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civic mk9 locking and alarm and warning lights

9K views 29 replies 8 participants last post by  welly24 
#1 ·
mk9 2.2idtec alarm went off at night unlock and locked it.3am went off again struggled to turn off wouldn't relock,went out later started ok then all the warning lights came on traction control,boot open,doors open steering fail,tyre pressures,engine management,scanned it p0504 powertrain,checked braklight switch fine,cleared code ,engine management light still on rest cleared ,went 3 miles all lights back on ,scanned again p0504powertrainscanned all units no faults,if I try lock it on remote sometimes it locks but goes off after a couple of minuites,if I lock with key it locks but indicators start to flash ,it will still unlock with key and drives fine any ideas thanks before I burn it
 
#2 ·
The first question with electrical problems is always how old the battery is.
 
#5 · (Edited)
Are you sure he's talking about an aftermarket alarm? I was wondering if it could be aftermarket, but if I'm reading his post correctly, he could very well be describing symptoms of the factory alarm. But I also agree with checking the battery. Put a digital voltmeter on it when these symptoms are occurring, without starting the car, and see what the voltage is. I know a low-voltage battery can cause crazy things to happen with an aftermarket alarm. I would think it could also affect the factory one, as well.
 
#6 ·
the battery is new from honda 3 months ago and fitted by them,voltage checked in morning 12.33,and this wouldn't cause all the warning lights to be on when the car is running,with 14.1 volts ,the alarm is factory,it has been scanned 3 times and p0504 powertrain is the only code,the brake light switch has been replaced,it has been raining for a few days and this has never happened before it stopped raining yesterday and now after a few hours all but one of the faults have gone ,which is boot open this only comes on when I set off from a standstill,ive checked everwhere and there is no water in the car anywhere in the boot or engine bay,the ecu plugs have been checked and are dry and clean, is there a common earth fault maybe,the car has done 54000 miles,its not the alarm that's the main thing its the fact that all the warning lights were on but the car ran fine
 
#7 ·
#10 ·
I'm guessing the "mk9" means mark 9, or 9th generation?

The only thing that comes to mind about all the warning lights coming on is that, typically, when you turn on the key of most cars without starting the engine, all the warning lights come on so you can see that the bulbs/LED's are working. This is pure speculation, but maybe something in the car is tripping this circuit/condition even after the car is running? Maybe something in the ignition switch? Again, just guessing here.
 
#14 ·
I have checked all plugs and no water in the ecu or fusebox,there are no signs of water anywhere in the car on the carpets or any water marks on the inside bodywork,it cleared for 3 days then just started again all the warning lights are on the boot lock is locking and unlocking constantly and the brakelights are dim and flickering all the time,its been scanned and no faults show up,im putting it down to a corrupt fusebox or ecu ,but the car runs fine
 
#15 ·
Well at this point the easy thing to do is troubleshoot the brake light problem.
It's a basic circuit and if you find the problem with the brake lights, you'll likely solve the other problems along the way.

I'm surprised the person that "scanned" for codes didn't begin checking why the brake lights are acting weird.
 
#16 ·
no problem with brake lights or boot lock at the time of the scans ,at the moment the boot is constantly unlocking itself about every 10 to 15 seconds if I start the car the door warning is on but goes of if I press the throttle pedal,engine management is on constantly ,and the brake lights are flickering and sometimes flash on when parked up but work fine when running
 
#17 ·
Understood.
What I'm saying is troubleshoot the problem that you can duplicate all the time. All this could be from a faulty earth ground, would not hurt to check under the hood for loose or corroded grounding terminals.

Also, has your car been wrecked or had any recent repairs?
 
#18 · (Edited)
I am no mechanic, and I don't know if anyone has already tried this, but I Googled "Civic UK P0504" and came up with this site...

OBDII PorwerTrain P Codes - United Kingdom | BBA Reman

If you scroll down, it lists P0504 as "P0504 Brake Switch A/B Correlation". This would seem to make sense considering the brake light issues.

This may be generic information and may not be related directly to the Civic, and again, I have no idea how accurate any of this may be, but I figured I'd throw this out there.

I will also point out that, on my previous car, a 2002 Ford Escort ZX2, I started having trouble with the cruise control not working and the automatic transmission not going into "lock-up" for the torque converter on the highway. Thinking I was looking at an expensive sensor or computer type repair, I checked out the ZX2 based forum I was a member of, and I found that -- of all things -- a burned out bulb for the third (center) brake light could cause these issues. Buying a $2 bulb and replacing that burned out bulb solved the issues. Something about some sort of ground or signal that passes through the filament of the bulb. Of course, I'm not saying that's what's going on here, but with these computer-controlled cars, sometimes weird things have unexpected causes.
 
