P1776 - fyi
#1
09-21-2015, 02:51 AM
P1776 - fyi
Excuse the lengthy write-up, but I want to be thorough since there seems to be little concise information available for the subject of this post.
Our '99 Stratus with the 2.5 liter decided to light up the CEL and throw the P1776 code today. Happened as I was accelerating to get on the freeway and it wouldn't make the 3-4 shift then set the CEL. After exiting the freeway, it dropped into full limp-mode. I massaged it to a local AutoZone to get the code read. (Only afterward did I find that a full Key Off and Start cycle will usually pull the transmission out of limp-mode and resume normal shifting.)
Digging around online with Google searches yielded the meaning of the P1776 DTC - "Solenoid Switch Valve Latched in L/R Position" - but there is slim and sometimes contradicting information on what needs to be done to effect a repair. Some say that replacing the solenoid pack has fixed the problem. Others report that it requires a rebuild or replacement of the valve body in the transmission to fix it. And there are some reports that it requires replacing both the solenoid pack and the valve body to fix the problem.
I had noticed previously that the solenoid/transmission seemed to make an excessive amount of noise when putting it into gear, particularly the "solenoid buzz" that the older 41TE's are reputed for. But there was also a lag when going from Neutral into Drive with a lot of solenoid buzz while it tried to engage. Seeing that the vehicle is new to us and I was planning on doing a filter and fluid change anyway, I went ahead and did that procedure. The pan was relatively clean with what I would describe as as "as-expected" amount of aluminum "milk" lining the pan and a slight coating of material on the magnet. The fluid was red-brown and did not smell burnt. The filter was in decent condition. I carefully cleaned everything up, put the new filter and gasket on and torqued the pan bolts to 165 inch-pounds and added just a pinch over four quarts of ATF+4 to bring it up to level. I took it out for a test drive and all seemed okay until I recreated the same condition of trying to accelerate to freeway speed and it repeated the problem, wouldn't make the 3-4 upshift and the CEL came on. Another code reading confirmed the same P1776 error.
After weighing the options, I decided to go ahead and change the solenoid pack. Having done the same procedure on our '01 Town & Country, I knew what to expect and had the tools lined up, including the 1" socket for pulling the Input Speed Sensor. On removing the solenoid pack, the first thing that I noticed was that there were items rattling inside the solenoid - not just one, but several. I compared this to the new unit and the one that came out of the T&C, neither of which had any rattles. Encouraged, I was faced with the next dilemma: the spacer plate. I recalled reading a few posts that indicated that Chrysler did away with the need for the spacer plate when they re-designed the solenoid pack somewhere around the 2000 model-year. And the new solenoid did not have the mounting holes on it for attaching the sound shield that the old unit had. I decided not to reinstall the spacer or sound shield.
Once the new solenoid pack was installed, I started the car and checked the operation with the new unit. The buzzing is greatly diminished and the engagement into all gears is much quicker and direct. An extended test drive with several attempts to recreate the circumstance that set the P1776 code were in vain. The only issues remaining to sort out are some rather (at times) harsh 3-2 and 2-1 downshifts; upshifts are fine. I believe that this may require a "quick-learn" for the transmission, so I will be contacting local transmission shops to see what they charge for the procedure.
I hope this helps someone in the future when faced with trying to determine a course of action when faced with this problem.
Our '99 Stratus with the 2.5 liter decided to light up the CEL and throw the P1776 code today. Happened as I was accelerating to get on the freeway and it wouldn't make the 3-4 shift then set the CEL. After exiting the freeway, it dropped into full limp-mode. I massaged it to a local AutoZone to get the code read. (Only afterward did I find that a full Key Off and Start cycle will usually pull the transmission out of limp-mode and resume normal shifting.)
Digging around online with Google searches yielded the meaning of the P1776 DTC - "Solenoid Switch Valve Latched in L/R Position" - but there is slim and sometimes contradicting information on what needs to be done to effect a repair. Some say that replacing the solenoid pack has fixed the problem. Others report that it requires a rebuild or replacement of the valve body in the transmission to fix it. And there are some reports that it requires replacing both the solenoid pack and the valve body to fix the problem.
I had noticed previously that the solenoid/transmission seemed to make an excessive amount of noise when putting it into gear, particularly the "solenoid buzz" that the older 41TE's are reputed for. But there was also a lag when going from Neutral into Drive with a lot of solenoid buzz while it tried to engage. Seeing that the vehicle is new to us and I was planning on doing a filter and fluid change anyway, I went ahead and did that procedure. The pan was relatively clean with what I would describe as as "as-expected" amount of aluminum "milk" lining the pan and a slight coating of material on the magnet. The fluid was red-brown and did not smell burnt. The filter was in decent condition. I carefully cleaned everything up, put the new filter and gasket on and torqued the pan bolts to 165 inch-pounds and added just a pinch over four quarts of ATF+4 to bring it up to level. I took it out for a test drive and all seemed okay until I recreated the same condition of trying to accelerate to freeway speed and it repeated the problem, wouldn't make the 3-4 upshift and the CEL came on. Another code reading confirmed the same P1776 error.
After weighing the options, I decided to go ahead and change the solenoid pack. Having done the same procedure on our '01 Town & Country, I knew what to expect and had the tools lined up, including the 1" socket for pulling the Input Speed Sensor. On removing the solenoid pack, the first thing that I noticed was that there were items rattling inside the solenoid - not just one, but several. I compared this to the new unit and the one that came out of the T&C, neither of which had any rattles. Encouraged, I was faced with the next dilemma: the spacer plate. I recalled reading a few posts that indicated that Chrysler did away with the need for the spacer plate when they re-designed the solenoid pack somewhere around the 2000 model-year. And the new solenoid did not have the mounting holes on it for attaching the sound shield that the old unit had. I decided not to reinstall the spacer or sound shield.
Once the new solenoid pack was installed, I started the car and checked the operation with the new unit. The buzzing is greatly diminished and the engagement into all gears is much quicker and direct. An extended test drive with several attempts to recreate the circumstance that set the P1776 code were in vain. The only issues remaining to sort out are some rather (at times) harsh 3-2 and 2-1 downshifts; upshifts are fine. I believe that this may require a "quick-learn" for the transmission, so I will be contacting local transmission shops to see what they charge for the procedure.
I hope this helps someone in the future when faced with trying to determine a course of action when faced with this problem.
#2
09-23-2015, 03:33 AM
First follow-up:
Took the car to a local transmission shop to have the quick-learn done. The tech was using a Sun scanner than I didn't get the model of to access the PCM/TCM. After running out on a test drive, he informed me that there was no signal registering from the Input Speed Sensor, that he couldn't do a quick-learn on it with that problem, and that could be at least part of the problem with the harsh down-shifting. I'm going to be checking the wiring from the ISS to the TCM for continuity and have a new sensor ready if the wiring checks out. Will post updates as they come.
Took the car to a local transmission shop to have the quick-learn done. The tech was using a Sun scanner than I didn't get the model of to access the PCM/TCM. After running out on a test drive, he informed me that there was no signal registering from the Input Speed Sensor, that he couldn't do a quick-learn on it with that problem, and that could be at least part of the problem with the harsh down-shifting. I'm going to be checking the wiring from the ISS to the TCM for continuity and have a new sensor ready if the wiring checks out. Will post updates as they come.
