I have been having a "random " battery drain . I can drive the car with no issues at all and it will fine for days . Then I park up in the garage and the next day I have to jump start it to get to work and again to get home . The car is charging ok . I have tried unplugging various things and when I think ive found the fault , it happens again . Its been suggested its a sticking relay - which makes sense - but ive no idea which one . This has been going on for about 2 months now and im at the end of my tether . My car is an 2002 Astra Coupe 2.2 . I have op com . Can anyone please help as its so unreliable im thinking of getting another car !
Battery Drain
- Thread starter Tigercat
- Start date
Yes as this was on the car when i bought it . The old battery is the one I use to jump it the morning .An autoelectricion checked the drain and thought it was better than a normal car !
Well it charges at 14.1v and it only happens with the engine and ignition off . I did think of that though and opcom gave no fault code for it . I went into opcom searching for faults and in the power steering section I found C1550 - replace ECU and C1523 battery voltage low . So does that make the ECU faulty or is showing fault code because the of the low voltage ?
Going to take it to an auto electrician . He suggested a few things when I was booking it in , and 1 of them was the radio . So I unplugged it at the back and the following day it started first time . It did again the next day , so I thought it could be the radio , but couldn't see it draining the battery as quickly as it was happening . Anyway car started fine this morning , but was dead after work . So its not the radio after all . Random 
Don't think its loose earth as its charging at 14V . The earth by the top suspension mount is not loose . I noticed yesterday on the way to work and on the way home the MFD was showing 34.5 MPG solidly . This didn't register till I noticed it again this morning . I disconnected battery at work (so I could get home ) which has reset ECU and MFD is working fine . Does this mean its a random ECU fault ?
Having to jump the car to and from work this week , I decided to disconnect the battery when I got to work yesterday so I didn't have to rely on getting a jump from someone . As the car was disconnected for about 10 hours , the ECU would have reset . The car started ok this morning and again some 10 hours later . Im now thinking its ECU . Is there an easy way to find out or check ?
had the same issue with my old coupe..... could drive it from work to home... turn it off outside the house, open the garage, go to restart and it wud be dead... jump leads on it and wud start fine..... i just replaced the battery leads and earth leads and it cured it
Update , I have found that when the battery has gone flat and needs a jump start . I take it to work and disconnect the battery , reconnecting to get home . This resets the ecu and the car will behave as normal for about 2 weeks . Then I repeat the process over again . As this is the only difference I feel that its a faulty ECU . Can anyone point me in the direction of someone that can check/reprogram it ? thanks
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