My 87 4runner is running great but after its been on the highway for a couple of minutes, the check engine light will come on. It will go away if you coast or throw it into neutral for a second. On a prior post, the consensus was it was an O2 sensor. I replaced it, and sure enough the CEL is doing the same thing. Any help is more than welcome.

 

by the way, i cant find a shop that can pull the codes (i only checked one...and autozone)

 

You can pull the codes yourself.

Supplies needed:

paper clip
pad of paper
pen


Open the hood, find the "diagnostics" box, open it up. Using the paper clip short the Te1 and e1 connectors.

Get back into the truck, turn the key to the "on" position. Count the blinks of the CEL.

Come back here and decode them.

 

Pulled the codes: 5 blinks, pause, 11 blinks... any ideas anybody?

 

oops, reset the diagnostics, now it only blinks 11 times

 

drove it on the highway again, blinks 5, pause, then 11...again. Getting angry

 

I did a search for you and came up with this website:
http://www.troublecodes.net/Toyota/

It's been posted before, so the info is out there. Try searching for "trouble codes" or "11 blinks" or something - be creative. Someone has experienced your problem and the info is out there (broken record). The best way to find info is search. By the way, does your rig only have 1 O2 sensor? Many vehicles have 2 or 3, but I'm not familiar with 1st/2nd gen. Sometimes even after you get the code you have to guess - the same thing a shop will do, but it costs you less to do yourself. It sucks, but we're all out of warranty.

They should call the CEL the "learn patience light" or "learn to have a car repair budget light."

Good luck!

 

5 is O2 which there should be 2 of. 11 and is switch signal not quite sure about this but i found a thread about code 51, which is probably what you have, and found this.

SWITCH SIGNALS
IDL (tps) CONTACTS OFF, NEUTRAL START SWITCH OFF, A/C SWITCH "ON" SIGNAL TO ECU
WITH DIAGNOSTIC CHECK CONNECTOR SHORTED
--A/C SWITCH/CIRCUIT
--A/C AMPLIFIER
--TPS/CIRCUIT
--NEUTRAL START SWITCH/CIRCUIT
--ECU

the thread is located here:
https://www.yotatech.com/forums/f116...1-22re-136101/

My advice would be to get a multimeter and start testing all your sensors according to the specs in the manual. also dont forget to test the wires. thay can get brittle over the years or ground out keeping the signal from reaching the computer. thats what I told him to do also. Good luck

 

They should call the CEL the 'quick run to the forum, and post a pointless thread because im too lazy to pull the damn code, and would rather have people randomly guess whats wrong over the internet light'

 

is my thread pointless? anyways... so there are two 02 sensors...once again doooooped by the pep boys parts counter. thanks for the help. I think code 5 is gonna be the real head ache.

"chill out, You are being very un-dude" -Big Lebowski reference

 

i meant code 11 is gonna be the headache...

 

I thought 87s only have one 02 sensor? Anyways, is Bosch the OEM? And what are the chances the one I got from the store is defective?

 

You should only have ONE pre-cat o2 sensor UNLESS you have a california model truck. Duel o2 sensors came on all trucks starting in 95.5 (new taco and 4runner)

Do NOT buy bosch for your toyota. They just don't get along. Denso is original equipment IIRC But NGK (or ntk) is also one of the best.
Both are available cheap at www.sparkplugs.com

 

Its not specifically you, its more of a general thing. look through the thread list at how many people post threads about having a CEL, but never bother to check the code.

Thats correct the CA emissions models have 2 o2's, the federal emissions trucks have just the one.

If you do a search a ton of people have had issues with Bosch 02 sensors. Supposedly it doesn't stick deep enough into the exhaust. NGK & Denso are the way to go as they are OEM parts, and have worked well for a number of members on here.

 

denso ordered...fingers crossed. Everything else is running great (just got had a head job done, with a/c converted to 134a). If the light goes away with the new 02 sensor, if the code 11 does not trigger the light, but is still stored am i running any risks?

 

pull the efi fuse for a few mins while you install the new sensor, and it'll reset the computer and clear the stored codes. if you get any codes after that you'll know they're happening right then, and aren't stored

 

Well, I disconnected the negative battery lead, installed my freshly delivered denso 02 sensor. Hit the highway only for the light to come on, it was a little different from the Bosch (it would go off with putting it in neutral...sometimes). Pretty disheartening... pulled the codes: 5 blinks, 2 mississippi, 11 blinks..just perfect! Is there anyway this could be the result of a mis-step in a head job? Well, at least my title for this post is making sense again. Ideas anybody?

 

I repeat what I said earlier ohm out the sensors(all of them) and check wires for continuity to computer.

 

Just found the old multimeter... this should be scarey/educational. When you say ohm out all the sensors that includes: 02, TPS, airflowsensor (?) and...?

 

oh, by the way... when I removed the old 02 sensor, the connector going to the sensor had some exposed/torn copper (probably the source of the original problem). I replaced the connector with a new end. I know length of wire effects resistance...but this was like an inch...am i gonna need to replace the wire if the readings come back bad?