I just bought a 2006 MMH. Im not sure if all is functioning as it should. yesterday afternoon it would not go into EV mode. The outside temp was in the mid to upper 80's. I was in heavy traffic at times. This is what I have observed: in the morning it will shut down at stoplights and such. I have no warning lights or messages. I can here the battery fans running loud when its hot,also the rear A/C line is very cold sometimes other times when its hot out the line isn't cold and I hear the battery fans running loud.

When i checked the gauge diagnostic (hold the trip down and start) its shows no DTC codes and the bat showed 43 at its hottest in the afternoon, at that time I was getting very little assist. I drove on the freeway in light traffic with the A/C on the non forced ice mode. It took 25-30 min for the bat tem to come down 1 degree. I have the navigation display. I do not have a Scangauge yet.

Also I checked and replaced the battery filter and noticed whenever I check the blend door it is closed, I have never seen it open. I have checked it frequently car hot or cold running or not and its always closed.

Is this normal because of the heat? also if the rear A/C door is stuck closed due to the actuator will there be a light?

 

If 43C or 110F is what your battery temperature is, your A/C is not cooling enough. The blend door is not your problem. If the A/C is working properly, your MECS pump is most likely not working.

Gary

 

I was under the impression that the mces pump is for coolant only. There is no coolant line running to the back, only ac lines. So the problem would either be ac related, vent related, or fan related.

 

43C for the battery temp is definitely not normal! I would maybe guess that the valve that sends freon to the rear A/C unit is not working some or most of the time. Or maybe the compressor is wearing out. When the battery is hot, try driving with the front A/C turned off and see what the battery temp does. If it comes down slowly but steadily, then probably the compressor is wearing out. If it doesn't drop much or comes down erratically then probably either the control valve to the rear A/C or the rear expansion valve is flaky.

 

Sorry I meant A/C refridgerent lines. I drove it today pretty much same conditions but had the a/c off 95% of the time and the car ran great shut down into EV mode all day. I was super busy and wasn't able to monitor the batt temp but it ran really well. So compressor, charge levels, exp valve or switching valve?

 

From that I would say low on freon or weak compressor. Seems like it can cool down the car or the battery, but not both.

 

UPDATE: So i took it to a mechanic, they vacuumed out the system and pulled vacuum for 20 min or so, didn't show a leak. they refilled they system and found it to be about 1/2 lb. low. Felt really cold when I left. I unfortunately however am still experiencing the battery overheat issue.
I have also noticed that when its around 95 out it will not cool at idle only when the engine temps are around 2000 rpm and above, then after that it cools really well and the battery temps start to very slowly drop.
Im wondering if its a weak compressor, the mechanic stated the pressures on the high and low sides looked good, so I don't know.

 

It is interesting you mention 2000 RPM. At temperatures above 96F, my FEH will take the RPM to 2000 under any acceleration pedal. I guess they knew that the A/C would not cool effectively below that under high temperatures.

The only way to stop the behavior is to turn off the compressor... not likely at those outside temperatures!