hi everybody,

i am from Türkiye. I bought a truck last week. he has some problems.

1986 sr5 efi 22rec,

-first i tried to check and find correct vacuum pipes. may be i did it

-i couldn t clear engine check light, code is 4
-temp gauge always goes up and down

here is some photos and videos.... how i fix it?

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The coolant gauge problem looks like it may be a failing Zener Diode in the gauge.

Edit: i just looked into the code 4; which is an open or shorted water temperature sensor. I would assume that your truck is like the later models, and has one sensor for the ECU, and one for the coolant gauge. If this is the case, your gauge problem has nothing to do with the code 4 caused by the ECU coolant sensor or its wiring.

 

I would first check the resistance of the sending unit. Either check it when your gauge reads normal and again when it drops, or leave the ohmmeter attached to the sending unit and watch it as the truck warms up. If you see any sudden changes in resistance, then it is your sending unit shorting out. Also check that all of the wiring connections are good with no corrosion, including on the gauge cluster circuit board. If these things are good, then it is most likely the gauge itself.

 

I have seen toyota gauge sensors do this before. Typically I find the sensor will pass all resistance checks in a bath of water, but you run a stream of water across it and the resistance changes or jumps all over the place. If you ground the wire from the sensor to the gauge should go to full heat and stay there, if it does that I would suspect the sensor. rustypigeon is correct though this is not the cause of your check engine light.

 

Thank you for your replies. Yes, Vehicle has 2 sensors, once is coolant sensor and the other for temp gauge. I can find the sensor for coolant gauge, but i couldn t find temp sensor for ECU in Türkiye and its part number. If i drive to go with this problems, engine will be damage or not? Do you know the parts number of these sensors? My vehicle is 85-86 sr5 one cab 2.4L 22RE-C and has 5 manuel trans.

 

The sensor for the ECU is on the front of the intake manifold. Here isa link with a picture...

http://personal.utulsa.edu/~nathan-b...36electron.pdf

Later model trucks used a green electrical connector for the ECU coolant sensor, not sure if yours uses the same.

 

Your part is SENSOR, WATER TEMPERATURE (FOR E.F.I.) 89422-12010

 

thank you for your reply, but i found from toyodiy

^^89422 SENSOR, WATER TEMPERATURE (FOR E.F.I.) 89422-30020 ^^

these 2 parts are same or not?

 

89422-30020 is discontinued superseded by 89422-12010

 

ohh that is super advice, thank you brianh699.

 

toyodiy has some old part #'s on it. If you go to http://www.trademotion.com/partlocat...?siteid=214001 and enter the old part # it will give you and updated one if it has been discontinued.

 

ok brianh699, i ll search the web site immedately. thank you again

 

Glad to help

 

Anybody know where I can get a circuit diagram for the temperature sensor?

 

https://www.yotatech.com/forums/f116...ge-fix-271152/