I have a 2009 Camry Hybrid with about 16,000 miles on it.

About two weeks ago, one morning I had the Check Engine light (MIL) came on. I immediately checked the gas cap and found out it was loose - actuall it wasn't sitting right (mis-treaded). I closed it tight and checked the code with a handheld scan tool (Equus 3130 Innova). The code was P1423 which is Toyota-specific (Fuel Tank Gross Leak). Then I reset the code and drove about 110 miles. When I checked yesterday, three of the readiness monitors were set as "ready", only EVAP was still showing "not ready". At the end of the day yesterday, I came home and parked the car and during idling, all of a sudden, dashborad lightened up (X-mas tree), indicating:

Check VSC System (Vehicle Skid Control)
BRAKE light is on
Electronic Break light (circle showing break pads outside adn exclamation mark inside) is on
Skid control light is on
ABS light is on
Check Engine Light is off

This morning, I took the car to the dealer. As I write this, they are trying to figure out the problem.

I have no clue what might have caused this problem. In the discussion groups I have seen all kinds of answers and they seem to be incorrect for the most part. One claim is that the loose gas cap may cause a VSC code. How are they related is a mystery to me. Second claim is that hand-held scan tools can cause all kinds of MIL codes. It could be true for certain brands but I checked the Innova's web site to see if my scan tool might have caused this problem. They claim that it does not command, control or otherwise enter information to the vehicle. It only reads off the information. Therefore, it is impossible for the tool to damage vehicle's electronic system.

Whatever the cause, I will eventually post the outcome.

 

Low 12 volt battery.

 

Recently I've got the 15K services done. As part of this service, the dealer replaced the battery posts and cables and checked the battery condition. It was fine.

Today, after the entire day of diagnosis and calling Toyota, the dealership decided to replace my ECU. Since it will take sometime to receive the unit, I am on a loaner for the time being.

I will give another update once they replace the ECU.

 

Why would they do that?

 

You got back to your house, you had multiple warnings on the dashboard and you didn't read the codes with the scanner which you apparently already have? Wow, that would be the first thing I did. If the check engine light was off, as it should be, all the other warnings are somehow related to the break systems, including VSC and skid control.
Well, I do agree that faulty (either by design or some particular fault in particular unit) scan tool could fry a computer, I would think it is very unlikely and also should affect the car right away, not some time later and BTW, if the scan tool reset the error code I would call it entering info to the vehicle, but still not the likely reason. Open gas cap affecting VSC? I really don't think so. Either computer issue or some sensor fault. For example there is electrical boost for the breaks coming off 12 v battery, that could cause multiple warnings, but without the codes those "idiot lights" are pretty much useless. I would hazard the guess, that if the dealer changed ECU, they have no clue what's really wrong or the error codes made no sense and they just poking around, replacing most complex and most likely part to fail.

 

Most probably because they had "some" indication of a low 12 volt battery and that's ALWAYS the first thing to do, remove, clean and burnish the battery terminals and connectors.

 

FYI,

I got ther car back today from the dealer. They replaced the ECU and road tested (about 40 miles with my authorization). Everything seems to be fine so far. I will post another message after about 500 miles or so.

The reason they replaced the ECU was because the ECU did not communicate/calibrate. At the time of diagnosis the following DTCs were recorded:

C1203 (Engine control system communication circuit malfunction)
C1210 and C1336 (Zero point calibration of yaw rate sensor undone)
C1345 (Not learning linear valve offset abnormality)

 

I believe that there is a bug in the ECU which causes this failure. I have had an intermittent failure in my 2006 Toyota Highlander Hybrid 4WD-i with 54,000 miles of and on for the last 18 months. I just posted the complaint below to the NHTSA/ODI Safety Complaint system.

This input will show the commonality between Complaints #10139802, 10194711, 10251646, 10256617, 10259470, 10280157, & 10289084 which are for multiple Toyota/Lexus models. All these complaints say same thing in different words. Problem is a VSC alarm which sets off indicators for Skid, ABS, and other systems with the ECU computer causing an audible alarm and message to check VSC system. Alarm seems to partially disable braking system. Brakes become mushy and I believe front brakes are disabled. I know rear brakes still operate mechanically, and because ABS is disabled, rear brakes can lock up and skid if brake pedal is pushed hard enough. Standard response from Toyota/Lexus is to replace ECU computer. However, as you can see from above complaints, this does not always solve the problem.
My own complaint is for my 2006 Toyota Highlander Hybrid 4WD-i with approximately 54,000 miles. I experienced a one time VSC alarm over 1 year ago when the engine start battery was dying. Toyota dealer told me to replace battery and see if problem continued. I replaced battery and also had all four tires rotated. Immediately after I started experiencing more VSC alarms at a higher rate. This has occurred while driving on highway as well as at low speed. It has also occurred both with and without applying the brake. 2 different Toyota dealers have attempted to "adjust" system to stop alarms without success. I have gone as long as 4 months without an alarm and then for no reason (no skid event) alarm reoccurs. Solution both dealers have now given is to replace ECU. Due to finances, I can not afford new computer, so I had a Toyota mechanic with 25 years experience install two different used computers with neither one solving problem. After examining the internet and your complaint board I now realize that this problem occurs across Toyota's product line and that there is no clear solution. I believe Toyota is aware of the problem and is not acknowledging that they have an ECU computer problem.