2009 Red master warning , VSC and yellow brake system lights on. Only get intermittent acceleration.

My Prius automatic 2009, odo about 175,000 kms has recently suffered from the following and I’d really appreciate some tips on most likely causes from you dudes and dudettes….

• Red master warning light on all the time
• After driving beyond about 20kms, VSC and yellow brake system light come on and then I only get intermittent power when accelerating.
• Also have the following trouble codes but can’t access further sub-codes with setup I have….

ABS/VSC/TRC C1310 HV SYSTEM MALFUNCTION current but no history??
HV BATTERY POA84 HYBRID BATTERY PACK cooling fan 1, control circuit low current and history
HYBRID CONTROL P3000 BATTERY CONTROL SYSTEM current and history
I’ve searched the forum a lot but found nothing quite the same.
Any ideas??

 

Thanks dolj!! Just found a video on how to do that so i'll give it a crack. cheers

 

Hey there Dolj
I took the fan out and it had a fair bit of dust gunk in it so it was good to clean that out. when i put it back and cleared the trouble codes, it drove really well with no warning lights for about 20kms but then the same lights returned....bugger!!

Any other ideas?

 

Not sure it could be the 12v battery according to AUTOCODES....POA084, the Possible causes as
Faulty Battery Cooling Blower Assembly
Battery Cooling Blower Assembly harness is open or shorted
Battery Cooling Blower Assembly circuit poor electrical connection
Faculty Integration relay
Faculty Battery smart unit
Faculty Power management control ECU

so I think i'll check on these first.
By the way, I confirmed yesterday that the fan is blowing so it is strange.
I wonder if one of the HV battery cells was getting old and heated up too much, perhaps the fan could not keep the temp down low enough or would that trigger a different trouble code/light?

Thanks for the tips and doco TMR-JWAP but i confirmed the fan is blowing yesterday. Might check the connector for the fan as dirt could cause the signal voltage level to drop and run the fan lower than intended. I'll also check the other things noted in the reply i just posted above. I'll also run through the checks in the doc you posted where they make sense, given that the fan is actually running. by the way, for safety, what do you have to do before taking the hv battery covers off? Also, where did you get the repair manual pdf you posted up? very handy to have these!

 

SOLVED!!!
Finally, got it!!
In the end, it was one wire of a harness, as per the image of the page from the 2006 Prius Repair Manual.
The brown wire from the Battery ECU Connector, FCTL1, B11-10 to the Battery Blower relay No. 1 (B14-2) allows the Battery ECU to close the contacts on the relay and hence allow power to flow to the Battery Blower, so clearly, if this wire is not communicating (ie. it had open circuit, infinite resistance), then you'll get the P0A84 Trouble Code. The thing that threw me earlier was that I had thought that I had felt air flowing out of the exhaust duct from the HV batteries near the aux battery (there is a hole in the duct there presumably to cool the aux battery).
Note that previously I thought I had solved the issue a couple of times after 1. cleaning the HV Battery fan and 2. replacing the Blower Relay (as I had read that it had a closed contact resistance of 6kOhms).
Anyway, thanks heaps to everyone for helping me out and in particular, sharing the links to get the proper manuals - this is a GREAT forum for tinkerers like me without enough cash to pay to get this stuff done and I reckon this would have cost over $1k to get a mechanic to sus out and fix but I'm only guessing there. I used a Selidori link I found on this chat to get the manuals but can't post the link as the system says I don't have enough posts but you can search it on
It did cause one chrome pop-up to seemingly begin popping up continually (or maybe it was something else?) but well worth it to get the manuals which were and are vital to solve the problems assuming you have the mini-vci cable and Techstream software to get the trouble codes.
By the way, does anyone know how can I flag this post as SOLVED?

 

Thanks Bisco, very satisfying nut to crack as you'd well know!