Hi,


Bought a car, on the ride home the IMA light came on, 5 minutes later the CEL came on. Turned around and took it back to the dealer so they could fix it.

They are telling me its the IMA control module which went bad, but after replacing that the IMA light was still on so they had to take it to Honda for a software update.

I thought the update was only for 2nd generation cars?
Is it just that they needed to clear the codes twice and nobody told them?

I'm frustrated because the car performed acceptably even with the dash light lit up (actually I think i got a little *more* performance after the recal which triggered the IMA light) and now im fearing that the system will be nerfed and the car will be slow as ***** with equivalent to non hybrid mpg

Any inputs would be appreciated.

 

I am not aware of any patches similar to the HCH2 patch concerning battery performance. And on that subject, it's a great patch. It manages the battery almost the same way the prius does. If it "nerfs" your car, it's because your battery is already deteriorated, and it's hitting the more conservative limits.


The only HCH1 patches that I'm aware of are the patch to correct premature P0420 cat failures and deletion of the PTC strip circuit from the IMA battery sometime mid-2004. Note that the PTC deletion patch will ALWAYS show IMA and CEL. It will NEVER allow IMA function or NOT show IMA light and CEL.


It is possible that the control module (can't remember if it's BCM or MCM) is a mis-match to your pack, i.e., your '05 would need the patched module (assuming original battery). If they put one on from an 03 or early 04, you would get a code due to the control module expecting something on the PTC circuit, but the pack is not supplying anything on that line. Conversely, the patched module expects NOTHING on that circuit, and if mated to an older pack, which provides something on that line, it codes.


Once sorted, you can clear your own codes and force an IMA charge by disconnecting your 12V for 30 seconds, reconnecting and then charge at idle until the SoC gauge goes full. You might want to try this 3 times consecutively. The 3rd time will terminate charging almost immediately.


EDIT: Dealer is wrong. Your battery is bad based on the description in your other thread, and they are trying to avoid coming to that conclusion.


EDIT2: Honestly, given the circumstances, I would ask for a refund or agree to a reduced price in the $1000-1500 range.

 

Why did they release a broken patch like that? If the CEL is on the car will not pass smog in CA and probably a lot of other states.

 

It's very easy to criticize something one doesn't understand. I don't pretend to understand how they program it or any logic/circuit limitations. The limitation may have to do with the hardware, and they don't want to go replacing ECUs outright.


Cars were manufactured and sold with the proper configuration. The problem only manifests itself when an aftermarket or OEM battery is installed by a non-Honda entity/individual, and they fail to follow the TSB (patch it and cut the sensing wire) or spoof it (install 20-30R resistor in the circuit to appear that the PTC is active on an older ECU). OR if the ECUs are swapped. As I see it, from Honda's perspective, patch is just fine. TSB provides the instructions to address it.

 

I was thinking the same. They are trying hard to not admit that the dealer who wholesaled it to them stuck them with something that had had the ECU reset.


I don't know how much negotiating room I have on number 2... but I was thinking they should at least go half on a battery.

They said they took it to Honda to get that patch, I'd be very surprised if Honda didn't outright tell them "Its the battery. Stupid." In that case I'll have to see how honest this guy is.

 

Now they said Honda told them the car needs a new resistor because the non honda dealer replaced the IMA control module...
Does this mean cheap aftermarket IMA ctl module was installed?

I'm very confused that honda didn't pull the codes and immediately say it's the battery.

 

My point - it is hard to imagine a situation where installing a patch that permanently sets the CEL is something a CA owner would ever willingly choose to do. It is also hard to imagine why a shop in CA would install this because the owner is going to be mad and might well sue them if they do not uninstall it. In CA a car cannot pass smog that way, there are no exceptions - if the CEL is set, it fails. If it cannot pass smog it cannot be (re)registered or sold legally.

Even in a state with looser smog laws having the CEL permanently lit would be undesirable since it would mask real problems that would also light the CEL. For instance, a slightly wonky cylinder due to a failing plug or injector.

I just don't see when the patch would be a better choice than making the minor electrical modifications needed to deal with the underlying issue. I had to cut that wire for my replacement battery, and it was a trivial mod which took 5 minutes even though I had never done one like that before (not counting the time to open up the car to access the wire - but that would be work done in any case when changing a pack.)

 

Because an ECU mismatch does not indicate bad battery.

I really don't know what you're on about. It seems like you understand, yet don't understand the issue.

Compliance with the TSB does not result in a CEL. Patching is not done without complying with the TSB (which includes the wire cut). A CEL results from a mismatch between ECU and PTC circuit requirements when done outside a Honda dealership.

ALL of this is happening because a non-Honda dealer sold a car with a failing battery. They tried to fix it with an ECU trying to avoid replacing a battery. They put an UN-patched ECU in.

 

Is what you are saying basically: The ECU can't "talk" to the battery because of the mismatch, this is why its not giving the mismatch error AND also the bad battery code. ?

Ok, so when they patch the ECU and install this missing resistor ... then it will indicated the bad battery? (sooner or later...?)

What resistor are they talking about? All I could find on google was it seems to be something with the blower motor for cooling the various non-seat items enclosed in the rear seat, or possibly some workaround that plugs into the control module.

 

complete sidenote, why wont the site let me add to my garage? i mean it does have what I own in the upper right above my post count so its redundant I guess but... still curious.
I get a 403, forbidden, error.