2019 SE Sudden drop in range - battery "fixed" - still can't fully charge

[jackconn]

I normally get (got) about 140 miles range at full charge and am very familiar with range variations from ambient temp, hvac use, driving style in previous cycle, etc. Starting in roughly January, the range meter was randomly, infrequently doing weird things: suddenly dropping by 40 miles or so and one time dropping to 11 miles. It didn't occur often enough to figure out any correlations then one day I couldn't charge above about 75-80 miles. No CEL or fault codes. The dealer ran a bunch of tests and eventually found a problem with one of the battery modules. They checked with corporate who eventually said it needed battery service and the nearest certified tech was in Massachusetts (I'm in Raleigh). Three weeks later, yesterday I picked it up and didn't think much about the range meter being at about 65 (thinking was just poor customer relations to not give me a car at full charge, but no big deal).

Got home and have been unable to charge above 74 miles. UGH. Tried my L-2 charger, the 120V VW charger, immediate charging, and programmed (midnight) charging - same result. I'm hoping it's simply a matter of resetting something or a Battery Management System software update. Any ideas??

From the service ticket, they "Removed and replaced j996, j1002, j1045, and j1046, performed module addressing test and rechecked for faults while attached to vas 671001 no faults. Performed insulation test passed. Cleaned lower housing replaced upper battery housing and performed leak test passed. Reinstalled HV battery and recommissioned HV system. Road tested 5 miles and charged battery."

 

[f1geek]

I normally get (got) about 140 miles range at full charge and am very familiar with range variations from ambient temp, hvac use, driving style in previous cycle, etc. Starting in roughly January, the range meter was randomly, infrequently doing weird things: suddenly dropping by 40 miles or so and one time dropping to 11 miles. It didn't occur often enough to figure out any correlations then one day I couldn't charge above about 75-80 miles. No CEL or fault codes. The dealer ran a bunch of tests and eventually found a problem with one of the battery modules. They checked with corporate who eventually said it needed battery service and the nearest certified tech was in Massachusetts (I'm in Raleigh). Three weeks later, yesterday I picked it up and didn't think much about the range meter being at about 65 (thinking was just poor customer relations to not give me a car at full charge, but no big deal).

Got home and have been unable to charge above 74 miles. UGH. Tried my L-2 charger, the 120V VW charger, immediate charging, and programmed (midnight) charging - same result. I'm hoping it's simply a matter of resetting something or a Battery Management System software update. Any ideas??

From the service ticket, they "Removed and replaced j996, j1002, j1045, and j1046, performed module addressing test and rechecked for faults while attached to vas 671001 no faults. Performed insulation test passed. Cleaned lower housing replaced upper battery housing and performed leak test passed. Reinstalled HV battery and recommissioned HV system. Road tested 5 miles and charged battery."

At 100% SoC, GOM reads 74 miles?

Which battery module was found to be faulty? Was that module changed? What do all the J codes mean? I think you need to get the dealer to tell you in more detail exactly what they did.

 

[jackconn]

Yes, it won't charge above 74 miles. My interpretation of the service ticket is that the jxxx listed in the description from the dealer are the 4 battery modules that were changed. On the bill of material, there are four "CELL MOD": two are 5QE915599AJ, one is 5QE915599AK, and one is 5QE915599AH. I'm assuming the different p/n's are from variations in the casing to fit in various places in the battery pack, but that's just a guess.

 

[f1geek]

Yes, it won't charge above 74 miles. My interpretation of the service ticket is that the jxxx listed in the description from the dealer are the 4 battery modules that were changed. On the bill of material, there are four "CELL MOD": two are 5QE915599AJ, one is 5QE915599AK, and one is 5QE915599AH. I'm assuming the different p/n's are from variations in the casing to fit in various places in the battery pack, but that's just a guess.

I find it surprising that 4 modules were bad, so maybe talking to someone to confirm might be worth your while? Otherwise we are guessing, as you say.

It would be nice to see cell voltages - if you want to understand better what is going on with the pack - to do this, you need an OBDII dongle and software, like CarScanner. For sure you need to bring it back to dealer so it can fix its botched job.

 

[f1geek]

Yes, it won't charge above 74 miles. My interpretation of the service ticket is that the jxxx listed in the description from the dealer are the 4 battery modules that were changed. On the bill of material, there are four "CELL MOD": two are 5QE915599AJ, one is 5QE915599AK, and one is 5QE915599AH. I'm assuming the different p/n's are from variations in the casing to fit in various places in the battery pack, but that's just a guess.

I suppose it may be possible the BMS needs calibration and there is nothing wrong with your car, so maybe I shouldn’t assume a botched job. Have you charged car to 100% and then taken it for a long drive to observe GOM behavior and actually test usable range?

 

[jackconn]

That's exactly my current theory. Another data point is that we drove it about 20 miles last night and the GOM only dropped 8. I'm well aware of all the variables that go into the GOM number (at least I think I am) and I'm wondering if the work they did replacing the modules has scrambled something - temporarily or needing some form of reset. I'm wondering if we'll be able to drive it a lot more than the 66 miles it's currently showing. It does seem a bit odd that the current full-charge reading is about the same as what it was when I first brought it in. I've got a call into the local dealer and waiting for a reply...

Thanks for the input, I appreciate the discussion!

 

[f1geek]

No problem. Just to reiterate, if you can view all module voltages with an OBD scanner, you would probably be able to discern if there is a module with super low voltage, and that would be a real problem.

 

[jackconn]

To close this out....it took another few weeks and several visits by the regional corporate VW tech expert and the local tech to figure it out. Turned out it needed a "certificate battery test and battery adaption [sic] drive cycle. drove vehicle down to zero range and recharged twice. after two drive cycles range is now reading 141 miles and passed battery test." Don't know why the folks at Colonial VW in Westborough MA didn't do that after they finished replacing the 4 battery modules and before sending it back to Raleigh. I've been through two recharge cycles and it appears to be back to normal. VW had the car for about 9 weeks....

 

[f1geek]

To close this out....it took another few weeks and several visits by the regional corporate VW tech expert and the local tech to figure it out. Turned out it needed a "certificate battery test and battery adaption [sic] drive cycle. drove vehicle down to zero range and recharged twice. after two drive cycles range is now reading 141 miles and passed battery test." Don't know why the folks at Colonial VW in Westborough MA didn't do that after they finished replacing the 4 battery modules and before sending it back to Raleigh. I've been through two recharge cycles and it appears to be back to normal. VW had the car for about 9 weeks....

Great to hear. Thanks for final update. Good to know the BMS needs a few cycles to be calibrated after a module replacement.