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Battery flat causing issues

porscheski

Well-known member
Joined
13 Dec 2013
Messages
445
My 996 tiptronic 2003 car has been waiting for the exhaust to arrive before being fitted and the handbrake rectified for the mot. It's been unused for three weeks. The battery is 18 months old but was completely flat and discharged. My heavy duty booster pack on it only just fired it up to take to the garage.
The exhaust is on and the mot passed but on collection the car threw up a tiptronic gearbox warning on the dash in red? Google said it needs a fully charged battery- I'm taking this one back under guarantee as it hasn't held a charge twice in six weeks- then needs to have the battery reconnected and disconnected for five mins.
Then run the car for a good trip to reeducate the gearbox......
Apparently the car says on the code reader it has insufficient voltage for the tiptronic.car drove home fine this evening and I'm changing battery on Saturday. Does this sound right? It's only my local garage but these two guys are Kenyan and can fix anything I ever took to them in thirty years. Competent blokes.
 
The battery will need changing, going flat kills them in no time. Flat batteries can cause all sorts of odd behaviour.

MC
 
I,m just going to break it down a little ..

Flat battery - it can have an electrical discharge , it can have a failing alternator so not much charge in it when left or it can have a failed battery .

Battery can easily die if left to go totally flat .. even just once .

So the above needs checking first for the Battery fault .

You have a fault code for low voltage on the tiptronic and i assume this is the control unit .. it will go into limp home mode as soon as the car is started if its a permanent fault .

The car alternator will supply enough voltage for the tip cu when running so that kind of rules out battery but not alternator .. i would expect that you would have other symptoms if it was the alternator though .

First check after the battery list would be to measure the Actual voltage at the tip cu and the earths .. then its onto the input / output voltage for the valves inside the gearbox .. this all depends on what actual fault code you have so ill not go into that for now .

Start with the battery .. charge it and check it for dead cells would be the first thing then check charge rate and a discharge check .. your garage can do this , then if needed move onto the tiptronic fault .
 
Thanks chaps, I will be onto it Saturday morning. New battery and a check of the voltage from the alternator.
 
Changed the car battery for a brand new one. The battery is charging so i presume my alternator is ok. Dash says charging and multi meter confers.
Is there much under the car -earth leads/straps for example- that the garage may have disturbed when they fitted the new exhaust? It was a rear bumper off job but the garage claim there is only a number plate lamp wire involved when removing that.
Disconnecting the battery i guess resets the electrical systems much like turning on and off your home computer?
 
There is an engine earth lead but they wouldn,t have touched it .. problems with that are normally starer related .. ie it spins over very slowly .

Youll need to reset windows .. raise window , release window switch then hold in the up position for 5 secs .

Throttle and ign on for 30 secs but dont start or touch it .. this will learn anyway though .

Radio code if needed .

Short drive for everything else .

Repost if the tip fault comes back with what code it is please .
 
The car still has the tiptronic warning on the dash and is still stuck in limp home mode. I don't think i was that clear? Does the ignition on not starting it clear a fault light please?
 

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