Check Engine light on Honda Civic Hybrid: IMA battery temperature sensor

2008 Civic Hybrid. IMA battery light and Check Engine light are both on whenever there's somewhat high electric load such as running AC and with head light on. IMA was replaced last year so it's under warranty. But the dealer says its accessories such as its temperature sensor are not part of the warranty. If I bring the car in, $104 diagnostics fee will be charged up front.

> wrote:
>2008 Civic Hybrid. IMA battery light and Check Engine light are both on whe=
>never there's somewhat high electric load such as running AC and with head =
>light on. IMA was replaced last year so it's under warranty. But the dealer=
> says its accessories such as its temperature sensor are not part of the wa=
>rranty. If I bring the car in, $104 diagnostics fee will be charged up fron=
>t.
>
>Using scanner to check the Check Engine code. It's P0A9E "Hybrid Battery Te=
>mperature Sensor A Ciruit High". According to a Youtube video, it doesn't l=
>ook that hard to replace the sensor. But a few shops I call (not dealers) a=
>ll say they don't work on it.
>
>Any suggestion is appreciated. Is it really the IMA temperature sensor?

Maybe. Or maybe the battery is overheating. Or maybe there is a connector
problem. The fact that it's coming on under a high load would make it more
likely that it's actually a battery issue. Still, you can swap out the
temperature sensor and see, or you can stick a thermometer in the battery
pack.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

wrote:
> 2008 Civic Hybrid. IMA battery light and Check Engine light are both
> on whenever there's somewhat high electric load such as running AC
> and with head light on. IMA was replaced last year so it's under
> warranty. But the dealer says its accessories such as its temperature
> sensor are not part of the warranty. If I bring the car in, $104
> diagnostics fee will be charged up front.
>
> Using scanner to check the Check Engine code. It's P0A9E "Hybrid
> Battery Temperature Sensor A Ciruit High". According to a Youtube
> video, it doesn't look that hard to replace the sensor. But a few
> shops I call (not dealers) all say they don't work on it.
>
> Any suggestion is appreciated. Is it really the IMA temperature
> sensor?

Measure the resistance of the sensors and see what they show. The code
is telling you one is reading as a higher resistance than it should. So
if you check circuit A and it reads 200K but you check circuit B and it
shows 100K at the same temperature then you have found the problem.

If it's only happening under high loads I would try unplugging the
sensor and plugging it back in a few times. Could simply be that some
crud or moisture got in there and caused corrosion which causes the
higher resistance.

--
Steve W.

On Sunday, January 10, 2016 at 8:00:03 PM UTC-6, Steve W. wrote:
>
> Measure the resistance of the sensors and see what they show. The code
> is telling you one is reading as a higher resistance than it should. So
> if you check circuit A and it reads 200K but you check circuit B and it
> shows 100K at the same temperature then you have found the problem.
>
> If it's only happening under high loads I would try unplugging the
> sensor and plugging it back in a few times. Could simply be that some
> crud or moisture got in there and caused corrosion which causes the
> higher resistance.
>
> --
> Steve W.

Thanks Steve and Scott. Unfortunately I have problem finding the way to access this thing. I can't even find a repair manual anywhere on IMA. If you have a few pages of the manual, would you scan and post here? (To be honest, my car repair experience was severely outdated. I worked on cars a lot when I was a college student many years ago.)

Yong