I am looking to buy a 2002 Sport Edition SR5 2wd with 100,000 miles on it and when I drove it, I noticed that the VSC TRAC, TRAC OFF, and the Check engine lights are all on. This the second day I have gone and driven this vehicle (the first day was just a test drive, the second day I drove to the mechanic so he could look at it). Today, I noticed that the lights have not gone off as I have heard that when the lights go on and then off, it could just be a fuse or something. Anyway, I took it to the mechanic with the current owner and the owner said that he got both the Toyota dealership and the local Autozone to run a diagnostic test on it and they both said that it was the front O2 sensor.

The mechanic said that it was the ABS and the traction control (and something else that I forgot) and that it was a very serious problem that needed to be fixed pronto. I just want to know what you guys think it might be because if I buy this particular truck, this could be the difference b/w a $200 repair and $2000 repair. , Sam

It could be a $20 ABS sensor or it could be something alot more, you never know, just find another truck and dont worry about this one.

Have another dealer get the proper code from the computer. When I had a similar issue a few months ago, I was told it was my catalytic converter. Turned out, it was both of my O2 sensors. Replaced them in my 2002 Sport 4Runner and CEL went away. $170. Good luck.

x2 for me. had same issue about 6,000 miles ago on my Runner which has 148K miles on the odometer. stealership said i needed new catalytic converters. searched on this forum and asked around. replaced both O2 sensors. problem solved.

It very well may be the o2 sensor. Mine did the same thing and when I read the code it said it was the o2 sensor, I changed it and cleared the code and no problems since.

You'll have to get the code from the on board diagnostics (OBD2) to be sure.

Your mechanic should know this!!! Thats odd!!!

The vsc and trac operations are very dependent on the various sensors functioning properly and if there is an error on one they shut off vsc and trac off and turn on the cel.

I have this issue, instead of replacing the O2 sensor I've fixed the issue with electrical tape over the check engine and trac lights on my dash. Works great, maybe $0.01 "fix."

Just to be clear, what is the CEL? Thanks you guys by the way. I might see if the owner will let me take it to the stealership with him today or tomorrow and get diagnosed, again. I'll let you know what happens.

CEL= check engine light

Mine seem to all come on when I don't drive the 4Runner often (I ride a motorbike almost every day). I'll notice that all three lights (sometimes including the MAINT light as well) come on and stay on unless I drive to work and back (40 miles). The first time it happened, the battery was almost flat, so I attribute it to low voltage. Driving for a half-hour or more in traffic seems to recharge the battery sufficiently and the lights go off, usually in the same day. This is just my experience, but may apply to those who don't put lots of regular miles on their 4Runner. Your mileage may vary.

I also had the same issue a couple months ago, and it was fixed by replacing my O2 sensors.

CEL causes the other lights to come on. I had this issue a few weeks ago and it was a random cylinder 4 misfire. Cleared the codes at the dealership (scangauge wouldn't read them) and hasn't been back since.

Others say loose gas cap, cats are bad, need O2 sensor, etc. Bottom line, there are hundreds of reasons a CEL comes on. Unless you can see the codes from the dealer and know exactly what's going on, pass.

Is this 02 sensor you talk about the same as a transmission range sensor? These same lights have been coming on my 2014 4runner. They go off periodically and will come back on. I went to Autozone today and they gave me an Error Code of P0705 Transmission Range Sensor Circuit and said the most likely solution is to replace this sensor. Can this be done myself or do I need to go to a garage? Thank you.

try the 5th gen section
First issue with my truck, any ideas what's wrong?

I had this problem for years and it seemed that putting a bottle of red line engine cleaner in it caused them to go off along with the cooler temperatures of winter each year. I finally bit the bullet and replaced the O2 sensor. Problem solved!

The mechanic said that when an O2 sensor is on the verge of going out something as little as the temperature change can affect its performance