Main Battery trouble after period of disuse

Disconnect the 12V battery for a few minutes, then reconnect. That will clear DTC logged by most ECUs (except the SRS and skid control ECUs).

 

I have question for master Patrick Wong, if he is so willing... I have a friend with an '06 that was dead on the road, ostensibly because of HV battery. Was towed to her house. I came to look at it. Will not go into diagnostic/ready mode. 12V battery is fine. All lights work and so on but when I try to get diagnostic or ready, I get nothing! Unplugged the 12V battery for a few minutes, still nothing. Advise PLEASE! How to get to source of issue?

 

how many miles on her?

best to tag patrick, reply to his post, or pm him.

 

If you press the power button while your foot is on the brake, does the dashboard turn on or stay dead? MFD dead?

 

If the Prius will go into IG-ON mode, where the warning lights on the dashboard are on, then you should be able to retrieve the logged DTC. However, since you disconnected the 12V battery, most DTC will have been erased (except DTC logged by the skid control or SRS ECUs.)

What means are you using to retrieve the fault codes?

 

Here's something I found from testing for parasitic drain on the 12v system. Every so often if I didn't drive the car the 12 would be dead, maybe 3 days. Well I had a 1.5 amp drain on the dome fuse, doors closed, all lights off . If I put the dome switch in off position, drain's gone. Back in auto , drain was back with no lights on. Only thing the looked a miss was one bottom door light bulb didn't work. I popped the cover off, and it wasn't plugged in. I plugged it back in, and it worked. Guess what, no more drain in auto position. Dead battery solved. Guess the system knew a bulb was unplugged, and stayed in some kind of testing mode when car was off?

 

Don't know how many miles on it.... can't get dash to light up. I am using TSI. IT will NOT go into diagnostic OR ready mode, so tech stream is useless. MFD does not work. Thank YOU for your consideration!

 

OK, lets focus on the combination meter and the MFD. They receives 12V power from the following fuses: 10A GAUGE, 15A DOME, 15A ECU-B, 7.5A ECU-IG, 7.5A ACC.

Check the fuses by removing each one by one, measuring continuity across the fuse, then replacing it.

 

Papa......If this "death of the car" occurred while driving, your symptoms are exactly what happens when the AM2 fuse blows. When the AM2 fuse blows, it is usually due to the inverter cooling water pump failing.

See this thread for photos and more information...

Total Shut Down- No Warning Lights, Please Help! | PriusChat