Immobilizer

What were the codes when it was in this state?

Sounds like you had less problems with the original components. Have you tried changing back to the originals?

 

When you change the immobiliser, there is a pairing procedure you must do. I don't know what it is, but search the Gen 2 forums (using the Advanced Search function) to find the info.

 

If you got that info from the repair manual, it should link you to the appropriate procedures.

 

Any idea what the fix is? My sks key will start my car (with out being inserted) and unlock my doors, but my car alarm goes off for no reason. I have a B2799 now. Which ecu do I need to replace and how do I register it? I have to unplug my battery every night when I park the car. The alarm going off at 4am is annoying.

 

I'm not sure that you have to replace anything- yet. What did you do to get your car "working"?

Get a copy of the service manual and it has procedure listed in the "engine immobilizer" section for registering communication ID between the transponder key ecu and the hybrid control ecu. It also mentions that you shouldn't power the car on more than 20 times before registration or the key ecu might cease functioning.

I have no idea what is triggering the alarm though. The immobilizer shouldn't trigger that. IDK if the Prius or Techstream has the function where you can review the last several alarm trigger events. (I have seen that on some cars).


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I did not know I had a working sks key. I replaced the battery in the fob (silver emblem on back). The only one I thought worked was a black back that would only start the car when inserted. None of the buttons on the black back key would work though, because my car is an SKS 2005 Prius. So, with that black back key I had errors B2775 and B2795. Understandable now.

Only after I started using my sks key did the alarm start going off at 4am. Strange? The car would now unlock without using the sks fob buttons, lock with the black button on the exterior handles, and start the car without inserting the key. Also, all the fob buttons work on the sks key.

Until I figure out what is wrong, I unplug the 12v battery every night.

Now, the only error I get is the B2799. Once, I got error B2796. It looks like I need to check my transponder and hv control ECUs and the wire harness.

First, I'm going to try the SST jumper between dtc cg-4 and tc-13 with the IG on for 30 minutes to see if the ECUs just forgot each other. This car was parked for over a year with no 12v battery in it. A lot of people seem to have a problem with parking these cars for long periods of time

Also, something else is strange with this car. It has a pioneer navi stereo. I think something happened when it was installed. I bought the car this way. When the head/running lights are not on and you pull back on the blinker (temporary high beams) something beeps 3 times quickly. The high beams do not come on and the high beam indicator doesn't turn on. Also, the energy display sometimes switches to the consumption display.

 

Somebody has installed a stealth 'EV button' by the description of your symptoms. Pulling back on the indicator stalk should engage EV mode. The three beeps indicate EV mode cannot be engaged at this time. There should also be a message on the MDF to that effect.

 

Just so every one knows; after disconnecting the battery for two nights, I left it connected and the immobilizer error has not come back. I did not do the DTC jumper for 30 minutes. The ecus must now be communicating though because i don't have any errors. The B2799 error reoccurred after the first night I disconnected the battery. But after the second night, it hasn't come back. I was only disconnecting the battery because the alarm was going off at 4am.

 

I have used it a couple times since you told me what it is. That is definitely what it does. This is a 2005. It changes the screen from energy to consumption, but there is no indicator for EV mode on the screen that I have found. That switch no longer temporarily turns on the high beams. That's what I was expecting it to do.