big of a job for me. The alarm and dash tell tale all work though, isn't that what the immobilizer does?

Right with respect to probing the fuse.

No need to touch the immobilizer yet either. Try the fuse sockets first then go from there. If you see the voltage for a couple seconds on fuse R1, then disconnect the inertia switch and probe #1 for the same test (assuming that the inertia switch hasn't been tripped, so check to see if it clicks when you press the rubber button). After that, you'll need to remove the driver's seat or passenger seat then the rear plastic trim. A ball-end allen socket will make really short work of that, but again, don't worry about jumping ahead until you need to. You can also try connecting battery voltage directly to pin #3 which should run the pump if the immobilizer is readied.

Lastly, it is possible for the immobilizer to be okay except for certain circuits. For example, my immobilizer's fuel pump circuit is fried. The red light acts like normal and the starter runs but the pump wouldn't run so now I've just jumped that part of the circuit.






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Discussion Starter #30
Right with respect to probing the fuse.

No need to touch the immobilizer yet either. Try the fuse sockets first then go from there. If you see the voltage for a couple seconds on fuse R1, then disconnect the inertia switch and probe #1 for the same test (assuming that the inertia switch hasn't been tripped, so check to see if it clicks when you press the rubber button). After that, you'll need to remove the driver's seat or passenger seat then the rear plastic trim. A ball-end allen socket will make really short work of that, but again, don't worry about jumping ahead until you need to. You can also try connecting battery voltage directly to pin #3 which should run the pump if the immobilizer is readied.

Lastly, it is possible for the immobilizer to be okay except for certain circuits. For example, my immobilizer's fuel pump circuit is fried. The red light acts like normal and the starter runs but the pump wouldn't run so now I've just jumped that part of the circuit.






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Ok. What am I looking for while testing R1 before and after disconnecting the inertia switch? 12V before and 0V after?

FYI, The clicking that I mentioned in the earlier post seems to be coming from the ECU.
 

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Ok. What am I looking for while testing R1 before and after disconnecting the inertia switch? 12V before and 0V after?



FYI, The clicking that I mentioned in the earlier post seems to be coming from the ECU.

I must've missed that when skipping over San's lecture. It is the MFRU that is clicking but that doesn't mean you can put the fuse back yet. I reread the diagram and the voltage at the fuse is constant and not the temporary 12V. Either way, you should still probe it. The inertia switch isn't relative.

If you see 12V at the fuse, then the MFRU is next to check but it's hard to get to so the pin 1 at the inertia switch is the output from the MFRU and is the easiest way to check the MFRU.



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Discussion Starter #32
The noise comment was an edit I made a few posts ago. You probably clicked reply before I made the edit.

Tested R1 port, 12.28v, same as battery. Getting to the point where I need a charge again.

So next I am testing the mfru by testing the power going from the mfru to the inertia switch. I do this by probing the connector at the bottom of the inertia switch. Correct?
 

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The noise comment was an edit I made a few posts ago. You probably clicked reply before I made the edit.

Tested R1 port, 12.28v, same as battery. Getting to the point where I need a charge again.

So next I am testing the mfru by testing the power going from the mfru to the inertia switch. I do this by probing the connector at the bottom of the inertia switch. Correct?

Correct; disconnect that switch and probe pin 1. If that shows 12V, then use a spare wire, paperclip, etc, to jump pin 1 and 3 together. That will work if the inertia switch was dead.


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Discussion Starter #34
Correct; disconnect that switch and probe pin 1. If that shows 12V, then use a spare wire, paperclip, etc, to jump pin 1 and 3 together. That will work if the inertia switch was dead.


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Alright. I'll do that first thing in the morning.

What are you suspecting the culprit is right now?


Thanks for all your help by the way!
 

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Alright. I'll do that first thing in the morning.



What are you suspecting the culprit is right now?





Thanks for all your help by the way!

My guess is either the starter button or the immobilizer, but I've not had to hunt down starter button problems before so I've not looked closely at it. The service manual will tell you the wiring schematic though.

To clarify, the starter motor does not spin, right?


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Actually, I'm pretty sure it is the immobilizer. A bad starter switch will still prime, just not crank. Either way, it's best to proceed systematically and just check one thing at a time until you find the bad link


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Discussion Starter #37
My guess is either the starter button or the immobilizer, but I've not had to hunt down starter button problems before so I've not looked closely at it. The service manual will tell you the wiring schematic though.

To clarify, the starter motor does not spin, right?


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Correct, there is no priming or cranking.

Actually, I'm pretty sure it is the immobilizer. A bad starter switch will still prime, just not crank. Either way, it's best to proceed systematically and just check one thing at a time until you find the bad link


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Ok. Off to check PIN 1 at the inertia switch. Had a couple PMs telling me to re-sync the fob. That was the very first thing I did in this whole cycle, but I'll give that another shot too.
 

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This exact thing happen to me, turned out I had to re sync the fob. When I tried to re sync it did not work. I never use my second fob, but remembered I had one. Started the car with second fob, then was able to re sync the primary one. You may need to ask Sir Lotus how to get it to re sync if you don't have a second one.
 

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Discussion Starter #39 (Edited)
Re synced a few times. No change.

Probed all 3 pins (didn't know which end was 1 vs 3) from the connection going into the inertia switch. All 0V.

The thing is, the pin holes are pretty small relative to the probe on the multimeter, so I'm only 95% I was making contact with the metal inside the pin.


If I was making proper contact, this points to the mfru, correct? That would explain why the fuel pump is not priming and why the starter isn't cranking. Rather than both of those internal relays being bad, maybe the whole mfru isn't getting power?

Another thought: Looks like I can test the power going to the mfru by seeing if fuses R6 and R7 are getting power. Before, I had only checked R1.


this whole process is staring to make sense to me...
 

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Discussion Starter #40
Verified via multimeter:
R8 is the only fuse not getting any power.
The Inertia switch is also not getting power.
 
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