Toyota Corolla gone nuts


#1

Check engine abs wheel and brake lights have all come on. Speedometer will not function cruise control doesn’t work and my car won’t switch gears after the 3rd gear. At first I thought it was the speed sensor but I replaced the sensor and nothing. Anybody have any ideas?


#2

Help!


#3

@Sickest

The first thing you need to do is tell us what model year Corolla you have

Next, you need to see about getting all those fault codes read out

Did you recently have any work done . . . I’m kind of wondering if somebody blew a fuse, left something loose, etc.


#4

You also need to tell us under what conditions these symptoms are appearing. And whether all this stuff is happening at once and whether all the functions are returning either by themselves or after restarting the engine… or after some other action on your part.

Generally, if all the dash lights come on, the speedo dies, and the car loses power it means the engine has died. But without more details it’s kind of hard to tell.


#5

Absent the info requested above, my guess is the engine computer has put the car in limp mode. That happens if some input to the computer doesn’t make any sense at all, so the engine computer doesn’t know how to control the engine properly. An example might be if the air flow sensor became disconnected. Suggest not to panic, as it is quite possible this is a simple thing to fix. The first course of action is to have someone with the proper computer scan tool read out the diagnostic codes. If you like you can post what they read out here for more advice.


#6

mountainbike might be on to something

Perhaps all the warning lights are on because of some low voltage condition

Most modules will not work correctly, if the voltage is significantly too high or low

I could imagine a component/module going into limp home mode under such circumstances

It is also possible that there is a communications problem on the vehicle’s databus(es)


#7

It’s a 2011 Toyota Corolla and it’s all happening at once. I had some body work done to it replacing the front bumper, headlights, and fog lights. We took it to autozone and it came back as the speed sensor being unresponsive. After changing the speed sensor it’s having trouble switching to first gear it passes 4200 rpm before it changes


#8

I’ve checked all the fuses and none of them are out


#9

Why was the body work done, was it in a collision? (as TSM noted “or after some other action on your part” ) If it was, that adds a lot of complexity to this as many other things could have been damaged. You should take it back to the folks who did the body work and have them chase this down, they may have had to work with the wiring to change lights and not connected everything back in the original condition.


#10

The speed sensor is probably a transmission output. The transmission computer uses that measured value to determine when to upshift and downshift. Even though it was replaced as you report, I expect the speed sensor still isn’t working correctly. And an inoperative speed sensor could be responsible for limp mode operation. Suggest to focus the diagnosis on the speed sensor. If or until it’s been proven to be operating correctly, that’s the most likely culprit. Just a guess of course. I expect you already understand that a guess is about as good as you can get without your vehicle actually being shop tested.

Note that if you were in a significant-force collision just prior to this occurring, the transmission could be damaged also.


#11

Which speed sensor did you replace? The transmission speed sensor may be the culprit. Did you replace that one or the wheel speed sensors? Also, did you check the wiring to the speed sensor? I had the same condition on my Sienna and it was the wiring to the sensor that was bad, not the sensor. Other causes could include a bad alternator (Toyotas famously put on a dashboard Christmas light show for undervoltage) or a bad battery.