Thanks Mark

Yea I have a CVT but it's always been my thought that I can still drive in relatively flat terrain with a weak IMA...maybe with only two people in the car too...I know power will be compromised but from the performance specs for this car, the IMA adds 13 HP to a 99HP engine so it's not like it becomes a Yugo!

Tim

 

A lit IMA warning lite and a weak IMA battery are not fatal to keeping the vehicle a daily driver. WEAK is the key word here. If the IMA system decides it can no longer safely charge the IMA battery (read: IMA BATTERY DEAD), IMA 144V essentially goes off line and is evidenced by the red 12v battery warning lite on at <1200rpm. Why is for another time. I've measured the 12V battery in realtime and the 12v warning lite does in fact mean the 12V is DRAINING. And if you're running A/C and are steering (steering boost is electric - BTW) and other electrical loads, your DRAINING FAST. And I'm sure you noticed, the 12V is relatively small, so if it drains to the point it cannot run fuel/ignition, the vehicle dies and your dead in the water.

Now, I found I COULD continue to drive by keeping RPMs up. And at stop lites, I would shift the CVT into neutral and rev to 1500 or until 12v battery lite went off and turn the A/C off. I also measured in realtime this voltage and it would charge and regulate to no more than 14.3 volts. This is a good thing. Just keep in mind, when the IMA battery is DEAD, it is then the 12V battery that starts the car using a backup starter motor.

Now, I personally would not drive daily with a DEAD IMA battery, and immediately set about rebuilding (charging/balancing) my IMA pack. It took 2 1/2 weeks but now NO worries and NO warning lites!

 

Wow you rebuilt your battery pack? That's awesome, i never even assumed that was possible by the consumer. Do you have a blog or write-up on how to do this?

tim

 

I wouldn't recommend rebuilding your battery unless you're familiar with some of the concepts surrounding battery packs. Or at least have a very, very strong desire to learn.

It's also getting harder to find good subpacks. Replacement with new cells is the ultimate solution.

 

I'm wondering what the IMA codes and subcodes are that have allowed you to drive the car with the CEL and IMA lights on for such a long time. I recently got a P1449 code on my 2003 Civic (standard) but they didn't give me the subcode so I'm not sure which one of the four it is and also not sure which of the four is basically driveable until the battery fails and which are not - leading to the case of 12v battery failure and potential stranding. Any thoughts would be appreciated!

 

same problem here, CEL and IMA light on, HCH I 2004 CVT, 105,000 miles.

Codes pulled (thank god Mexico has a place called Auto Zone nowadays):

P 1600, P 1433 (IMA battery wear I guess).

Car worked fine however, charged, discharged IMA, assited-deassisted, 12 V battery light NOT on.

I disconnected the 12 V battery just 5 mins ago to look if its placed properly etc.

After reconnecting the 12 V battery, the lights went off.

Just a software glitch? - it rained heavily over here the last 5 days, today is the first sunny day and a bus pretty much splashed the car 2 days ago when driving through a huge wet spot (which he did not have to drive through, but that's another story of the joys living in latin america).

 

I have a 2004 HCH with 220K miles and this 12V battery thing is annoying the heck out of me. The problem always initiates on ignition and is very sporadic. If you start the car and the battery light flashes then goes out and stays out (as it should) you are fine, but if it comes back on your driving experience is a nightmare. It's almost as if you have a bad altenator, but the car never shuts off completely it just operates vith very low voltage throughout the system. radio cuts out, transmission doesn't work properly (very jerky) and acceleration is annoyingly slow from a standstill (feels like you are stalling out). After about 1200 RPM the light goes out and it feels almost normal and on the highway (cruising) it's like normal. I can't seem to figure out what triggers it to get into this "low voltage" mode. I know when you disconnect and reconnect the battery it resets the system and your next start up is usually normal (with no 12V batt light on). Strange and weird stuff! I was gonna get another HCH, but too many issues when the IMA battery goes bad!

 

I also just put in a brand new top of the line 12v battery Tuesday and this is still happening about 60% of the time now. The frequency of the "low voltage" mode is slowly increasing. I guess I will check for bad battery or ground connections later.

 

Hi Mark. Is you CEL and IMA light on as well? Thanks

 

Yes they both are