1. Join the Community!

    DSMtuners is a massive archive of DSM information - but more importantly, it's a COMMUNITY! Join in and participate with other DSMers, and invite all of your DSM friends to make this place their home. Chat with others, create a build thread, post questions and answers. Get involved! Logging in will also remove many of the advertisements, along with this notice. ;)

1G Shift Solenoids Bad?? Replaced But Still Have TCU Codes...

Posted by autodsm, Aug 31, 2012

Please Support ExtremePSI
Please Support STM Tuned
  1. autodsm

    autodsm Proven Member

    108
    2
    Joined Jul 31, 2012
    wa, Washington
    Been chasing one big headache of a problem with this damn car. 1991 Laser FWD...original trans had toasted clutch packs and a broken band. Replaced with a different trans and have had nothing but headaches.

    Finally got it to "drive" but its in limp mode and stuck in 3rd gear. Pulled the TCU codes and got codes 41, 42, 83, 84 which all indicated SHIFT SOLENOIDS A / B OPEN / SHORT CIRCUITED.

    So I pulled the shift solenoids from my old trans and installed them...had the battery disconnected for a few hours. Start the car up and STILL IN LIMP MODE. Pull the codes and get the SAME EXACT CODES. 41, 42, 83, 84.

    Do the codes stay stored in the TCU even after you disconnect the battery for several hours? Or maybe my old solenoids are shot too....no frickin idea where to go from here...one thing after another and I am burnt out from this. Any way to test the solenoids or where should I go from here? Two sets of solenoids and the same exact codes being thrown each time....what gives!?
     
    Last edited: Sep 1, 2012
  2. knochgoon24

    knochgoon24 DSM Wiseman

    4,753
    65
    Joined Jan 29, 2008
    Troy, Michigan
    Look in the factory service manual. There are copies of it online. It shows you how to go through and test all the electronics for the transmission. I did it and found that I have at least one bad solenoid.

    All it takes is a multimeter and some time.
     

    2K  1

    1997 Mitsubishi Eclipse Spyder GST
    fwd · manual · 2G DSM

    1K  0

    1991 Eagle Talon N/T
    manual · 1G DSM

    2K  0

    1996 Mitsubishi Eclipse GST
    automatic · 2G DSM

    2K  0

    1997 Eagle Talon TSi AWD
    13.869 @ 95.090 · 2G DSM
    Loading...
  3. autodsm

    autodsm Proven Member

    108
    2
    Joined Jul 31, 2012
    wa, Washington
    It is just really odd to me that I change all 3 solenoids and get the same codes. I am fed up with this car....I will try and find the FSM
     
  4. knochgoon24

    knochgoon24 DSM Wiseman

    4,753
    65
    Joined Jan 29, 2008
    Troy, Michigan
    You may have some damaged wiring somewhere.
     

    2K  1

    1997 Mitsubishi Eclipse Spyder GST
    fwd · manual · 2G DSM

    1K  0

    1991 Eagle Talon N/T
    manual · 1G DSM

    2K  0

    1996 Mitsubishi Eclipse GST
    automatic · 2G DSM

    2K  0

    1997 Eagle Talon TSi AWD
    13.869 @ 95.090 · 2G DSM
    Loading...
  5. GDNF2ET

    GDNF2ET Proven Member

    534
    9
    Joined Feb 12, 2003
    VA Beach, Virginia
    Any chance you have the two, auto harness plugs switched ? Pulse generator and shift solenoid square plug..
     
  6. autodsm

    autodsm Proven Member

    108
    2
    Joined Jul 31, 2012
    wa, Washington
    I downloaded the FSM last night...it says for 1990 and mine is a 1991. Figured things couldnt be TOO much different...and while sifting through the pages, I came across where it talks about the solenoids but didnt see anything on testing them at all.

    Also GDNF2ET, I HAD the two plugs swapped when I first got the car back together...bryanwheat had suggested it and I swapped them just to see and then after that my car "started driving" but only had third gear. A that time I pulled codes and got 41, 42, 83, 84.

    I swapped the solenoids from my old trans and get the same exact codes! And i am fairly certain when I checked for codes before pulling my old tranny, I got constant short pulses, but i could be wrong.

