8.1 engine, 4L80e transmission. 233k miles. It started throwing multiple solenoid error codes and would not shift out of 1st/2nd gear. Cleaned the grounds under drivers door. Transmission shifted ok, codes went away and then started up again after a couple hundred miles. Found the connector on the side of the transmission leaking trans fluid. Trans shop thought that the leak in the connector was the cause of the error codes. Replaced the internal harness and the three solenoids. Still throwing codes. replaced the TCM. Still throwing solenoid error codes. All connectors have been cleaned with contact cleaner and di-electric grease applied. Any body have any ideas?
2005 Yukon XL2500 throwing solenoid error codes
- Thread starter josephc
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Maybe @NickTransmissions has a comment or two.
Yes, you still have a short somewhere in the system and/or one or more of your new solenoids or harness is DOA.
Harness brand should be Delphi or Rostra. EPC should be either Borg Warner or Rostra. Shift solenoids, pressure switch manifold, speed sensors, pwm solenoid should all be either AC Delco, GM-packaged or Rostra.
Keep looking - you'll find it...
DELCO PARTS. ( damn spellcheck )
External harness connector and 12 inches of harness replaced. Still not clearing codes. Any other ideas would be greatly appreciated. Cleaned grounds under drivers door. I am now stumped as to the next course of action. TYI
Check the rest of the external harness and connections w/the TCM and/or ECM, make sure there's voltage and continuity there. Also test the new transmission electrical components, if you haven't already...While it's very rare to see reputable name brands send out DOA parts, it does happen from time to time and all it takes is one bad part to throw it into limp mode. Also check/test the battery, alternator, cables going to and from the battery...Also check the ignition switch, associated grounds and so forth..This one sounds like it's buried somewhere and where ever it is, it's able to mess w/the transmission's electrical components...Sorry, I don't have any other ideas beyond that.
By chance do you have remote start? I ask this as my 05 silverado 1500 would not shift into 2nd. The installer did not do a good job and the fuse fuse inside the remote harness box was blown. Went back to Best Buy and the trainer for our area showed me the issue. I believe harbor freight sells a electrical tester for voltage and ohm drop testing.
Yes, we are down to the nitty gritty on this one. Battery and alternator check good, redid all the grounds in the engine compartment and under the drivers door on the frame. Doing a point by point check on the harness today. UGHHH! My nagging concern is that the dealer pulled the transmission twice to replace the rear-main-seal five years ago. Just a nagging feeling that the harness may be pinched above the tranny where I can't see or reach.
No aftermarket stuff on this truck. Its exactly the same as when I drove it off the lot.
Similar threads
