P3030

This is an excellent write up:
Toyota Prius code P3030 “High Voltage Line Snapped” - Luscious Garage | Hybrid Specialists

 

As i read this, it can be the sense wires that are broken/corroded, not just the bus bars.

"At this point you know there is a broken or corroded circuit in the harness, creating an open. The sensing circuits are very small 22 gauge wires connected to thin flat tabs that mount at the bus bars, which are easily fractured." - LG

Not everyone responds back with what solved their problem, but I have never seen an ECU be the problem, although many have been replaced.

 

Do you have techstream or any phone app that lets you look at block voltages? This problem should easily show up and point you in the direction of which block(s) are reading an unusual voltage.

If not, you really need to get it. It makes life a lot easier when working with the HV batteries.

 

What does the freeze frame data show for the P3030? It's showing all voltages as normal?

 

This is another good reason to buy a brand new sensor harness from Toyota. The man hours and effort involved in re-using an old harness is crazy compared to just purchasing a new one.

 

Those voltages are normal for when you measure modules individually with a meter. But that's not the problem. They are not normal voltages when being monitored by the ecu.

Techstream should have freeze frame data for a p3030 that shows all 14 block voltages (as measured via the sensor harness) at the time of the fault. If your modules are all exactly 7.95v then each block would in theory show 15.90v on techstream. The freezeframe data for the p3030 should show one or more blocks with a whacked number (assuming the snapshot caught the transient).

Something is happening between where a tab is attached to the terminal and the ecu. Either a voltage is off due to wiring issues or as you mentioned, the ecu is acting weird. The vast majority of the time, it is due to corrosion affecting the sensor tabs, micro cracks in the crimp area, or the plug not making good contact at the ecu.

 

Are you sure you have the orange safety plug locked? Push the plug in flip up the lever and then push that lever straight down till it clicks.

Did you balance the whole pack with a product like Prolong? That's really important and extremely beneficial. Takes at least 30 hours. Battery really likes that.

Did you load test each module? That's imperative one module going flat faster then normal then the rest is identified by the ecu and it will throw a alarm.

lastly look at the white plug that goes to the ecu look at it carefully make sure there is no corrosion on the plug or receptacle. Corrosion on the sense wires are sneaky it runs all the way up the wire under the wire coating so you never know how rotten it is.

 

Yes...............I believe we've had reports of this previously. At least one bolt needs to be installed and torqued.