About a week ago, we had really wet weather and I had let the car sit on an almost empty tank of gas for a number of days without driving it once. It started just fine but was sluggish driving...I tanked up and took it on the highway and after about 15 minutes the check engine light and IMA light both went on, at about the same time.

My mileage in city driving has dropped (down to 35mpg from about 42mpg). The car still drives just fine though, and still gets the same mileage (about 55-58mpg) on the highway.

I was thinking of taking it to the dealer, but I had to get somewhere yesterday, and I was driving about an hour and a half ride each way, on some hilly country roads yesterday. I noticed that it seemed to be having trouble calibrating how full the battery was...it would suddenly jump up and down.

Oddly, as I drove it up and down the hills and drained / recharged it a few times, the problem seemed to go away. On the way back, the battery gauge seemed to be working as normal again, my mileage went up, and mysteriously, the IMA light turns off.

Check engine light is still on. Thoughts? Should I take it straight to the dealer? Wait on it a little more? The car is a 2003, and has been in excellent shape and has 76,000 miles on it; I bought it used at 59,000.

Thanks in advance for any input!

 

Hi,
In regards with the IMA light, I would imagine that simply switching off the IMA battery (switch is behind rear seat on the battery unit) starting the car using the normal starter motor, then turning off and swithing battery back on would 'reset' but It wouldnt surprise me if Honda has some sort of failsafe software that means it has to go dealers to be reset.

The engine managment light is more simpler. That SHOULD be purely a sensor reset or perhaps disconnecting 12v SLI battery and reseting ECU briefly. That has always worked with me on 'normal' cars where it has been left stood or it has run out of fuel (once happened on a peugeot, ran out of fuel, check engine light came on, re-filled tank, car ran fine but light was still on. so simply disconnected battery ~make sure its unlocked first or the codes will be lost~ then re-connected. Light went out car ran fine, think it was simply a warning for possible damage to the cat, which can be caused when a car runs out of fuel.

The other way is for a full check through the OBD, which will tell the dealers or garage the code and thus the fault.

Hope any of this helps.

 

The IMA light is off...I read the manual and it said that it takes 3 days of driving the car for the check engine light to go off, if it has come on erroneously (such as by a loose gas cap, etc.), so I think I'm going to drive the car a little more and see if it goes off on its own...and also see if I continue to get low mileage in city driving.

If the mileage in city driving stays under 40mpg esp. on warmer days (cause it's always lower than that on cold days in winter when it's not warmed up yet) then I think I'll take it into the dealer.

Thanks!

 

If the IMA light comes on, meaning that the IMA computer has detected a fault in the IMA system, the check engine light will also come on. If the OBD is checked for codes the check engine code will probably say something like "check IMA system". The IMA battery symtoms you describe sound like there may be a problem with the Hybrid battery. If so the IMA code, which will still be present in the computer even if the IMA light has gone out, will be "Hybrid battery deteriation" or "Hybrid battery overheating".


Also removing the 12 volt battery cable will erase all fault codes including the IMA codes.

I know all this because the IMA battery in my 2004 HCH with 200K miles is failing. I have been researching what to do. So far the options are: $500.00 for a used battery from a junk yard, $1000.00 to rebuild the battery, $2500.00 for a new battery, $3100.00 for the Dealer installing a new battery. Removing/Installing the Hybrid battery is a job that the average DIYer can do.

 

This post worked perfect form me. My 2005 Honda hybrid ran out of gas and the IMA & Engine lights both came on a stayed on. Removing the positive from the battery reset the fault codes. Now I need to figure out how to reset the clock. ....

 

I also have an 05 Civic Hybrid. My IMA and check engine lights came on once when I was going over a steap bridge. Everything seemed fine and lights went off the same day. Here I am 6 months later, and my lights came on again last Friday. Parked the car since I was going out of town, and went to drive it again today. IMA did not work at all, no assist, no charging, and my battery light came on to.

Took it to the dealership and the IMA battery pack is dead, and the IMA sensor was bad to. Luckily for me, Florida is one of the states that was involved in the class action lawsuit, and my warranty is not 10 years / 150,000 instead of the original 8 years / 80,000 miles. They are replacing the Battery, and sensor under warrenty.