rickpaw

Hi guys,

As title says, can the plug be installed backwards, as in 180* off? I'm about wrapping up a 5.3l/4l60e swap into my 67 Firebird, and I'm getting the codes below, and start to think the trans does not get 12V power. I checked the fuse for trans and it's good. Have 12V power at the panel. Ran the car in gear on jackstands, and the trans never shifted. VSS works, as it was showing speed on my Torque app. Fluid level is good. I dropped the pan and replaced the filter. Trans is never been removed from the engine, and it's a dropout from a 01 Silverado.

P0758 shift solenoid b electrical
P0740 tcc solenoid circuit/ open
P0753 shift solenoid A electrical

I did not install the plug when the engine/trans were out of the car, and had to feel my way between the tunnel and trans to put in the plug. It snapped in tight so I thought it went in correctly. ECU/harness is from PSI reworked to be standalone. With the codes being electrical connected, I'm starting to think I have the plug in backwards.

Thanks.

mrvedit

I don't think it can be put in backwards as there is a plastic key tab in the connector. The connector has a big arrow on it which positions on the outside of the trans. The remove the connector, you need to squeeze it on the sides (including the arrow) and lift up.

You might need to drop the pan and check for +12V on the solenoids.

I don't think it matters, but what year is the PCM?

rickpaw

I don't know the exact year, but it uses red/blue connectors. Ecu came from psi conversion. What are the chances all the solenoids are bad at the same time. That's why I'm thinking the connector is in backwards.

mrvedit

There have been several similar threads in the past year. In most cases it was either a fuse that was bad (but looked good), a melted wiring harness (touched headers), corrosion on the connector or a not-fully-inserted connector. In those cases there was no +12V on the solenoids when the OP finally checked it. Minuscule chance both shift solenoids are bad.

rickpaw

Yeah, I did a search and most of it related to blown fuses or fried harness. I checked the circuit at the fuse panel, including the fuse with an ohm meter and they checked out. There is a guy on pt.com that had the same codes as mine, and it turn out the people who did the harness had every thing 180* off. I'm hoping that's the issue in my case.

rickpaw

Well, I compared the new harness with the old factory harness and they matched. I checked for voltage at the pink wire and it got 12v. So power is getting to the plug. Looks like I have to drop the pan.

mrvedit

Dropping the pan can get sloppy.
I typically use a hand fluid pump ($8 at HarborFreight) and pump a gallon out of the dipstick tube. Then either install a pan with drain plug or drill in an aftermarket drain plug.

It will be interesting to hear what you find (or don't find).

rickpaw

mrvedit, thanks for the replies. I'm kind of embarrassed to say that I put the connector in 180* off. I heard it click but it wasn't fully seated. Last night I found a test procedure to test the solenoids, and used the old harness pigtails to test it. It checked out. ran the car on jackstands this am and it shifted, no codes. That was a simple fix. Operator error.

mrvedit

Glad to hear you figured it out and it all works now.