Changing battery

[Madmonkee]

B7 Rs4, will i get away with putting another battery on the front jump points whilst I swap out the battery? Or will it need coding regardless? Cheers all

[PetrolDave]

B7 Rs4, will i get away with putting another battery on the front jump points whilst I swap out the battery? Or will it need coding regardless? Cheers all

No coding needed on the B7 when you change the battery as it doesn't have a battery management system, only MMI cars (i.e. B8) need coding when you change the battery.

But you will get a G85 yaw sensor fault and many control modules will log fault codes, which you'll need to reset.

[Madmonkee]

Cheers Dave, easy to reset the sensor, i have Vagcom.

[Madmonkee]

Why would this happen when the system is kept "alive" The battery never went dead, it just started playing up when it got cold, so swapped it out.

[PetrolDave]

Why would this happen when the system is kept "alive" The battery never went dead, it just started playing up when it got cold, so swapped it out.

Either the battery terminal voltage is low because of the low temperature or when you crank the engine with a battery that's on its way out the high internal resistance of the battery combined with the high current drain will drop the terminal voltage below the low voltage threshold of some modules - which will make them log fault codes.

[Ian_C]

Why would this happen when the system is kept "alive" The battery never went dead, it just started playing up when it got cold, so swapped it out.

Either the battery terminal voltage is low because of the low temperature or when you crank the engine with a battery that's on its way out the high internal resistance of the battery combined with the high current drain will drop the terminal voltage below the low voltage threshold of some modules - which will make them log fault codes.

This is what happened on my B6 - as I turned the key to turn the starter motor, everything reset. RNSE wanted code, clock flashed 00:00 hours 01.01.2000 (or similar) etc etc. Only thing on the dash that lit was clock and mileage - plus DIS lit up like a Christmas tree saying 'NO OIL'. No speedo, rev counter, dash lights etc etc. Immediately hooked up to a battery charger, and managed to get the car started after charge, but the damage was already done.

If you have jump leads, it can only be a good thing to swap batteries without ever disconnecting the power from the car

[Madmonkee]

Update: jump leads onto front jump points and a slave battery. Remove old battery, new one in, connect up. Jump leads off, all good!! Drove to work and back (45 mins each way) no errors as yet. I've not had time to plug her in to check anything hidden.

[Ian_C]

Excellent, good stuff!