    I have read somewhere about applying 12v and hearing the solenoid click or something, but not sure exactly what to do....or what to ohm the solenoids out at. Couldnt find it in the FSM. So if both sets of solenoids are bad, I just find it a bit odd. Any suggestions on testing them out?
     
  7. rts91tsi

    rts91tsi Proven Member

    191
    3
    Joined Feb 3, 2009
    Rockford, Michigan
    You can use MMCd TCU for troubleshooting 1g's to some extent. Just like MMCd's test for the ECU actuators, it has the ability to turn on the shift solenoids, as well as read and clear DTC's.

    It is available here in the files section. To use it you need to swap the pin from #1 to #6 on your data logging cable, and a Palm, or Palm Emulator for PC.
     
  8. autodsm

    autodsm Proven Member

    108
    2
    Joined Jul 31, 2012
    wa, Washington
    I went out and applied 12v to yellow and orange solenoid wires on the trans....the solenoids were clicking each time 12v was applied and released. Decided to test my solenoids that I pulled out and what do you know...they clicked like they should!

    So I ohmed out the wiring between the TCU and the plug for the solenoids and the wiring is fine with no breaks.

    Which led me to then test the TCU itself....i have two units and they tested EXACTLY the same. I got 5v from the middle prong on the green transistor. I put the car in drive and tested the voltage on the car side of the plug...got 2.4v and 1.9v for the solenoid wires. Went and put the gear selector into L and 2 and go the same exact voltage readings.

    1st gear from my undersanding is both solenoids open, which means I should have been reading 12v at each pin. 2nd gear is solenoid A closed and solenoid B open, so I should have read 12v off of at least one pin. No matter which gear I was in, L 2 D N R P, it still read 2.4v and 1.9v for each pin.

    So where do I go from here? I assume both TCU's are bad??
     
  9. GDNF2ET

    GDNF2ET Proven Member

    534
    9
    Joined Feb 12, 2003
    VA Beach, Virginia
    Are you sure the plugs are correct now ? If not I will visually check on my car for you what the colors are...

    This page is from a 94 factory manual...Let me know if you need more...
     

    Attached Files:

  10. autodsm

    autodsm Proven Member

    108
    2
    Joined Jul 31, 2012
    wa, Washington
    I am pretty positive my plugs are correct.

    The SOLENOID plug comes out of the tranny has 3 wires...orange, yellow and blue. I connects to a square plug under the air filter.

    The PULSE GENERATOR plug runs toward the firewall and has 4 wires.

    I had those switched a week ago and the car wouldnt go anywhere...it had reverse but when I put it into drive it didnt budge. When I swapped the connectors, it had drive but it only had 3rd gear...limp mode.

    Can having the two plug swapped out fry the TCU? Because both TCU's I have run in limp mode and give me the solenoid codes. And BOTH TCU's never produce 12v at the wiring harness no matter what my gear selector is in.
     
  11. GDNF2ET

    GDNF2ET Proven Member

    534
    9
    Joined Feb 12, 2003
    VA Beach, Virginia
    Did you check to see if the fuse under the dash blew ? AT/BOITE
     
  12. autodsm

    autodsm Proven Member

    108
    2
    Joined Jul 31, 2012
    wa, Washington
    Checked it, tested it, pulled it out and even replaced it. It wasnt blown to begin with.

    Solenoids A and B ohm at 25 ohms. Pressure Solenoid is 4 ohms. All of them click when I apply 12v.

    With the vehicle running, I get 2.4v at the solenoid plug on the wiring harness side (with it unplugged from the solenoids). Park, Reverse, Neutral, Drive, 2 and L all have the same result...I never see 12v to the solenoid wires.

    The wiring is good, I get continuity through all the wires when I test it. It is something with both of these TCU's. The green transistor next to the 47uf cap gets 4.98v on both of my TCU's.

