Upon driving...very randomly and rarely the check engine light just flashes on for a split second and disappears. If something was wrong I'd assume that the light would just stay on for good right? It's happened maybe 3 times...when I'm driving and for a split second it comes on and off. It happens under normal acceleration.

 

That has happened to me as well 93TT. I was told that it could be a lose connection somewhere, ground or a sensor connection. Go over you grounds and look at as many sensors as possible.

 

93TTRX7 and NeedTwins: the check light comes on for a reason- the reason being that some engine component malfunctioned. about 6 months ago, i used to get check lights as well, for split seconds. turns out that my water thermosensor was starting to malfunction. it would work fine, and then all of a sudden for a split second it would send a completely out of wack voltage signal to the ecu.

this is what you guys need to do: take a paper clip (reshape it) and use it to short-circuit GRD (ground) and TEN in the diagnostic unit of your car. the diagnostic unit is under the hood on the drivers side close to the battery. its a small square black box and it should say diagnostic on the box. open it and use the paper clip to connect TEN with GRD (the box will have the map of the pins). then get inside the car and turn ignition to ON (don't start the car). once you have done that, if your ecu has errors it will display them to you via the check light. what your looking for is a flashing check light. small flashes will represent a single unit and long flashes will represent units in ten. for instance, if you see a big flash followed by two small flashes, then it means that its error number 12. if there are more than two errors in the memory it will flash the next one afterwards. once it has displayed all the errors, it will continue the cycle with the first one.

do some research on the internet about checking error codes. or PM me with the error code and i will tell you what the error code means.

so far i had three error codes (9 for thermosensor, and i think 15 and 19 for tps sensor).

good luck

 

Yeah, flashing light can indicate a failure in a sensor or the connection to it. Maybe it's just poor connection but usually it's a sensor somewhere. Read the code and find out. You can erase the code after reading it and then wait a week or two to see if it reappears. If so, you've definitely got a repair.

 

Great info, will do that today. Thanks

 

thanks for the info, will try it

 

My guess is EGR, or like redrotary said, a thermal sensor. These sensors don't send voltage, just resistance. The reason I think that it may be the EGR sensor is because of how the sensor is only on durning very specific moments. If there were a short (which is no shocker), then the chances of getting a flickered signal is higher. The EGR sensor is just two pieces of metal that touch when the sensor is at rest.

 

yah mine did the same exact thing, flash once then stoped...happened about 10 times...and then....








my TRANNY BLEW!!!

 

Does the check engine light come on if the battery is dead? I haven't been driving my car for a while, but I noticed that every time I jump it to start it up the check engine light is on. It was not lit up before I put my car into storage. I have tried unplugging the battery and the ecu and reconnecting them, but no luck. Anybody know what could be causing it?