U029A: Lost communication with hybrid Battery Pack Sensor Module

Yesterday I took my Prius 2012 for a car wash. When the work was done, I started the car but it gave me (for the first time) the check engine light. I got worried and I switched off the car at which point the engine rattled heavily just before it stopped.

I got a diagnostics guy to check the issue and the console gave the error: U029A: Lost communication with hybrid Battery Pack Sensor Module.
This got me worried and first thing I thought of was checking the battery pack. We managed to get it opened but everything looked intact, there was no sign of anything faulty. My mechanic advised to change the battery controller (which I believe has the sensor) but we couldn't get a replacement.
My hunch kept pointing to what could have happened at the car wash, water must have been spilt in a sensitive area. So I asked that we take a look at the wiring at the floor near the driver and co-driver seats. We got the plastic covering these areas off and as expected found water inside two connectors at the right side (driver's side in my country), We sprayed the water out and cleaned them dry and voila, everything worked perfect.