    My original TCU had been repaired by someone previous to me owning the car...the cap is replaced and there is a solder trail fixing the eaten traces. The "new" TCU i have has the original caps and the 47uf cap I see is leaking...if I wiggle the cap, I can see the acid moving under it. Looks like there is something that is possibly burnt to the left of the cap....a tiny resistor or something, not sure. I will get a picture of it
     
  13. GDNF2ET

    GDNF2ET Proven Member

    534
    9
    Joined Feb 12, 2003
    VA Beach, Virginia


    The A B SOLENOID plug is orange, yellow, blue out of the trans / orange, yellow, blue into the harness

    From the PULSE GENERATORs is 4 green wires out / red, yellow, green, white into the harness

    Join this board and post your problem there....
    Register
     
  14. autodsm

    autodsm Proven Member

    108
    2
    Joined Jul 31, 2012
    wa, Washington
    Wait, so you are telling me that the pulse generator plug...the 4 green wires goes to the 4 wire plug right under the air filter......and the shift solenoid plug with 3 wires goes toward the back near the speedometer cable?

    Because THAT is how I had it originally hooked up and when I put it into drive, the car DID NOT MOVE IN DRIVE. It only had reverse. THEN when I swiched it, all of a sudden I had drive but it was in limp mode.

    On MY CAR, I have ORANGE YELLOW BLUE from the solenoids and there is a connector right under the air filter that is RED WHITE GREEN BLACK.


    Heres the deal....ORIGINALLY I had the pulse generator plugged into the square 4 wire plug under the air filter. And I had the solenoid plugged into the 3 wire connector that is toward the back near the speedometer cable. When I put my car into reverse it was fine, but when I put it into drive, it went nowhere...I would step on the gas and it would rev soooo slow and then stall. I thought it was the torque converter but another member here told me I had the plugs switched.

    SO I switched the plugs around and my car drove but I was in limp mode. So I got a new rebuilt torque converter and put it in...I left the plug configuration how it was and I was still in limp mode (which is right now).

    So on your suggestion, I swapped the two plugs BACK to how I ORIGINALLY had them and now I have all gears and and no limp mode.

    So on the word of the other member, I ultimately gave myself more gray hairs. But now as it sits, the car is running properly, shifting through all gears and downshifting properly, etc. Two plugs and a sh**t-ton of headaches.
     
  15. rts91tsi

    rts91tsi Proven Member

    191
    3
    Joined Feb 3, 2009
    Rockford, Michigan
    Why don't you ring the connectors out back to the TCU to make sure they are connected correctly if you are unsure and save yourself the headache (No disrespect to anyone who has given advice about the connectors in question).

    Take a paperclip or test lead if available, and jumper the applicable pins on the TCU side, then test for continuity under the hood.
     
  16. autodsm

    autodsm Proven Member

    108
    2
    Joined Jul 31, 2012
    wa, Washington
    Read my post above...in which I stated I already tested all plugs for continuity and there were no breaks in the wiring.

    It was swapped wiring that was the issue....so resolved now. Thanks to everyone for their help
     
  17. Ejsmith50

    Ejsmith50 Probationary Member

    2
    0
    Joined Apr 21, 2015
    Newburgh, Indiana
    Hello, I have a 1991 Laser LS stuck in limp mode. Have codes 45,47 & 85. No ecu codes. Have a bunch of hours researching this. Tcu is fairly new. Trans works fine on home made simulator switch. Has correct volts on each pin on inhibitor plug and ohmed inhibitor switch, also fairly new. Haven’t purchased transmission service manual, yet. May be next move
     
  18. GDNF2ET

    GDNF2ET Proven Member

    534
    9
    Joined Feb 12, 2003
    VA Beach, Virginia
    Scroll down for codes http://w4a33.com/doku.php?id=tcu
     
    Ejsmith50 likes this.
  19. Ejsmith50

    Ejsmith50 Probationary Member

    2
    0
    Joined Apr 21, 2015
    Newburgh, Indiana
    Thanks for the info & link. Had the four wire plugs switched, because the one for solenoids was too short to clip on holding bracket, so I didn’t think it went there. After checking voltage on both 4 pin connectors, I found that the pulse generator pins had 2 volts. Then it made since. Now kills engine when put in gear. Glad to have a different problem to chase. thanks
     

Share This Page

Support Vendors who Support the DSM Community
Archer Fabrication ECM Tuning ExtremePSI Feal Suspension Fuel Injector Clinic Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications OHM Racing RixRacing RockAuto SouthBay Fuel Injectors STM Tuned Track Decals Track Sculptures VR Speed Factory WheelWell.com