Hi All,
SHVCS has happened twice again since my last post. The car is currently in that state. I suspect winter temps getting below -10C had something to do with it, but I'm not sure.
The first time, these were the codes that showed:
1 - P0AA6 - Hybrid Battery Voltage System Isolation Fault
2 - P0CD2 - Charge Port Door Unlock Control Performance
3 - P1FFF - DTC P1FFF is an umbrella code
The second time, it had these:
1 - P0AA6 - Hybrid Battery Voltage System Isolation Fault
2 - P1E00 - Request illuminate MIL (check engine light)
3 - P1FFF - DTC P1FFF is an umbrella code
I'm putting together a troubleshooting list, so please advise me however you can. Also, if you could point me to any other threads where I should also post this, that would be great as well.
Troubleshooting list so far:
1 - Read and record the diagnostic measurements for isolation resistance, and other readings about the high voltage system. Can I do this with my 2-year subscription to SPS? I'm assuming it's possible due to the readings I've seen posted. I'll see what options are presented in the UI...
2 - Check for moisture in the trunk and battery pack. I saw this video about a gasoline-electric hybrid SUV getting moisture in the battery pack:
https://www.youtube.com/watch?v=lH-CjdWMmWQ
I charge outside, with the charger in my trunk, very often. I may have to stop doing this if I can see water damage. I've heard mention of a drain plug on the battery which can be removed and put back in, and if I stick a rolled up paper towel in here, I could check for moisture or coolant. Has anyone located this drain plug? I can only see plates and shields on the bottom of the car.
If I see moisture like this, I'd have to try to stop it getting into the pack... which may be hard, but I'd still know the heart of the problem.
3 - Calibrations. Is there a calibration setting that I can manipulate when the ECMs are programmed? If I find that they are not set to the newest, I would reprogram the HPCM2 and BECM with the newest and then see how long it takes for the SHVCS message to come back.
4 - Upgrading the firmware on other modules. quantumorbit stated earlier that he updated a list of modules: Battery Charger Control Module, Body Control Module, Coolant Heater Control Module, Engine Control Module and Electric Power Steering Control Module.
I only reprogrammed the HPCM2 and BECM, so that is one delta between his process and mine. I would upgrade all of these to the latest version, then see how long it takes for the SHVCS message to come back.
5 - Start and stop the car with the coolant sensor in different positions to see if that wiring is provoking this. I don't expect this to have any effect, because the P0AA6 code indicates a isolation fault in the 300V battery... not a low coolant level.
6 - Replace the 12V battery. I have not yet replaced this... shame on me. I have seen a 'service theft deterrent system' after reprogramming the 2nd last time, but not on the last time. The only thing though - the vehicle can turn the engine over fine, I don't hear any noise like an ICE car starting when it's very cold. If nothing else seems to help though, this is worth a try despite the cost.
If the above steps yield no useful information, I guess I'd have to assume it's a problem with the wiring or the 300V battery. At that point I'd have to ask, does anyone know who is the best dealership in Ontario for Volts? I'm out of warantee b/c I'm over 160,000km in Canada. It's worth a drive if they are quite knowledgeable and I wouldn't be just throwing money away dealing with them.
Any advice about this approach would be awesome. Thanks again everyone.