Hello all. This is the second time I have had to replace a hybrid battery cell. I noticed that my car while sitting in the driveway the engine starts and stops constantly. I switch my readout on the dash to see the chargeing display and noticed that when the hybrid batter gets to fully charged the engine stops but the battery starts dropping. When the battery gets to the bottom the engine starts up again. Any thoughts on this?
This is normal to some extent, but it should take quite a while for a battery at high SOC to discharge with car READY just sitting in PARK (unless AC/heat/lights etc are on). If SOC is fluctuating rapidly, your battery is hosed again. Welcome to the world of "whack a mole"
I forgot to mention that when driving the AC recirculation shuts off and the engine revs then goes into limp mode. Then I pull over put it in park turn car off and when I start it up its like nothing happened. It runs fine then in about 10-20 min it will do the same thing again. Any thoughts? I will pull battery again and test cells.
Have you got any kind of scan tool to obtain the trouble codes being logged by the computers? What did you use to determine which module to replace last time? A/C recirculate mode will be cancelled on a signal from the battery ECU to the A/C control when more fresh air is needed to cool the battery. From this we can infer your battery is overheating, something you should be able to see in the several battery thermistor readings on a scan tool. Filling in the story, your car is detecting an unsatisfactory state of charge, calling for more engine power to charge the battery, finding that the charge current heats the battery excessively, changing to plan B to protect itself from overheating, and giving you limited power to limp home. It will optimistically try again if you restart it after the battery has cooled some, but you've already seen the same thing happens every time it tries again. You'll need to locate the source(s) of discharging/overheating in your battery, likely faulty module(s), and replace/repair as needed. -Chap
Another possible story is the ECU notices the battery heating right away, cancels the recirculate mode, and the reported engine revving is not a recharging attempt, but just the engine needing to supply all motive power because the battery ECU is saying "we got nothin' back here." Still means the battery needs fixin'. I guess there could be a slim chance of getting lucky and finding that the battery thermistors didn't get reconnected right and are falsely reading high or something. You'd probably be able to see that with a scantool. But it's probably more likely they're telling the truth and what's wrong is what's usually wrong. -Chap
