ECU issues when replacing battery - Jazz

Hi,

I'm the happy new owner of a 2006 VTI-S Jazz that needs a new battery, as it
only cranks over slowly. There's still some charge in the battery and the
central locking still works.

When I bought a new battery from a Honda dealer, they said I would have to
have the ECU attended to at a cost of AUD60.00 after changing the battery.
Apparently if I didn't, then my mileage would be ruined, the Earth would
come to an end, etc, etc.

I've seen some posts about resetting the Jazz ECU by simply unplugging the
unit for 4-5 minutes, and then plugging it back in. Is this what my Honda
dealer is offering for AUD60.00, or will I truly be in need of more
substantial ECU attention after the battery swap?

Tressie.

 

Disconnecting the battery resets the ECM. And that's where the alleged
problems come in.

I don't know what kind of emissions system Australian cars have, but if
it's anything like North America's, you don't have a lot to worry about
except...

1) Disconnecting the old battery will erase all the "learned" presets that
are stored in the computer. This includes idle, transmission "grade logic",
fuel trim, and all the OBD-II "readiness monitors".
These things will all take the computer a few days to re-learn, so the car
may feel "funny" for a while until the ECM trains itself. If you drive a
long enough distance, you may (or may not) notice a small drop in mileage
until the learning is complete.

2) American-market cars have security codes programmed into their radios.
If the battery is disconnected, the security code needs to be re-entered
before the radio will work again. I don't know if Australia has that too,
but your Owner's Manual will tell you.

But the ECM re-learning WILL happen, and will happen on its own, without
any fancy hocus-pocus or equipment.

 

To avoid the hassle, will not one of those devices with the lighter plug
and a 9 volt battery (or whatever) save all the setting for the short
time that the vehicle's battery will be off line?

With all the resetting that will be done on a battery change on a car
with an entertainment system, GPS, etc. the $10 - $15 charged for those
little doohickeys would probably be money well spent.

OTOH, for the AUD$60 his dealer was going to charge him for this
"service" he should get a kiss first. Service, that's what they do to
cattle using a bull, isn't it?<g>

 

Thanks Tegger and Dddudley.

Thats 2 really good posts that have both helped me to understand and manage
the situation.

Very happy!

Tressie.

 

depends if your car's outlet stays energized when the car is OFF,many cars
shut off the lighter outlet when the ignition switch is off.


--
Jim Yanik
jyanik
at
localnet
dot com

 

Jim Yanik, wrote the following at or about 11/25/2009 7:49 AM:

Whoa! Good catch, Jim. I completely forgot about that. That would be
the case on my Accord and I don't recall if the outlet buried in the
center armrest is also switched through the ignition.

I know one thing and that's that I would NOT risk swapping out the
battery with the ignition switch in the run or accessory position. I'm
not sure but I suspect that could wind up costing me more than the
AUD$60 Trespasser was about to be relieved of.

That said, if the principle of floating a charge of 9v, etc. during the
swap is valid in this regard, I suspect that there is a kit made with
alligator clips to jump between the positive cable and ground and
accomplish exactly the same thing without using the accessory power
socket (formerly known as a lighter socket<g>)

Hope it's not too late for Trespasser!

 

I have avoided the ECM problem on various vehicles I have owned by
connecting an external 12 volt power supply to the battery cables. When
the battery is removed, the cables are still receiving 12 volts so the
ECM retains its memory. Has always worked for me.

 

It's amazing that auto manufacturers have not implemented such a device,
(short term capacitor), in their designs.

This is just another reason that I drive old cars...

JT

 

Dealers have those tools expressly for the purpose of retaining radio
security/presets and ECM-learning.

But there ought not to be any sort of $60 charge (what the OP was told) for
its use any more than there's an additional charge for putting the drain
plug back during an oil change.