Multiplex control unit/immobilizer problem SOLVED
#1
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my fellow civicheads I have a problem...
I replaced the MCU in my 2002 civic. Now the car is a no crank/no start.
It clicks, but the starter will not turn at all. Prior to installing the MCU I had the common symptoms....no door chime, no low wiper setting, power doors/keyfob not functioning, a/c inoperable....all of those issues are resolved, but the car will not turn over.
The part number that I bought was a 38200 5sp a31 p3...it replaced a 38200 5sp a31 c1.
I'm thinking that it could be a programming issue with the immobilizer...
Any suggestions?
I replaced the MCU in my 2002 civic. Now the car is a no crank/no start.
It clicks, but the starter will not turn at all. Prior to installing the MCU I had the common symptoms....no door chime, no low wiper setting, power doors/keyfob not functioning, a/c inoperable....all of those issues are resolved, but the car will not turn over.
The part number that I bought was a 38200 5sp a31 p3...it replaced a 38200 5sp a31 c1.
I'm thinking that it could be a programming issue with the immobilizer...
Any suggestions?
#2
If you think a good mechanic is expensive, try hiring a bad one
re: Multiplex control unit/immobilizer problem SOLVED
Does the green key light flash angrily when you try to start the car?
Immobi system type 3 info:
http://www.tegger.com/hondafaq/tsb/civic/x01-053e.pdf
I don't see that the MICU is part of the immobilizer system in the type 3 version.
Probably likely you didn't get one or more of the harness connectors fully seated in the fusebox, or didn't get all the little items transferred over to the new box?
Plug your old fusebox back in and see if it runs again?
Those numbers as typed aren't working in my parts catalog.
Immobi system type 3 info:
http://www.tegger.com/hondafaq/tsb/civic/x01-053e.pdf
I don't see that the MICU is part of the immobilizer system in the type 3 version.
Probably likely you didn't get one or more of the harness connectors fully seated in the fusebox, or didn't get all the little items transferred over to the new box?
Plug your old fusebox back in and see if it runs again?
38200 5sp a31 p3...it replaced a 38200 5sp a31 c1
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the correct number is 38200-s5p-a31.
I felt like it could possibly be a loose connection, hopefully I didn't pull any wires out of the harnesses...some were a beast to pull.
To my relief the green key stopped flashing...it was flashing before I changed the unit also. I was waiting for the car to stop working at any point, now it decides to stop AFTER i install the MCU! go figure.
Ill take another look at my work and update you.
I appreciate your help.
I felt like it could possibly be a loose connection, hopefully I didn't pull any wires out of the harnesses...some were a beast to pull.
To my relief the green key stopped flashing...it was flashing before I changed the unit also. I was waiting for the car to stop working at any point, now it decides to stop AFTER i install the MCU! go figure.
Ill take another look at my work and update you.
I appreciate your help.
#5
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Sooo...get this. I went out to start checking the fuse box connections. Before I started of course I stuck in the key to see if it turned over miraculously...it did.
So, after two days of sitting non responsive...this morning the blinking green key stops flashing, but the car was still a no crank no start...now it starts, all issues are resolved. BUT...the blinking green key is flashing again.
It was flashing the whole time and I know this is the immobilizer. Question is, will it eventually shut down the car or auto-correct itself?
Am I completely out of the dark here or what?
So, after two days of sitting non responsive...this morning the blinking green key stops flashing, but the car was still a no crank no start...now it starts, all issues are resolved. BUT...the blinking green key is flashing again.
It was flashing the whole time and I know this is the immobilizer. Question is, will it eventually shut down the car or auto-correct itself?
Am I completely out of the dark here or what?
#7
If you think a good mechanic is expensive, try hiring a bad one
re: Multiplex control unit/immobilizer problem SOLVED
So now I can't answer if it needs to have something done with programming or not....but I'll *guess* the issue won't be in the MICU.
I'd plug in my HDS scanner to find out more info if possible (status logs and health checks), and there's a whole section in the service manual for troubleshooting hard faults with the immobi system.
MORE EDIT: Come to think of it, I've had a couple with issues caused by 'dirty' connections (microcorrosion, terminal fretting).
Low battery voltage can cause the immobi system to be unable to read a key, thus not let the engine start.. So can a problem with any part of the immobi system and its wiring.
Does the car have remote start or anything aftermarket like that?
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Nothing aftermarket except the radio.
Yesterday after it started, I turned it off and on 5 times then drove it for 30 mins. Came home and turned it on and off a few more times.
This morning it is a no crank/no start again.
The green key flashes 3 times when it returns to the on position.
Yesterday after it started, I turned it off and on 5 times then drove it for 30 mins. Came home and turned it on and off a few more times.
This morning it is a no crank/no start again.
The green key flashes 3 times when it returns to the on position.
#9
If you think a good mechanic is expensive, try hiring a bad one
re: Multiplex control unit/immobilizer problem SOLVED
The green key flashes 3 times when it returns to the on position.
Copied from an 02 owners manual:
When you turn the ignition switch to
ON (II), the Immobilizer System
indicator should come on for a few
seconds, then go out.
If the indicator
starts to blink, it means the system
does not recognize the coding of the
key. Turn the ignition switch to
LOCK (0), remove the key, reinsert
it, and turn the switch to ON (II)
again.
The system may not recognize your
key’s coding if another immobilizer
key or other metal object is near the
ignition switch when you insert the
key. To make sure the system
recognizes the key code:
Do not keep other immobilizer
keys on the same key ring.
Use a plastic or leather key fob,
not metal.
Keep other keys away from your
car’s key and the ignition switch
while trying to start the engine.
If the system repeatedly does not
recognize the coding of your key,
contact your Honda dealer.
So AFTER that light flashes 3 times: while you continue cranking but the engine won't start, what is the green light doing?
If you were to bust out a voltmeter and check voltages at various places.......Time to get some service literature or visit a dealer?
Will it run on the old fusebox?
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Cool -- can the title be edited to SOLVED? Mods?
One of those electrical gremlins that you can't really forsee without getting your hands dirty, excellent.
One of those electrical gremlins that you can't really forsee without getting your hands dirty, excellent.
#12
If you think a good mechanic is expensive, try hiring a bad one
Re: Multiplex control unit/immobilizer problem SOLVED
#13
Re: Multiplex control unit/immobilizer problem SOLVED
After reading this im wondering what wires caused your issue? I find it strange that all 3 components started to act up at once. I had diven to car home, 30 minutes later this happened. All at once.
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