[nemystic]

After observing my LMPG do it’s annual winter drop below 75, I decided it was probably time to implement the warm air intake modification, which draws engine intake air from behind the catalytic converter.
I opened the hood for the purpose of surveying the best routing for the warm air duct. This was an initial survey, not the actual modification!
While venturing out on a short trip, within my home town, I noticed within about 1/8 mile of leaving the driveway, that both the “IMA” and “Check Engine” warning lights were on, and I confirmed that the IMA charge and discharge indicators were not functioning.
The garage temperature had been approximately 38 deg. F, and the outdoor temp. was 25 deg. F. After almost 50K virtually trouble-free miles on this car, I was justifiably apprehensive. I stopped after a mile and re-started the engine. It was a rare 12V start. In fact, it was only the 3rd I can remember. The “Check Engine” warning remained on, but the “IMA” warning was off, and the charge/discharge indicating seemed normal. I assumed that the IMA was working OK. Since then, the “Check Engine” indicator has remained on, and the auto-stop function seems to have been disabled. All subsequent starts have been “12V”.
In accordance with Murphy’s Law, this occurred on the Saturday afternoon of a long holiday weekend, with a messy snowstorm predicted to begin on Monday afternoon.
Since I don’t own a maintenance manual, and don’t have access to the diagnostic codes, I can only speculate as to what may have gone wrong.
My best guess would be a faulty outdoor air temperature sensor, but that might not explain why the IMA trouble indicator was on during the first mile of travel today.
It’s possible that I may have lightly “brushed” the temperature sensor while removing a temporary winter baffle (another modification) that had been dislodged by strong headwinds. However, the wires to the sensor appeared to be OK from the outside.
I filled the tank last night at a familiar "no-name" gas station. Could this be the infamous O2 sensor failure?
I’m not necessarily superstitious, but the thought did cross my mind that “Sputnik” may be trying to tell me not to consider any further modifications.
Without knowing the specific cause for this problem, I’m not sure whether there’s any risk to continuing to use the car with this condition or not.
I’m hoping to hear from the experts and/or anyone who may have experienced these symptoms.
Thanks in advance for your help.

 

[Insightful Trekker]

Without the codes there's no way of knowing for sure. However, there is a general rule of thumb that is *almost* always safe in regard to the check engine light. _IF_ there is no seat of the pants loss of power (and you'll have to mentally subtract the loss of the IMA) then its generally OK to drive.

What you should be worried about is any condition that is causing a misfire or over-rich condition that could overload the CAT and cause a meltdown. An engine driven under these conditions _will_ rapidly and eventually cause a secondary failure of the CAT. Read add $,$$$ to the cost of repair.

Most sensor connections under the hood are relatively tough and will take much more than a bump of the hand to loosen or damage. In fact I can't think of an exception to this statement.

AFAIK the outside air temp sensor is _not_ part of the fuel system and cannot set a check engine light code. However, it can prevent autostop from functioning if not connected.

Since we're "listening" to inanimate objects I hear the gas pump trying to convince you to stay in a higher fuel consumption mode. Even whimpering a bit given that its an Insight its up against. <VBG>

HTH!

 

[nemystic]

After another 15 miles today, everything seems normal except the CE indicator, the 12V starts, and the absence of auto start/stop. There’s no doubt that the IMA is still pulling and charging, and the fuel economy is where it should be expected to be without the auto stop. If the control drivers for the high voltage start are the same as for dynamic IMA functions, it would seem as though the problem is a faulty sensor, or the memory of some transient event that requires a reset. Subsequent findings will be posted in the interest of sharing information. I hope it won’t be expensive!
Once again Trekker, your "insight" is greatly appreciated.
As an infrequent visitor, I’ve learned to mostly ignore the “message” of the gas pumps. However, I will admit that on more than one occasion before the novelty wore off, upon noticing an unusually large gathering of behemoth SUVs and pickups, I’ve been lured into the self-serve gas station to practice my “poker face” while adding only about 2 or 3 gallons under their watchful eyes. 8)

 

[nemystic]

After several weeks of 12V starts and disabled auto-stop feature, I scanned the forum and also the maintenance manuals (thanks Mike Dabrowski).
The outdoor air temperature and air intake temperature sensors measured correctly, and the connectors and wiring seemed OK. I didn't check the high voltage ground cable.
We replaced the 2 engine ground cables after finding corrosion and more than half of the strands broken. I did find a reference in one of Yves' not-so-recent posts indicating that broken engine ground cables can cause IMA problem(s).
I would recommend that all Insight owners inspect the engine ground cables, as this appears to be a significant design limitation for this car.
(Please send PM if you'd like to see a photo.)

Finally, an EMC reset cleared the check engine indicator, and Sputnik has been operating normally for the past week. I assume that the IMA event which caused the "strange coincidence" condition was transient, and that the diagnostic record was lost in the reset.

I wish I could say that the fuel economy was back to normal, but here in New England, winter is hanging tough, with below freezing temperatures nearly every day, and about 8" of new snow today. Hopefully by May I'll be back to 80+ mpg.

 

[Insightful Trekker]

<snip>

Finally, an EMC reset cleared the check engine indicator, and Sputnik has been operating normally for the past week. I assume that the IMA event which caused the "strange coincidence" condition was transient, and that the diagnostic record was lost in the reset.
<snip>

FYI,

Clearing a code without recording it and its freeze frame data robs you of essential information the next time a MIL occurs. Some codes when they recur under certain engine parameters are _VERY_ difficult to trace without this data _history_.

A "blindfolded" ECM reset should be a method of last resort.

HTH!

 

[flunkysama]

You do know that the IMA system is covered by a 8yr, 80K miles warranty? If you are still covered, you can take it to a dealer and get it fixed for free. It might mean a brand new battery for free

A standard OBD2 code reader will not pull up IMA codes.

Also the IMA codes are stored in the IMA system and will be lost if the 12V battery is disconnected or the right fuse is blown or pulled. ECM codes (the kind you can read with a standard OBD2 reader) are saved even if power is lost.

 

[Yves M.]

Hi Flukesama,

I am no ODB expert but I had codes before. Some where IMA and others where ECM. Both are into the ODBII list. You can check at my site: http://yves.fungiart.com/pages/pcodes.htm
and check below P1440 +

I was told be a Honda tech, when I had about 5 different codes that the IMA are kept like the other codes (ODBII ECM) in the system

 

[Insightful Trekker]

Your _BOTH_ right :!:

A "cheap" code puller will only retrieve generic OBDII codes. IMA codes are "OBDII" but Honda specific and will require a puller with this slightly expanded capability.

IMA _data_ requires OEM software.

HTH!

 

[nemystic]

So, IIUC, despite the ECM reset, a Honda dealer with service capability should be able to retrieve the IMA code and related "strange coincidence" event data :?:
Please confirm or correct.

Thanks!

 

[Insightful Trekker]

IIUC :?:

I think the answer to your question is no.

AFAIK, Once a code is cleared its not retrievable through any means. Freeze frame data is cleared with the code. I think its stored in EEPROM

HTH :?: