Diagnosis, anyone....

I seem to have found a great shop...planning on spending another $250 for them to open up the battery and poke around. Good idea...or just change the battery and skip the inspection part....Also, how efficacious is it to just change cells? This is their assessment so far.

Hybrid System Inspection Result -​

- Am able to duplicate customer concern.
- Warning lights activate during periods of extended drive time or increased temperatures.
- DTC'S present- HV BATT- P3023: Battery block 13 becomes weak
- P0A80: Replace Hybrid Pack
- HV ECU- P3000: HV system malfunction
- P3009: HV Power Short Circuit
- When the warning lights set the vehicle will not accelerate over about 18 MPH.
- During this condition, while accelerating from a stop, the vehicle seems to shutter.
- The HV battery prefers to have a state of charge between about 20 and 80% but generally is around 45-60%.
- During this failure the state of charge was between 95 and 100% which is very, very high.
- During test drive, had noticed that as soon as P3009 is set and cleared, it returns immediately, indicating that there is a
short occurring at that moment.
- Inspected HV cables under the vehicle, all look good and intact.
- Inspected HV connections, they all look good at this time.
- Monitored battery block 13 before, during, and after failure.
- Voltage is a bit lower than the other battery blocks, approx 1.0v
- This does indicate that battery block 13 is possible failing, but not a definite failure.
- When the warning lights activate, P3009 is not set all the time but P3023 and P0A80 do set every time.
- Engine RPM increases and the HV cooling fan is activated on high speed.
- This is in attempt to cool the battery pack.
- It is possible that the 100% state of charge that is represented on the scan tool is false and just a misinterpretation of
actual data.
- If battery block 13 is failing and the resistance value is different from the remaining battery blocks this could cause
some confusion for the HV ECU.
- Will need to continue test drive the vehicle until the P3009 DTC duplicates to verify if there is a HV leak in the battery
pack.
- If so will need to remove the pack to verify concern and continue testing.
- The DTC's that continue to set definitely indicate a failing battery.
- Have test driven about 200 miles.
- The P3009 DTC has set only a few times and once it is set and cleared it does not return.
- Because the DTC does not return until another test drive, I am unable to verify where the voltage leak/short is in the
system.
- Every time the HV warning lights turn on both P3023 (Battery block 13 becomes weak) and P0A80 (Replace Hybrid Pack
are active) codes
- While monitoring data on scan tool, am able to see a greater fluctuation of voltage for module 13 of the HV battery pack.
- This indicates a failing module.
- During test drive also heard a loud pop sound from the rear of the vehicle, possibly from where the HV battery is.
- It is not uncommon for these batteries to blow the top off the module or begin to leak causing the P3023, P3009, and
P0A80.
- Will need to remove the HV pack to inspect and verify condition and state of charge of each module.​

- It is possible that the pack is in good working order but I will not be able to tell without further testing.