#19 ·
I am no mechanic, and I don't know if anyone has already tried this, but I Googled "Civic UK P0504" and came up with this site...

OBDII PorwerTrain P Codes - United Kingdom | BBA Reman

If you scroll down, it lists P0504 as "P0504 Brake Switch A/B Correlation". This would seem to make sense considering the brake light issues.

This may be generic information and may not be related directly to the Civic, and again, I have no idea how accurate any of this may be, but I figured I'd throw this out there.
Good find.

Maybe you should consider a career as an auto mechanic...
 
#20 ·
I did google the p code ,and joined many honda forums but no one had the same symptoms I replaced the brake light switch as the first step as that was the p0504 description,i disconnected the wiring plugs in the boot lid starting with the brake lights but the fault was still there,i then disconnected all the other plugs and all the warning lights apart from the engine management went off and the car is fine,i have since reconnected the plugs and all faults have cleared and the car is back to normal,now I have a fuse box I haven't used,maybe it will happen again,thanks for your help
 
#27 · (Edited)
My Car - 2.2 CDTi 2012 Plate
All fuses correct
Brake lights working normally

Welly24, I have what I consider to be exactly the same problem(s). It all started off with the rear centre brake light warning (not boot open), then in quick succession after a mile or so, Engine Management Light with VSA, Power Steering and Tyre Inflation warnings. Even stranger is the door ajar warning light is on constantly when parked or driving but drops off when I press the brake pedal. The P0504 code can be cleared when the brake pedal is kept depressed, but comes back immediately when released. I have no loss of systems or performance. Vehicle will not lock with the fault logged.

I have located the brake pedal switch and it still operates on the little plunger. I have a replacement switch on order but I’m getting the impression that this won’t solve the problem. I’m leaning towards some H20 (water) gremlins somewhere in the system, although I have stripped back most of the internal plastics to check for moisture. I had the same problem previously (very briefly before it magically rectified itself) and if my memory serves me right it was very rainy both occasions when the fault presented itself. Could this maybe be a possibility?

Did your problem ever come back over this past 12 months?
 
#21 ·
so ive not found any faults as such,as the brake lights were flickering all the time I stripped the tailgate and disconnected the plugs one by one and the lights stopped flickering and all the warning lights went out and the central locking started working .I used the car for a week with no problems so reconnected the plugs and scanned and cleared the p0504 code ,been using the car for 2 weeks with no problems or warning lights ,the plugs were dry with no corrosion,i removed the fuse boxes and ecu and found no water or corrosion anywhere in the car.,the car is back to normal with no faults ,aliens?gremlins or something more sinister ,who knows
 
#22 ·
Does your car have incandescent tail/brake light bulbs?
Could have a bad bulb.
Didn't think of it right away, but I seem to remember some weird occurrences on cars with LED tail/brake lights, especially aftermarket products.

As the car is working now; I'd leave well enough alone. Until such time it starts freaking out again.
 
#25 ·
i had this same problem on my 2012 EX its rainwater getting into the electrical plugs in the back get in the back and check the ceiling at the sides by the roof airbags if the ceiling is wet or showing signs of it, rip all the plastic out by the rear seat belts drivers side and all the electrical plugs behind will be soaked
 
#26 ·
here is exactly what i did:
had this exact same problem on a 62 plate EX First i had engine management light and connected the computer gave code P0504 (BRAKE PEDAL SWITCH) then shortly after ABS Light, Electric Steering Wheel and Flashing Tyre Pressure Horseshoe.
Here is how i fixed it:


First press the Brake Pedal a few times and if the brake lights work its not the Brake Switch don't even waste your time taking it out, its just a switch there is no circuitry in there (and Honda charge near £60 for a new one!!)


The next thing i did was check all the fuses with a multi meter but if everything is working in the car i would skip this.


Just go straight to dropping the back seats and get in the back look at the ceiling either side by the boot at the top by the ceiling airbags if its wet or water stained that is the issue.
remove the side plastics start with the drivers side cos this is the problem area pull the rubbers and get the plastics off be careful with the top grey plastic it pulls downwards but the airbag is above it, just rock it back and forth and it will come off .
you are then greeted with 4 or 5 white plastic wiring plugs all soaking wet!! i disconnected them all blew all the water out sprayed WD40 inside them then dried with hairdryer. I was thinking about removing the plugs and soldering each wire and insulating but its a bit of work too do that.
anyway once its all dry plug it all back together then i got some plastic bags like food bags wrapped around the wires at the top of each plug and secured with a cable tie then duck tapped over it and left the bag open at the bottom about an inch past the plug.
so basically waterproof each plug but leave the bottom open so it doesn't condensate, do all the plugs even the yellow airbag ones just pop the clip off the body, i didn't clip them back just cable tied together as the water comes down the bodywork.
do the passenger side too not much over there just some DENSO stuff and the airbag but cover them too.


