Battery drain

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Helsbyman
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Battery drain

Post by Helsbyman » Mon May 01, 2017 9:16 am

I am reading on this and other forums of people saying the charged there battery only for it to be flat the next day. Well I have found out it is a fault on the ECU which makes this happen as the ECU holds something open and this drains the battery and only a replacement ECU will cure this fault
If you google ECU TESTING [ the name of the firm ] they can fix it. IT is a common fault
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talkingcars
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Re: Battery drain

Post by talkingcars » Mon May 01, 2017 9:49 am

There is a relay in the ECU that remains live for between ten and twelve minutes after the ignition is switched off, this is to allow the system to monitor coolant temp and run the radiator fan if need be. It isn't uncommon for this relay to stick open leaving the system live.

It isn't the only cause of rapid battery drain, the other most common cause is an interior light not switching off.
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Blackwell Bandit
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Re: RE: Re: Battery drain

Post by Blackwell Bandit » Mon May 01, 2017 5:15 pm

talkingcars wrote:There is a relay in the ECU that remains live for between ten and twelve minutes after the ignition is switched off, this is to allow the system to monitor coolant temp and run the radiator fan if need be. It isn't uncommon for this relay to stick open leaving the system live.

It isn't the only cause of rapid battery drain, the other most common cause is an interior light not switching off.
If you have a faulty alternator diode pack this can be the same symptoms, remove the large fuse in the engine bay and leave over night, if the battery has retained charge the the alternator is at fault.

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