ALDL Baud Rates / Pins

[TommyM]

I just swapped a '91 (16147060) engine harness and PCM into my '90 (1228747) Suburban, along with a 4L80E trans. I did NOT swap the dash harness, just the engine harness that runs through the firewall and plugs into the PCM. There's a white 5x2 plug that I had to re-pin. It basically had all the right wires in all the wrong places.

The swap is finished and it seems to be running well, but there's one little detail I'm needing to straighten out yet.

If I'm understanding correctly, the 7747 ECM only sends a 160 baud signal to pin E of the ALDL.

The 7060 PCM on the other hand sends a 8192 baud signal to pin M of the ALDL.

Is it correct that this is one or the other, either 160 or 8192 baud, depending on which ECM?

My diagrams for the '91 7060 don't show any wire to the E pin. If that's the case, I just need to pull the orange wire out of the ALDL E location, and put it in M, so that a scan tool can read it correctly, right?

Thanks,

Tommy

 

[4X4HIGH]

I'm fairly certain that the 7747 IS only 160 baud and i'm about 99% certain you cannot run a 4L80E trans with the 7747 ECM.

 

[TommyM]

I just swapped a '91 (I think 7060?) engine harness and PCM into my '90 (8747) Suburban. . .

Right. I took the 8747 out and am now running the one from the '91, which is a 7060.

 

[bigblock72]

Pin C11 on the PCM should go to pin M on the ALDL for serial data. There is not a wire in pin E on the ALDL.