Scan tool port

[impendingdoom229]

Where is it? I have a '93 SR-5 and my check engine light comes on intermittently. I have a scan tool but I can't find the port, does anyone know where it is? I looked under the dash and couldn't find anything.

[Tech1984]

OBDII started in '96. All you have is a data link connector under the hood. (rectangular)
Use a paper clip or small jumper wire and connect TE1 and E1.
Switch the key on and count the blinks the CEL pulses. Might go like blink blink...pause...blink blink blink blink (code 24) then pause or start up again with multipul codes. Write them down.
Clear it out by pulling the EFI fuse under the hood for 30secs.

[impendingdoom229]

Thanks a lot for you help. I just did as you said and got code 54 and no others. Do you know what this cod means or where I could find out?

[Tech1984]

I have you down for a 1993 SR5 4cyl Truck, correct? If so, I do not have a listing for code 54.
You may want to double check the code again.

[impendingdoom229]

My mistake, it was code 52, and it's a 6 cylinder, but otherwise that is correct.

[Tech1984]

That is your knock sensor.

Book says:
With engine speed between 1,600 rpm −
5,200 rpm, signal from knock sensor is not input to ECU
for 6 revolution. (KNK)

Bottom line is you most likely have a bad knock sensor.
The pig tail wire harness that connects to it is also bad.
Unfortunately, this is all under your intake in the valley.
Not easy to get at.

Good luck.

[impendingdoom229]

How necessary is it to replace the knock sensor and do you have any guess as to how much it would cost?

[sam333]

Originally Posted by impendingdoom229

How necessary is it to replace the knock sensor and do you have any guess as to how much it would cost?

When the computer sees no signal / proper signal ( backround noise) from the knock sensor , it goes into failsafe mode and retards your timing to the max value, causing poor performance and gas milage.

Normally when your engine is knocking the ECM will retard your timing to prevent engine damage, but you will not get a trouble light. The light comes on when the ECM is not getting ANY or normal backround signal.

Like Tech 1984 said, its usually the pigtail on the 3.0 V6 and it is alot of work to get to. If you have a shop do it, it will be expensive.

Some people have had luck installing a new sensor onto the engine lift hook and bypassing the old one.
This has worked for some ,but you loose the protection of your knock sensor, since it is not in the proper place to detect knocking anymore.