stacks

im trying to retrieve the CEL codes on a 1993 es 300 for a friend of mine. when i perform the test procedure the CEL is just staying lit. the procedure i am using is Key off, jump Te1 and E1 terminals (i have done this under the dash aswell as under the hood) then turning the key to the run position. all accesories are off. i have tried it in park and neutral. jumper is making good contact. nothing is happening when i do this. is there something i am missing or some things to check?
the CEL is on constantly while driving and the car has died twice while driving.
any help is greatly appreciated. thanks

ES300NZ

you only need to jump the terminals in one location. But that will not be the cause of the fault / failure to display the codes. The car has OBD1, so your method is totally fine/appropriate.

What you explaining is an ECU fault, that is the only conclusion available. Disconnect the battery, leave it off over night (at least a few hours), and try everything again.

Then try another ecu if you can find one. You car does not have security built into the ecu so there is no concerns simply swapping out / in the correct ecu.

If you do get the ecu to function properly again, try inducing faults and reading codes to confirm it's working properly. I like to drop o2 sensors, cos the car will still start / run but will certainly drop a code for that .

Bear in mind, the car could have a fault with the light, (W) in older toyota (the code light), is an earth connection. The ECU completes earth for the light, so you apply IGN (run), power to the other side of the light, and find and splice the W pin on the ecu.