Now i still haven't managed too find out where the water is coming in but i've just bought some STICK LIKE SH1T CLEAR from Screwfix so i'm gonna seal the fook out of everything around that area and hopefully it will keep the water out.


put it all back together turn the engine on and tap the brake a few times and all the lights should disappear.


happy days



mine started with the alarm going off random at first so that must of been the start of the water getting in those plugs just glad its not Gremlins
 
#28 ·
here is exactly what i did:
had this exact same problem on a 62 plate EX First i had engine management light and connected the computer gave code P0504 (BRAKE PEDAL SWITCH) then shortly after ABS Light, Electric Steering Wheel and Flashing Tyre Pressure Horseshoe.
Here is how i fixed it:


First press the Brake Pedal a few times and if the brake lights work its not the Brake Switch don't even waste your time taking it out, its just a switch there is no circuitry in there (and Honda charge near £60 for a new one!!)


The next thing i did was check all the fuses with a multi meter but if everything is working in the car i would skip this.


Just go straight to dropping the back seats and get in the back look at the ceiling either side by the boot at the top by the ceiling airbags if its wet or water stained that is the issue.
remove the side plastics start with the drivers side cos this is the problem area pull the rubbers and get the plastics off be careful with the top grey plastic it pulls downwards but the airbag is above it, just rock it back and forth and it will come off .
you are then greeted with 4 or 5 white plastic wiring plugs all soaking wet!! i disconnected them all blew all the water out sprayed WD40 inside them then dried with hairdryer. I was thinking about removing the plugs and soldering each wire and insulating but its a bit of work too do that.
anyway once its all dry plug it all back together then i got some plastic bags like food bags wrapped around the wires at the top of each plug and secured with a cable tie then duck tapped over it and left the bag open at the bottom about an inch past the plug.
so basically waterproof each plug but leave the bottom open so it doesn't condensate, do all the plugs even the yellow airbag ones just pop the clip off the body, i didn't clip them back just cable tied together as the water comes down the bodywork.
do the passenger side too not much over there just some DENSO stuff and the airbag but cover them too.


Now i still haven't managed too find out where the water is coming in but i've just bought some STICK LIKE SH1T CLEAR from Screwfix so i'm gonna seal the fook out of everything around that area and hopefully it will keep the water out.


put it all back together turn the engine on and tap the brake a few times and all the lights should disappear.


happy days



mine started with the alarm going off random at first so that must of been the start of the water getting in those plugs just glad its not Gremlins
here is exactly what i did:
had this exact same problem on a 62 plate EX First i had engine management light and connected the computer gave code P0504 (BRAKE PEDAL SWITCH) then shortly after ABS Light, Electric Steering Wheel and Flashing Tyre Pressure Horseshoe.
Here is how i fixed it:


First press the Brake Pedal a few times and if the brake lights work its not the Brake Switch don't even waste your time taking it out, its just a switch there is no circuitry in there (and Honda charge near £60 for a new one!!)


The next thing i did was check all the fuses with a multi meter but if everything is working in the car i would skip this.


Just go straight to dropping the back seats and get in the back look at the ceiling either side by the boot at the top by the ceiling airbags if its wet or water stained that is the issue.
remove the side plastics start with the drivers side cos this is the problem area pull the rubbers and get the plastics off be careful with the top grey plastic it pulls downwards but the airbag is above it, just rock it back and forth and it will come off .
you are then greeted with 4 or 5 white plastic wiring plugs all soaking wet!! i disconnected them all blew all the water out sprayed WD40 inside them then dried with hairdryer. I was thinking about removing the plugs and soldering each wire and insulating but its a bit of work too do that.
anyway once its all dry plug it all back together then i got some plastic bags like food bags wrapped around the wires at the top of each plug and secured with a cable tie then duck tapped over it and left the bag open at the bottom about an inch past the plug.
so basically waterproof each plug but leave the bottom open so it doesn't condensate, do all the plugs even the yellow airbag ones just pop the clip off the body, i didn't clip them back just cable tied together as the water comes down the bodywork.
do the passenger side too not much over there just some DENSO stuff and the airbag but cover them too.


Now i still haven't managed too find out where the water is coming in but i've just bought some STICK LIKE SH1T CLEAR from Screwfix so i'm gonna seal the fook out of everything around that area and hopefully it will keep the water out.


put it all back together turn the engine on and tap the brake a few times and all the lights should disappear.


happy days



mine started with the alarm going off random at first so that must of been the start of the water getting in those plugs just glad its not Gremlins
Sounds like a very similar possibility! But having trouble locating any moisture. Looking to park undercover and give the whole thing a blow dry!
 
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