2009 Warning Lights Will Not Turn Off, Even when Faults Cleared

How is the 12v aux. battery?

 

It's very common for people who are using alternatives to Techstream to post about having "no codes" when they have warning lights on. It is much more peculiar to see that if you are using Techstream. However, it should be able to provide a wealth of other information even if for some reason it isn't showing you codes. What version is it, and what are you using for a dongle?

Can you post screenshots of the Data List screens for a few of the ECUs? Maybe the brakes, for starters, since you mentioned a brake warning light.

-Chap

 

Hmm, well, here's a thing sort of jumps out at me: that screenshot you've posted only even shows four of the car's computers: Engine & ECT, Hybrid Control, HV Battery, and Cruise Control.

There are at least twelve computers in your car: those four, plus steering, skid, gateway, transmission control, transponder key, meter, body, A/C, and Power Source. Thirteen if you also have smart key. These are the ones in the 2004 book ... by '09 there might be even more, depending on your option level. Hm, I almost left out the ones on the AVC-LAN: the MFD, and nav, if you have it.

There are at least eight, nine, ten computers in your car that Techstream is showing you absolutely no information for. It is not even saying it failed to contact them. It is acting like it has no clue they are even supposed to be there. This I have not seen before.

What version of Techstream is this? What are you using for a dongle? And what did you tell Techstream you were connecting to, in the start up connection dialog?

The codes for the warning lights that won't go out are being reported by one or more of those computers that are absent from your Techstream health check. This is what usually happens to people who are using generic, non-Techstream readers. (At least the generic ones have an excuse ... they honestly don't know any other computers are supposed to be there.)

Ehh, that gets said a lot here, but if "phantom codes" is ever going to mean more than "codes I assumed were meaningless because I didn't know what they meant and they didn't come back right away when I blindly cleared them", the evidence bar has to be a little higher. A code is genuinely bogus if: it gets retrieved, it gets looked up to understand what its detection condition is, and that detection condition was demonstrably not present when the code was set. That there would be a bogus code. Short of that, there are just codes folks choose not to follow up on.

-Chap

 

Brake codes can be read by the Tc-to-CG jumper, count-light-blinks method, takes the scan tool out of the loop.

-Chap

 

Correct; CAUSE-EFFECT.
The brake light is still lit b/c there is a problem. If the ECUs did not detect a problem, the brake light would NOT be lit. If you cleared all codes and the brake code came back immediately, then there is a problem somewhere. Maybe a creature chewed on the wheel sensor wire?

Techstream ver10 is more than adequate to read the 2009. I'm on ver8 for my 2007.

Lack of regular use will discharge the 12V battery, and is not good for the HV Battery.
Driving 5-10miles once/twice/three times a month will NOT recharge the 12V battery. The Gen2 Prius 12V bus only puts out about 4amps. Better to just make the care READY and lit it sit for hours (say 24).

Best to get a smart AGM compatible 12V battery charger. A non-AGM compatible charger does not recharge to a high enough voltage and will cut off prematurely b/c it things the connected battery is fully recharged, when it is not. Post #5&#8 have some useful information on testing the Prius 12V battery and smart AGM chargers; Is my inverter coolant pump slowly failing? | PriusChat

Why not just drive the Prius periodically? Twice a week to work? Once a week or every other week?

 

I'm doubtful of that figure. AHetaFan measured an order of magnitude more going into the aux battery when it was low on charge. That was a Gen 3, but did the DC/DC converter behavior change all that much Gen 2 to Gen 3?

The figure of 4 or 5 amp charging may come from the recommendation on the battery label. Maybe it is close to what the charging current really is if the battery is near full charge. But before Gen 4, the car doesn't really have a current sensor located at the battery, and really just regulates voltage. As AHetaFan's readings suggest, that can mean that at low states of charge, it significantly exceeds the current recommendation on the label.

-Chap

 

congrats! time for a cat?

 

Had a rats nest on the battery of my truck and daily dropping in my Prius, bought some plug in gizmos, 3 for 3$ that electronically, ultrasonically, repel rodents, four years ago, no rodent signs since, you have an infestation, the infestation-ERS have no reason to not intfestate.