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I suspect either:
1) your ECU has leaking capacitors, causing it to throw random codes, or
2) your wiring harness to the transmission is damaged. It common for the transmission valve body connector (on the passenger side of the transmission, above the transmission oil pan) to get damaged from exhaust heat and short out, or
3) your transmission ground wire is damaged or has high resistance. I believe the ground connection is behind the driver side headlight on the radiator support.
That's a great point. 1987 should have 2 digit codes. Is it possible to someone swapped in a 1992 or later ECU in your 1987 truck? That might explain the ecu's confusion.
Plus, these are E4OD codes, which wasn't released until 1989.
Do you have a 3 speed auto transmission or a 4 speed auto transmission?
Here's a screenshot of another thread, that explains how to check engine codes on an '87, since it doesn't have a "check engine" light either.
It might be worth it to go through this routine to verify what codes you're getting, just in case something is throwing your code reader off.
Another weird thing about this truck is the engine.
In 1987, the 4.9l wasn't offered as an option. So where did it come from? You need to look at your vin and door tag carefully and see what the truck came with from the factory.
Caveat to the 4.9l: any truck could be special order with the 4.9l, but they were usually destined to logging companies or forestry services for some reason.
Good evening yall. I just bought a OBD1 scanner and hooked it up on my 1987 F350 with 4.9L
I got 10 codes and here is the ones I got. Can anyone advise me on these?
116
542
552
621
622
624
626
629
637
654
First
A 1987 only outputs 2 digit codes
So, somebody switched processors for a newer truck? That means the rash of codes are irrelevant
I wouldn't worry too much about it, and I'd put a card over the check engine light (unless you need to pass I/M)
first thing to do is disconnect the battery for around 5-10 minutes to clear any stored codes.
after reconnecting battery, go for a ride then check codes again.
they may just be stored codes from a long time ago,
