Questions re: CEL code reading with paperclip

[mudgudgeon]

So, my 80 had the CEL showing recently.

I have a TOYOBD1 code reader, but it's rarely works. So I tried to read the codes using a paperclip.

Jumped TE1 & E1, turned on the ignition.
CEL blinked, but no codes, just a steady blink until the key was turned off.
After removing the paperclip, and turning ignition back on, the CEL is gone.

What's the deal here?
Did the ECU decide the codes aren't relevant anymore?
Does jumping TE1-E1 to read codes typically clear them afterward?

 

[ppc]

More info required ... but if you didn't mess with the the TOYOBD1 after getting the CEL while driving then ...

Was the CEL light on before jumping the pins in the connector?
If not, then I would not expect that there were any codes stored in the ECM.
There are two types of codes that will turn the light on. Those that are "real time" faults will see a condition light the light and not store a code, as you drive if the fault corrects itself the light goes out. The second type will store codes in the ECM and may take one or two " trip logic " to set along with speed limits/ranges.

If you have a non-OEM battery setup (dual battery/solar controllers) or some other problem with the power source to the ECM that will erase stored codes as well.

 

[Brindleboxer]

@mudgudgeon

Question: Was the CEL still on when you parked the 80 to do the test? If not, the system cleared the code.

The codes on the 93/94 will clear once the system see a condition within the set parameters. Reading the codes using the paperclip method does not clear the codes.

The only way I know to reset the codes without fixing the issue is to remove the EFI fuse or disconnect the battery.

Lastly, you say the light is steadily blinking, does it blink once and then a slight pause then blink again? If so, I believe that is showing good condition and no codes present.

 

[jonheld]

Lastly, you say the light is steadily blinking, does it blink once and then a slight pause then blink again? If so, I believe that is showing good condition and no codes present.

 

[mudgudgeon]

View attachment 4236462

It was doing this.

CEL has been on everytime I've driven it recently, which is maybe a few short drives over the past 6 months or so. It is plugged in to a trickle charger all the time so battery level shouldn't be a factor

It seems to be running just fine. I drove it 4-5 miles with the CEL on, then when home I plugged in the Toyobd reader which doesn't connect to the app (or visa versa)
I think i gave up on it, and tried the paperclip but just got the steady blink