P0753 Shift Solenoid A

[ssdoeg2]

Howzit going guys,

Hope you guys can help me as I've spent the last 5 hours doing searches on here and club lexus regarding the p0753 error code and I haven't found an answer. I've been working on a 1995 LS that had a tranny issue. The tranny would not work at all when I first started on it so I did a complete tranny flush and it started running but with a pause and a harsh engagement whenever I went into drive from park or neutral (going into reverse is OK). I took it for a spin the other day and noticed that it now also seem to be slipping in drive. I drained pan (oil looked a little dirty again), cleaned the solenoids and it doesn't slip now but still has harsh engagement. Put a scanner on and got a code p0753. Sorry for the long story but what I need to know is what solenoid is the shift solenoid A that the error code states? I have a 1991 shop manual(appears to be same tranny in the 1995 except for shifter)and it lists the solenoids as 1,2,3 and 4. The troubleshooting matrix (page AT-156) also lists solenoid #4 as a possible problem for harsh engagement. Is solenoid #4 shift solenoid A? Any advice appreciated.

[curiousB]

Well if you were planning to take off the oil pan again you might want to measure the resistance of the solenoid coils. You should be able to do this from the cable harness too and save a messy step. Solenoids are pretty simple devices. A coil of wire on a bobbin around a moving iron plunger. Typical failure mode is open circuit (wire blows like a fuse link) and therefore resistance goes to infinity, or a short circuit (wires heat up, insulation melts and wire coil welds together to a short circuit) in this case resistance would be very low and possibly continuity to chassis.

You said you had a service manual so that should locate you for the cable harness plug and pin-out.

[ssdoeg2]

Thanks for the reply Curious B. Kicking myself for not doing the resistance checks yesterday. Took car for a spin this morning for a little more troubleshooting and here’s what I’ve got. After a few minutes of driving tranny will slip and at a standstill on an incline (my driveway entrance) car will slip in 2nd, 3rd or Drive and not move unless I give it some gas (> 1000 rpm) but in low gear car will move as soon as I give it any gas at all. If I turn off engine and restart it tranny will not slip initially but will start slipping after a few minutes of driving. This led me to believe that there may still be blockage in the valve body so that’s why I dropped pan again yesterday and cleaned the solenoids, filter screen and oil strainer but no change . If symptoms above clearly point to a bad solenoid someone give me a holler. Cleared code, took vehicle for a spin and was able to get code p0753 to repeat. The manual I’ve got is for a 1991 and diagrams are a little different on the 1995 from what I can see visually (fuse box in engine bay is different) so I guess I’m dropping the pan again to check the solenoid resistances. If the solenoid reads bad I’ll change it out and go from there. Got to go to work shortly but will dive into it in the morning. Going thru some type 4 fluid (6.95/qt on Maui-price to live in paradise!!) but still hoping I don’t need a new tranny yet. Thanks again for all replies.

[curiousB]

Maybe this helps:

I'd focus on solenoid A, Probably open circuit or shorted..... Might be easier to just pop a new one in and see if problem goes away... Or if you don't mind opening up tranny a few times. Swap A for another coil which has the same part number. I think some of them are common. Then you should see problem morph to a new error code and at least know you're in the right general area.

_________________________________________

P0750 Shift Solenoid A Malfunction

P0751 Shift Solenoid A Performance or Stuck Off

P0752 Shift Solenoid A Stuck On

P0753 Shift Solenoid A Electrical <<<<<<<<<<<<<<----------------------

P0754 Shift Solenoid A Intermittent

P0755 Shift Solenoid B Malfunction

P0756 Shift Solenoid B Performance or Stock Off

P0757 Shift Solenoid B Stuck On

P0758 Shift Solenoid B Electrical

P0759 Shift Solenoid B Intermittent

P0760 Shift Solenoid C Malfunction

P0761 Shift Solenoid C Performance or Stuck Off

P0762 Shift Solenoid C Stuck On

P0763 Shift Solenoid C Electrical

P0764 Shift Solenoid C Intermittent

P0765 Shift Solenoid D Malfunction

P0766 Shift Solenoid D Performance or Stuck Off

P0767 Shift Solenoid D Stuck On

P0768 Shift Solenoid D Electrical

P0769 Shift Solenoid D Intermittent

P0770 Shift Solenoid E Malfunction

P0771 Shift Solenoid E Performance or Stuck Off

P0772 Shift Solenoid E Stuck On

P0773 Shift Solenoid E Electrical

P0774 Shift Solenoid E Intermittent

P0780 Shift Malfunction

P0781 1-2 Shift Malfunction

P0782 2-3 Shift Malfunction

P0783 3-4 Shift Malfunction

P0784 4-5 Shift Malfunction

P0785 Shift/Timing Solenoid Malfunction

P0786 Shift/Timing Solenoid Range/Performance

P0787 Shift/Timing Solenoid Low

P0788 Shift/Timing Solenoid High

P0789 Shift/Timing Solenoid Intermittent

P0790 Normal/Performance Switch Circuit Malfunction

P0801 Reverse Inhibit Control Circuit Malfunction

P0803 1-4 Upshift (Skip Shift) Solenoid Control Circuit Malfunction

P0804 1-4 Upshift (Skip Shift) Lamp Control Circuit Malfunction

[ssdoeg2]

Thanks, I'll check out all the solenoids tomorrow and see what comes up. Like I said above, my 1991 manual lists the solenoids as 1, 2, 3 and 4 instead of A thru E so if anyone out there has a 1995 manual would you mind posting the correlation of solenoids if possible (EX.- is solenoid #1 the A solenoid?). If it helps any my 1991 manual shows solenoid #1 as the solenoid on rear of valve body near the pan drain bolt location (looking up from underneath)with #2 next to it. Then it shows #4 solenoid and then the #3 solenoid closest to the front of the car on the valve body. So it's listed as 1,2, 4 and 3 from back to front of car. Thanks for all replies.

[curiousB]

Here is location and naming of solenoids for my car (a 2004)... Might not be helpful for a 1995 though.

[curiousB]

maybe some help here:

...http://www.automaticchoice.com/Catalogue/aw_a650.pdf

...http://www.clublexus.com/forums/gs-second-generation/481169-p0750-shift-solenoid-a-malfunction.html

[ssdoeg2]

Thanks for the info Curious B!! I dropped the pan this morning and pulled off all 4 solenoids. All of the solenoids were in spec for the resistance readings and solenoids 1,2 and 4 checked out ok for the mechanical test (valve movement) but solenoid #3's valve would engage when voltage was put on it but not disengage completely when voltage was removed. I removed the hex bolt at the end of the solenoid, took out the spring and sprayed contact cleaner on it twice, cleaned it and verified there was free movement of valve before putting spring and bolt back on. I reinstalled the solenoids, closed it up, put oil back in, took it for a spin and she runs great!! There was probably some gunk and rubbish on valve causing it to stick and not function properly but when you turned the car off the valve slowly disengeged back and the tranny would seem to work again at startup until it(solenoid)engaged again and stick again. Stoked that tranny seems to be OK after a 10 mile run with no problems noted. I'll see in the next few days of driving if I'm out of the woods but it seems like I got the problem solved. Thanks Curious B and to all for all your help!!!!!!

[curiousB]

Awesome, got to love those repairs where no parts needed!!! As you say probably just some gunk impeding movement of solenoid.

[ssdoeg2]

Again, many many many thanks Curious B for your guidance and help!!

[rodl]

I have the same solenoid issue. Has your fix continued to prove OK? How's your car running?