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.

 

Can't say for Aussie versions. No problems replacing the battery on North America Fits (other than having to know your radio code).

 

I've done a little research and asked a few people, and this is how I ended up doing the battery change in my 2006 Australian VTI-S Jazz. Please don't take this post as gospel, as I'm new to the Jazz and am the furthest you can be from an expert.

- Remove old battery and replace with new one.

- Adjust clock radio to correct time (My Aussie radio has no security code, but you will want to reset that if your radio does have one).

- Reset window winder control unit by pressing driver side window down button until window is fully open, then lifting the same switch up for 1-second longer than it takes to fully close the driver's side window.

- Reset ECU unit memory by turning the ignition switch off, removing 15A fuse No.14 from the under dash fuse box for 5-seconds, then replacing it. The fuse number may vary with the model, and the legend on the back of the fuse box cover isn't much help to identify the correct fuse. Look for the fuse number that protects the ECU (ECM/PCM) in your owner's manual and you can't go wrong.

A very knowledgeable sounding contributor to alt.autos.honda advised me that once reset, the ECU unit must re-learn various engine operational parameters. He suggests that transient symptoms such as possible sluggishness, poor fuel economy or unusual idle speeds would be only temporary, and that optimal engine management would be restored after only a few days of driving.

It appears that there is an alternative method to clearing the ECU unit's memory. This involves the use of a Honda PGM tester unit. According to the official Honda Jazz/ Fit ESM literature however, the above-mentioned procedure is equivalent, yet costs AUD60.00 less! If I can save other Jazz/ Fit owners from being conned into an unnecessary and costly ECU service, then I've reached the objective of my post.

Once again, I'm no expert on the Jazz. If you feel that I am incorrect or misleading by anything I have said in this post, then please respond with your perspective. Please understand that my intentions have been of a benevolent nature, so I would very much appreciate your civility in any response.

Regards,
Tressie

 

Removing the battery resets the ECU (PCM, ECM, whatever. Honda likes to call it a PCM on auto transmission cars as it's a Powertrain Control Module vs. Engine Control Module). It goes back to factory presets. It's not necessary to remove a fuse after replacing the battery to do this.

Sometimes if there is a fault (Malfunction Indicator Light (MIL) or engine light on) , removing the fuse or disconnecting the battery will clear it. This isn't a good idea as the fault code is instrumental in solving the problem.

There may be some performance gains after the module relearns them, but I don't think they'd be measurable on a Fit. On some cars, after modifying the engine (intake or exhaust) it's recommended clearing the PCM so it starts fresh by disconnecting the battery.

Here in the states, the PCM is read every year when they do a smog check. If the battery was disconnected recently it won't pass, not because it's producing smog, but because it doesn't have enough data stored to give a valid reading.

Just drive it after replacing the battery. 60Aud to have it "attended to" is a rip off.

Check your manual if you want to be sure.

 

or just hook up a 9V battery to the battery wire unless you have a constant a/c socket. lol it will keep the constant enough for the radio and esc to remember. it's an old skool trick.

these days the ecu and radio have capacitors that can retain power for a good 3-4min.
i think your dealer is trying to screw you for more aussie dinero.

ive never heard of having to have to reset anything. the ecu will reset on its own but then it will start learning the working environment as soon as you start your engine. and if your radio resets, just reset the fm stations, etc. no biggie.

if you're unsure of doing the work, just let the dealer do it. piece of mind.