Taco Help Needed --->

**MOHSHSIHd** · 08-21-2007, 10:36 AM

So my 02 taco has the check engine light on. Its been on for a while, and im 99% sure is the O2 sensor. Truck runs fine and has always been maintained, but its still driving me crazy with the fucking light on. The checker in town got their code reader stolen, and I know you can do it with a test light, but I can't find anything online that explains how to use a test light on a taco or what the codes mean. I'm leaving on a short road trip with lots of stream crossings and stuff and don't want to get stuck out somewhere if something is really wrong.

thanks

**AsheanMT** · 08-21-2007, 10:39 AM

Don't those things turn on at certain mileage intervals to prompt you to take it in for normal maintenance?

**lemon boy** · 08-21-2007, 10:43 AM

goto the napa.

**pechelman** · 08-21-2007, 10:44 AM

go down to the local autozone where they check it for free
write down the code and let us know what i means

look carefully under the hood for any loose vaccuum lines or anything like that. also check the fuel cap is nice and tight. then go ahead and reset the ECU to turn off the engine light by removing the 20A fuse (i think). It should be labled on the fuse box cover or something.

my gf's highlander had the light come on with an Emissions failure code of sorts (me thinking it was an o2 sensor issue also) and it turns out a vaccuum line was disconnected that went to her airbox. plugged it back in, reset the ecu, and whala, light went off for good.

**MOHSHSIHd** · 08-21-2007, 10:45 AM

well mine came on when I started it up one morning when it was like -10 degrees. Im assuming frozen condensation in the 02 sensor triggered the light. From what I have heard its very common for tacos to get the light turned on because of the O2 sensor.

**kneedropper** · 08-21-2007, 10:46 AM

The same thing happened to my 97. After the checker reading I ordered the sensors. If I can remember correctly, they both totaled about $90 delivered and the install took about an hour. It should take about 10 minutes, if you can find someone who's messed with them before. I think buying new sesors would be about the same price as taking it to a shop and having them check it out. My truck ran fine for 6 months before the light pushed me over the edge.

**kneedropper** · 08-21-2007, 10:49 AM

Oh, and there is also a sensor that can trip the light right behind the air filter box. You'll need to buy some electronic cleaner spray, but it would be prudent to clean that first to see if it makes the light turn off.

**Dug** · 08-21-2007, 11:04 AM

Originally Posted by kneedropper

Oh, and there is also a sensor that can trip the light right behind the air filter box. You'll need to buy some electronic cleaner spray, but it would be prudent to clean that first to see if it makes the light turn off.

Yeah, the MAF sensor. I'd probably give that a check first and clean it well with some MAF sensor spray or electronics cleaner spray. Dont use anything harsh like carbeurator degreaser though and make sure you don't touch the wires inside. Might as well clean your throttle body while you're at it.

Oh, and I personally reset the ECU and get rid of light by just unplugging the battery for 15 mins or so. Good chance to clean the contacts.

BLOOD SWEAT STEEL · 08-21-2007, 11:08 AM

Originally Posted by kneedropper

Oh, and there is also a sensor that can trip the light right behind the air filter box. You'll need to buy some electronic cleaner spray, but it would be prudent to clean that first to see if it makes the light turn off.

MAF sensor. Yes, it's the most common cause for Tacoma CEL's, especially those with 2 or 3RZ motors. It can also cause sluggish start up (sputtering) when cold for a few minutes, and heavier than normal carbon deposits from the tailpipe. Don't touch the little wires, just sprat them off and reinstall. Pull the EFI fuse for about 15 seconds, put it back in, and then go drive. If it starts throwing codes again, get it checked out.

Most likely it's not the O2 sensors. In my experience, they rarely go bad in Tacomas.

**MOHSHSIHd** · 08-21-2007, 11:15 AM

well, I did disconnect the battery for like 15 minutes last week. Light stayed off for one whole day of driving, then came back on.

Ill try cleaning the MAF and see what happens.

thanks

**lemon boy** · 08-21-2007, 12:00 PM

FYI - Cleaning things and changing out things at random without getting a scan done occasionally works but generally is a fool's errand.

**MOHSHSIHd** · 08-21-2007, 12:22 PM

anyone have a code reader?

NAPA doesn't do it, shithole Checker in town "lost" their code reader, and I don't want to pay if its something that I can easily fix.

**lemon boy** · 08-21-2007, 12:48 PM

Autozone?

**Damian Sanders** · 08-21-2007, 12:59 PM

#1. Read the Code. Go to Autozone or anywhere else in driving range that has an ODB 2 scanner. These are general devices and work on ANY modern car built in the last 10 years. It is a 4 digit number and there will also be some text involved. You can buy a code reader for about $100 if you can't locate one.

#2. Look up the code on www.yotatech.com forums. A search will be able to fully explain what is exactly going on.

#3. It's highly likely that it's the rear O2 sensor. You will probably see a code like "P0141 Rear O2 Heater". That means your rear O2 sensor is toast. You can buy one online for about $100, at most discount auto parts places for $135, or at the dealership for more than that. Adjust pricing for where you live, parts may be cheaper or more expensive. That sensor wears out every 60K miles, like clockwork.

#4. If it is the O2, replacing it is easy. There are two small bolts holding it to the exhaust, a gasket, and tha connector plug. You don't even have to jack the car up. Just get in there with some metric tools and deal with it.

Good luck.

**chaka** · 08-21-2007, 01:00 PM

damnit. I thought we were going to talk taco recipes again!

**daPig** · 08-21-2007, 02:11 PM

O2 sensor article:

http://www.4x4wire.com/toyota/4Runner/tech/O2_Sensor/

MAF article:

http://www.4x4wire.com/toyota/mainte...tenancep5.html

**MOHSHSIHd** · 08-23-2007, 03:14 PM

well, I cleaned out the MAF and the light stayed off for 500+ miles and about 25 of that being off-road.

Looks like the MAF was the only problem, otherwise it ran like a dream. Kinda can't believe im gonna sell it.

**Kski** · 08-23-2007, 04:47 PM

All the rear 02 Sensor does is tells the ECU how efficiently your Cat is working. If you pull a code for the rear 02 sensor you can ignore it. The front 02 sensor is the one that gives the ECU closed Loop Feedback.

**MOHSHSIHd** · 09-02-2007, 12:03 PM

ok, so the light came back on. finally got the code read.

P0128
Coolant Temp
Below Thermostat
Regulating Temp

WTF?

Found some shit on the taco forums about replacing the ECU?

im lost otherwise....

**Jax** · 09-03-2007, 10:28 AM

Thermostat. Maybe $30 to replace?

If you still throw a code after replacing the thermostat then you may need to replace ECM, although that is probably not likely.

P0128 is a generic code, not specific to Toyota. If it were your O2 sensors, it would read P1XX, cylinder misfire, bank X.

I have an OBDII code reader for future reference, if you keep having issues.

**smolakian** · 09-03-2007, 12:12 PM

yotatech.com is a pretty good forum for tips/troubleshooting

4x4wire.com also has some good tech/maintenance stuff

These are the 2 sites I go to first if I need to do something on my Taco.