My 2006 HiHy 4WD-i with 26K miles had its traction battery fail this past Saturday.

The symptoms were that the ICE continued to run at all times, the regen braking no longer worked, the battery SOC indicator was moving up and down at a faster than normal pace, and the following warning lights were on:

- master warning
- check engine
- traction control (the skidding car)
- brake (the circle with exclamation point)

Also, the alpha display said to "check VSC system" and "check hybrid system".

On Saturday, my local dealer's mechanic retrieved the following DTC:

P0A80: Replace Hybrid Battery Pack (this is issued when the voltage difference between pairs of battery modules exceeds the standard)
C1259: HV System Regenerative Malfunction
C1310: Malfunction in HV System

He diagnosed that the traction battery had failed. Toyota tech support confirmed this diagnosis, and the new battery has arrived at the dealership. Hopefully the new battery will be installed tomorrow.

In the meantime, I have been driving a 2007 Camry LE 4-cyl loaner. Smooth and quiet ride, but by no means overpowered.

I haven't noticed other posts regarding HiHy traction battery replacement, so I thought group members might be interested to know what symptoms might point to a failed traction battery.

Patrick Wong