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View Full Version : Shift Solenoid Code - What do you think?



DennisG01
12-23-2004, 05:30
I have gotten (2) codes that are identified as "Shift solenoid" - one is "A CKT" and the other is "B CKT". I lost the paper I wrote the numbers on, but I believe they are PO753 and PO758 (or something close to that). If I need to, I'll go back to Autozone and get them read again.
I have absolutely no drivability problems when the idiot light comes on. Do you think this could be an electrical connection problem, or something wrong with whatever the "Shift Solenoid" is. If it's electrical, where should I look to clean connections - am I right in assuming that the general are is on the left side of the transmission? Again, no drivability problems, just want to make sure this is not going to lead to something else.

ucdavis
12-23-2004, 18:03
480E tranny has two electronic shift solenoids that control shifting. Very occasionally folks report the tranny going into limp mode where it is stuck in 2nd. This is ordinarily fixed by rebooting the tranny (shut down & restart, just like Microsoft).
If it is only an idiot light intermittent, I'd monitor it & wait for good spring weather to open any connections.
Left side should be where you'll find the wiring harness & connectors.

DennisG01
12-26-2004, 19:02
Thanks, ucdavis. How hard is it to explain to me what exactly I should be looking at? I'm sure I'll probably clean any connections I see there, but it would be nice to know what is what. Anyone happen to have a picture?

Govt issue
12-30-2004, 12:30
youve either got a lose connection on the LT green wire and the yellow and black wires, or bad sol. You almost can't have a bad conection on the pink power wire because it didn't set a tcc code. The p0758 will stick you in second gear if the code is current. Both will command full line psi. Im betting on a conection problem where the harness goes into the trans.

DennisG01
01-01-2005, 09:47
OK, how about this scenario? I heard this possible explanation from a dealer: Since the only time when these codes show up are after a no-start incident (the dealer said I have a bad ignition module - and I do have to wait 10 minutes for the ignition module to reset until the truck will start), he says the "drop in voltage from the bad ignition module can cause the shift solenoids to set a code". And I have NEVER had any drivability problems when CES light is on.

Does this sound plausible?

I will still check connections on the solenoids. Is dielectric grease the way to go when putting the connections back on (after removing and cleaning)? What makes dielectric better than other types of grease? (probably a stupid question, but was just wondering).

Govt issue
01-03-2005, 07:54
That is not possible. because the computer sets the code after these conditions have been met.
p0753 system voltage is 10-16 volts
Ignition is on
engine runs at 475rpm for more than 5 secs and is not in fuel cut off mode.
pcm commands solenoid on and voltage remains high battery voltage
pcm commands sol. off and voltage remains low zero volts
all conditions met for 5 sec.
at this time the code is set. light on
p0758 is almost the same but the engine runs for 7 sec.