Possible MCU and ECU problem
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Hello All!
First let me say happy Memorial Day to everyone and a big thank you to all who have served and are serving to protect this great country of ours!
I have a 2001 civic lx that I bought w/out much research b/c I needed something quick and have had great luck with civics. The little problems I had with the car pointed to a bad MCU: A/C does not work, dome light not coming on when doors opened but works with switch, power locks not working. The guy I bought it from bought a new key fob on line and I could not get it programmed using the steps he gave. I ordered a MCU (cabin fuse panel) off of eBay but it did not have the support for power windows. I connected it and the A/C fan came on but car would not start, so I put the old fuse panel back in the car. After re-installing the old fuse panel the car still will not start. The key light blinks rapidly and I can hear a rapid clicking behind the glove compartment and the car engine will not turn over. Do you folks think it's possible that the MCU and now the ECU are both bad?
Thanks!
First let me say happy Memorial Day to everyone and a big thank you to all who have served and are serving to protect this great country of ours!
I have a 2001 civic lx that I bought w/out much research b/c I needed something quick and have had great luck with civics. The little problems I had with the car pointed to a bad MCU: A/C does not work, dome light not coming on when doors opened but works with switch, power locks not working. The guy I bought it from bought a new key fob on line and I could not get it programmed using the steps he gave. I ordered a MCU (cabin fuse panel) off of eBay but it did not have the support for power windows. I connected it and the A/C fan came on but car would not start, so I put the old fuse panel back in the car. After re-installing the old fuse panel the car still will not start. The key light blinks rapidly and I can hear a rapid clicking behind the glove compartment and the car engine will not turn over. Do you folks think it's possible that the MCU and now the ECU are both bad?
Thanks!
#2
If you think a good mechanic is expensive, try hiring a bad one
Re: Possible MCU and ECU problem
See if the alternator mounting bolts are loose.
See if the 2 sets of ground wires on top of the upper water neck are loose.
MICU failures are somewhat common.
PCM (ecu) failures are not common, they are usually caused by loose alternator bolts or bad grounding of the powertrain.
Will a scanner or code reader communicate with the PCM?
See if the 2 sets of ground wires on top of the upper water neck are loose.
MICU failures are somewhat common.
PCM (ecu) failures are not common, they are usually caused by loose alternator bolts or bad grounding of the powertrain.
Will a scanner or code reader communicate with the PCM?
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Hey, thanks for responding. The alternator seems to be mounted securely, I checked the bolts and they are tight. I also see the ground wire and it is tight and seems free of corrosion. I hooked up my code scanner and when I turn the key to On (II) the screen on the scanner flashes rapidly, icons on the dash do the same and I hear the rapid clicking noise from behind the dash.
The car was running fine until I swapped out the fuse panels, just did not have a/c and the other little problems I described. It does appear whoever owned it before me was mucking around with the wiring since there is electrical tape around some of the wires, but was running until MCUs were swapped.
The car was running fine until I swapped out the fuse panels, just did not have a/c and the other little problems I described. It does appear whoever owned it before me was mucking around with the wiring since there is electrical tape around some of the wires, but was running until MCUs were swapped.
#4
If you think a good mechanic is expensive, try hiring a bad one
Re: Possible MCU and ECU problem
The car was running fine until I swapped out the fuse panels,
Did you loosen any grounds to get it out?
Check both fuseboxes (dash and engine compartment) for any blown fuses?
the screen on the scanner flashes rapidly, icons on the dash do the same and I hear the rapid clicking noise from behind the dash.
In the OBD plug under the dash, terminal 16 gives the scanner battery power and terminals 4 and 5 are the grounds.
Can you test to see which of these is pulsating?
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The only thing I did before taking out the panel was to disconnect the battery. I am fairly certain that I plugged all of the connectors back in securely and even looked for any loose wires in each connector. I will double check all of that again. I don't think I could have crossed any of the connectors, aren't they all unique?
How do I test the OBDII connector pins under the dash? I have a multi meter, do I check for voltage and/or resistance? Yes, it is a rhythmic, rapid clicking sound and light flashes. Also, I did not loosen the ground wire.
Also, I did not notice any blown fuses, but will double check all of them.
How do I test the OBDII connector pins under the dash? I have a multi meter, do I check for voltage and/or resistance? Yes, it is a rhythmic, rapid clicking sound and light flashes. Also, I did not loosen the ground wire.
Also, I did not notice any blown fuses, but will double check all of them.
#7
If you think a good mechanic is expensive, try hiring a bad one
Re: Possible MCU and ECU problem
Probably.
....
DO NOT try to test any terminals other than 4, 5 and 16.
Charge the battery, then attempt.
Double check your work done. Yeah this too.
How do I test the OBDII connector pins under the dash? I have a multi meter, do I check for voltage and/or resistance?
Charge the battery, then attempt.
Double check your work done.
#8
Re: Possible MCU and ECU problem
2001 so its a 7th gen sohc 1.7?
Mine did basicaly the same thing, car had a viper alarm even the last owner didnt know about. the siren n alot of it was cut out so youd never know it was alarming
also door switches go bad, along with the harness between the door and body
Is the ac switch lighting up in the dash? cause if it is ide try taking the ac clutch apart and cleaning it
Mine did basicaly the same thing, car had a viper alarm even the last owner didnt know about. the siren n alot of it was cut out so youd never know it was alarming
also door switches go bad, along with the harness between the door and body
Is the ac switch lighting up in the dash? cause if it is ide try taking the ac clutch apart and cleaning it
Last edited by MiniMi; 05-25-2015 at 06:47 PM. Reason: not done
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Yeah, it's a 2001 1.7 SOHC. I think it had something installed at one time, a lot of electrical tape under the dash. I took some tape out and found a solid green wire and solid black wire just twisted together.
The light on the a/c button does come on but neither the a/c radiator fan nor the compressor would come on. I will take a closer look at the a/c clutch another day. Going to try to recheck all of my connections to the fuse panel...again. If I can just get it running again, I am going to take it to a guy to get him to troubleshoot the wiring.
The light on the a/c button does come on but neither the a/c radiator fan nor the compressor would come on. I will take a closer look at the a/c clutch another day. Going to try to recheck all of my connections to the fuse panel...again. If I can just get it running again, I am going to take it to a guy to get him to troubleshoot the wiring.
#10
Re: Possible MCU and ECU problem
Not sure whatt the green n black wire r for, if u have an alarm or remote start it would usualy be in the drivers kick panel
ac rad fan wont come on with the ac switch
Just for fun clean your thermostat housing ground
ac rad fan wont come on with the ac switch
Yeah, it's a 2001 1.7 SOHC. I think it had something installed at one time, a lot of electrical tape under the dash. I took some tape out and found a solid green wire and solid black wire just twisted together.
The light on the a/c button does come on but neither the a/c radiator fan nor the compressor would come on. I will take a closer look at the a/c clutch another day. Going to try to recheck all of my connections to the fuse panel...again. If I can just get it running again, I am going to take it to a guy to get him to troubleshoot the wiring.
The light on the a/c button does come on but neither the a/c radiator fan nor the compressor would come on. I will take a closer look at the a/c clutch another day. Going to try to recheck all of my connections to the fuse panel...again. If I can just get it running again, I am going to take it to a guy to get him to troubleshoot the wiring.
Just for fun clean your thermostat housing ground
#11
Re: Possible MCU and ECU problem
sounds like a couple simple things making the big problem, hondas are made by angels in heaven so its usualy simple,
start with all the free and simple things.
quadrupel check fuses and grounds,
start with all the free and simple things.
quadrupel check fuses and grounds,
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