i see the light unfortunately !.

hi everyone, i was just wondering if anyone has had a similiar experience to what is happening to me.about a month ago upon start up(about 30 secs) the engine check light came on & stayed on. booked in with mazda & they advised me the code which came up was a low voltage code & i needed to repalce my battery!. battery is only 8 months old(ac delco with 660 crank amps) so i followed there advise & had it changed under warranty. no problems for a week then the same happened upon start up.


take two with local mazda dealer last thursday.they advised me that the reason the ecl was coming on was that when i changed the battery i did not tighten tup the terminals properly & they were loose?.to say i was no beleiving was a understatement. i have changed a few batteries in my life & never had this before(the little voice in my head was saying no way they don't know what they are doing!).started the car up this morning & you guessed it the ecl light comes on again!.


the car drives normally & on the report from mazda this was stated: checked engine light on & found


dtc: UO140,UO155,PO125 lost communication with bcm & instrument cluster probable cause from swapping batteries as the battery terminals were loose. cleared codes & tightened battery.

so does anyone have any suggestions?.luke mps3 suggests a short/bad earth.is there anything else i can check/do as i am getting p****d off as this will be the third trip to the dealer.any help will be appreciated.cheers pk mps309.ps only comes on upon cold morning start up never when driving.

It does sound like it could be an earthing problem, i would suggest you either, take it to a reputable auto electrician, buy and install a earth grounding kit, and buy a OBDII diagnostics tool / CobbAP or the like so you can clear the code yourself.

Is the cranking speed different to normal? slower when the light comes on? could be a poor ground on the ECU.

Batterys dont like cold mornings they dont put out as much as usual, I know your battery is new and has plenty of CCA for the car. Perhaps its a bit dodgy? get it tested at a battery place ( most do it for free in the hope that you have a dud and buy one off them )

ahh if i think of anything else i will let you know. r

You have a Gen 2?

I've herad strange things about the dash in the Gen 2.
Possible dash earth shortage?

hi guys,yes its a gen 2 2009 model. i will try another battery tomorrow.the car starts strong,no cranking issues with or without the light on.dash earth shortage i have not heard of that but i can pass it on to the rocket scientists at the local dealer!.i will also get the voltage checked on the alternator tomorrow. i will advise normally goes ok for a few days then on it comes, i'm hoping it something simple!.thanks pk mps309.

I would suggest a connection problem in the harnessess, pick one of the 500 connectors that they are connected or have no backed out terminals, loose/broken wires or earths. seeing as the code says lost communication with BCM start at it and work your way back towards battery? anything more then that its time for a visit to the shop to get it found

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Dont forget that these cars run a CAN system, so the fault may not actually be near these components, go over all harness connectors.

sounds like fun!.the car is still under warranty & i will pass it on to the local dealer.maybe third time lucky!.i won't hold my breath though.thanks pk mps309.

hi guys, had the car back today at mazda. they had it for half the day & the verdict from them was that the speco temp gauge i installed three months ago is the problem!.i had to use an adaptor approx 8cm long for the speco gauge sensor & the original temp sensor which went on the very top of the adaptor with the speco guage about half way down.

the explanation i received is that the original temp sensor must be screwed directly into the piping & not on the top of the adaptor as it is not reading the temperatures correctly & quickly enough being that distance away so the ecu cannot read the temps properly & it triggers the check engine light on!.so i will unistall the set up on thursday,worked fine for about 6 weeks?.i understand what they explained. maybe now that the mornings are colder about 3-4 degrees it may be feasable that the delay for the temp sensor as it takes longer for the coolant to get there & register correctly.


has anyone else have a temp gauge installed without any issues(electrical)?.i will advise in a few days so if anyone is thinking of putting in a temp gauge into a gen 2 mazda 3 mps watch this space!.cheers pk mps309.

I have a temp gauge, no problems so far, had it in for about a year now. All connections were made at the fuse box, have a seperate temp sender plumbed into the radiator hose. Hope you can sort out your problem with the cel. Cheers

hi jnt, i also have it connected via the fuse box. i will speak to the auto electrician re connecting the gauge via the radiator hose.thank you very much.ps is it a probe into the hose in your set up?.

I have a quick and very stupid question. Do Gen 2 MPS's have tempreature gauges standard? Mine only has a blue tempreature light thats usually on when i start the car. Im guessing when the car gets hot, another red light would come on but nothing saying the actual tempreature, unless the fuel gauge can show other things and i didn't know about this.

There is just a light. Like a lot of cars now. No need for a gauge, if anything happens, the car will go into limp mode before you notice anything on the gauge.

hi bd581,when the guage works it is very accurate,the blue light disappears at 50 degrees celius.i will have the guage sender unit refitted into the cooling systems that does not affect the ecu.i am old school & like to see what temp i am driving at. i know the technology is there for this newer set up but i was not convinced. another member has one set up with no problems so i a awaiting info from him to do the same with mine.cheers pk mps309.

---------- Post added at 07:15 PM ---------- Previous post was at 05:19 PM ----------

hi, the mps gen 2 2009-current do not have a water temp gauge.they have a blue light for low water temp which turns off at about 50 degrees celius & a red one will come on when you have a engine that runs hot.the fuel gauge is just the fuel gauge.cheers pk mps309.

Quote:

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Originally Posted by my red mps309

hi jnt, i also have it connected via the fuse box. i will speak to the auto electrician re connecting the gauge via the radiator hose.thank you very much.ps is it a probe into the hose in your set up?.

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Hi the adaptor I used is from Prosport its like the one pictured,

hi everyone, i just wanted to update you on my temp gauge reconfiguration which i finished on tuesday.no more check engine light coming on.thanks to help from jnt a 30-32 mm t peice adaptor was used cutting into the radiator hose infront/below the air box & gauge works very well( about 80 deg c day driving).so if you want to put in a water temp gauge you need to use a t peice radiator adaptor not a t peice adaptor as i first did,the length is too long to register the temps to the computer which caused the check engine light to activate.once again thanks jnt for all your help on this one!.

damn! I got the engine check light on this morning.
can I still drive it or leave it till Monday and send the car back?
I just had the car serviced last month !!! how come !!!!!

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Quote:

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Originally Posted by my red mps309

hi everyone, i just wanted to update you on my temp gauge reconfiguration which i finished on tuesday.no more check engine light coming on.thanks to help from jnt a 30-32 mm t peice adaptor was used cutting into the radiator hose infront/below the air box & gauge works very well( about 80 deg c day driving).so if you want to put in a water temp gauge you need to use a t peice radiator adaptor not a t peice adaptor as i first did,the length is too long to register the temps to the computer which caused the check engine light to activate.once again thanks jnt for all your help on this one!.

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Just saw this post today, no problem for the help, thats what great forums like this are for. Great to hear that everything is going ok with your car. Cheers. :2thumb: