Engine Code Reading Error?

[El Bastardo]

Hello all,

I have a 1981 El Camino (231 V6) that has recently thrown an engine code. This is my first issue in the 18 months I've owned it.
I hadn't made any modifications to the engine, nor had I driven it hard. I can't explain the behaviour.

While driving around a few miles from my house the check engine light would blink five times, pause, another five times, and then a long pause. I brought it home and used the paperclip trick to display the code. I have a 5 pin port so I jumped the D and E pins (the one with the notch) and turned the ignition to accessory mode.

What happened next was a bunch of nonsensical blinking I couldn't nail down. I was already filming because I wanted to catch everything that was going to come up on the check engine light.

Does anyone have an idea on whats going on?
I think its probably looking weird because I have LED bulbs in there instead of the traditional bulbs so the resistance isn't what the ECM is tuned to for code reporting. I haven't swapped back because I haven't had the time.
Anyone else have any other ideas?

 

[Clone TIE Pilot]

Are you sure you are jumping the port correctly? 1981 is the oddball year where you ground the port differently from the later years. https://www.elcaminocentral.com/threads/gm-ccc-trouble-codes.27196/

The LED bulb may be an issue too.

 

[78Delta88]

I'm not seeing 12. It should flash 3 times, then the problem codes should show 12 for 3 times.

I think replace less with the proper incandescent bulb

 

[El Bastardo]

I replaced the 194 bulb in the Check Engine slot and I couldn't interpret what I was watching because the code was still rapid firing. I then replaced all of the bulbs with incandescent 194s and tried again.

This is what I got. Still can't figure it out. Thoughts?

 

[78Delta88]

I see the 12 but after that, it's not right. Can you send a pic of the ADL connector and how you have it jumped?

Even the 12 it's flashing isn't correct.

 

[El Bastardo]

I see the 12 but after that, it's not right. Can you send a pic of the ADL connector and how you have it jumped?

Even the 12 it's flashing isn't correct.

Maybe I'm jumping the wrong pins, or using the wrong material (paperclip).

I've got the paperclip slotted in the edge between the plastic and the pin instead of both pins.

Could be a fault in my technique

 

[stew86MCSS396]

Sorry can't help with the erroneous flashing...well with the EFI stuff I play with, rapid flashing normally means there's an issue with reading the PROM. Perhaps unseat and reseat.

As far as the connector, if there was a question of whether you're on the correct pins, D and E doesn't have a divider and you should be able to jump it with a small screwdriver or even a spade connector.

I miss my '81 Monte it was the second g-body in the stable. Young dumb and broke...swapped the V6 for a SBC. Needless to say it was short lived as the frost plugs started leaking from rusting out. Never put any effort trying to get it back on the road. 😥

 

[78Delta88]

Sorry for the delay, was with a client...

Try moving the jumper to the other end, I think you are in the wrong spot.

Reason for this is there was a 10 pin and 12 pin connector. There was another setup it was like 5 or 7 but not like yours. I think the other row is behind the plastic that at moment you can't see. See attached pics....

Move your jumpers to the other end. See pic below, or move jumper to the far right end bottom row, see pic below. It could be you are grounding the high speed data port which is causing the fast flashing, not sure...

For 1981, 1200 baud was "fast" modem connection, and I think you might have plugged into the 8000+ port which was super fast for 1981 data link.





Auto zone still has reader available. For 30ish dollars.

 

[Ribbedroof]

81 is a 5 pin unique to 1981 (and maybe 1980 with ECM, there were a few California combinations that had it)

Never had any luck reading mine, it would come on, but would not flash any codes when jumpered per the OE shop manual. Eventually did an ECM delete with regular HEI and 79 carb

 

[78Delta88]

81 is a 5 pin unique to 1981 (and maybe 1980 with ECM, there were a few California combinations that had it)

Never had any luck reading mine, it would come on, but would not flash any codes when jumpered per the OE shop manual. Eventually did an ECM delete with regular HEI and 79 carb

Was it just a 5 pin one row? I've seen others but they were a stacked style.