Ice not starting

The B1271 indicates you have a failing combination meter (CM). I'm not sure that it has any connection to the other "lost comm" codes but it does need fixing.

For DIY, there is a good thread here (with links to another good thread). If you don't want to read it all, pick up the thread here towards the end of page #12. There is a good video on how to dismantle the dash on page 15 towards the end.

If you don't want to do the electronic repair, but feel competent to dismantle the dash, remove, and replace with a repaired CM that will be set to your milage and warrantied for life, then see Texas Hybrid Batteries (THB) - Rebuilt Combination Meter.

If you are in Texas and you're not wanting or able to DIY, then you can get the CM installed by THB for a reasonable cost.

If you are not in Texas and you're not wanting or able to DIY, then let us know where you are in the world and we can maybe give you a lead.

After fixing the CM, if you clear the codes and still have the U0123/4/6 codes you will need to work through the repair manual for how best to do that. For Toyota Service Information and Where To Find It, see here for more info.

 

I'm not sure but leaning towards no on the CM causing all these problems, definitely no on some of them. A definite no to the CM not allowing the engine to start.

Not necessarily. The only thing that could be grouped together are the U123/4/6 codes.

I was thinking that too. I don't believe there is any way that the OBDII could not use the CAN. That is why I'm advising that you clear the codes, after saving the diagnosis file. I'm interested to see if any of the U012x codes come back.

So, where are you at at this point?

 

I've never used the following link, but it should contain *everything* you need : Service Manuals - Google Drive

It would be great if you could extract the manuals from Gdrive and back them up on http://mega.nz/, then post the link here afterwards.

 

I really think you are barking up the wrong tree here. There are 11 - 13 ECUs in total. As you correctly said the OBDII uses the CAN to communicate via the gateway to some of them. If you can see any one of these ECUs:

• Body ECU
• Transponder Key ECU
• Combination Meter ECU
• Certification Key ECU
• A/C Amplifier ECU

(i. e. they show as white after a health check) then that proves the communication path from the CAN to the BEAN (body electronics area network) via the gateway is working. Further, if you have live data on the MFD, like the outside air temperature, instantaneous MPG, and can set and change A/C settings, it also proves the AVLAN via the gateway. in addition to all this, if the Gateway ECU was the problem, then there is a U0146 lost comms code for this.

Again I think you're clutching at straws here. Firstly, there is a code for a high voltage isolation fault - namely P0AA6. Secondly, even if there is an HV isolation leak, the design of the high and low voltage systems keeps them separate from each other.

So you mean every single code U0123, U0124, U0126, C2121, C2122, C2124, C2318, B1421, and B1271? I ask because in the first scan B1271 was showing in the history column. Out of all these codes, the U012x code would be the ones of interest. Most likely these are caused by a fault in wiring, which you would need to eliminate by testing the wiring loom before moving on to deciding that any ECU is faulty. While there are times an ECU gets damaged or fails, they are extremely reliable so generally, the fault is elsewhere.

The diagnostic chart for these codes is extensive and more than could be covered here, so you really need to avail yourself of the repair manual and then just roll up your sleeves and get on with diagnosing the problem. I'm picking a loose or faulty connector or a broken wire given that it seems to be (or was) intermittent. What is the rodent situation for where you live? They do like to chew on the Prius wiring.

PS, can you complete more of your profile to include your car details and a location for where you are?