98 Hyundai Sonata no reverse no shifting

keith

Sr. Member
Joined
Dec 21, 2007
Messages
176
Likes
0
Points
16
#1
A car was brought to me and the trans was not working in reverse and was not shifting in forward. Only 1st gear as working. It is a 98 Hyundai Sonata GL 2.0L A/T He said it was working fine one day the next nothing. I stated checking into it and could not communicate with the TRans computer. I have a snap on solus scanner. So I printed of the wiring diagram and checked all the power wires and grounds to the computer and checked all the fuse everything was ok execpt a 12 memory wire to the transsmission computer (I think it is like a 12v memory to a radio) so I put power to the wire but it made no difference. (it is the white wire #16) Then I took out the computer and stated the car and it functioned the same way only 1st gear without a computer. So I got a computer on ebay and put it in same thing. And still no comunication with the computer. I have not check the wires between the DLC and the trans computer to see if they are bad, but that would only explain the communication problem not the trans problem. Any ideas would be helpful.

keith
 

keith

Sr. Member
Joined
Dec 21, 2007
Messages
176
Likes
0
Points
16
#2
I have been looking over the wiring diagrams. Does anyone know if a bad shift control solenoid in the valve body would cause this problem. I also check the transmission range swith and it seems to be working fine.

keith
 
Joined
Nov 14, 2006
Messages
2,079
Likes
0
Points
36
#3
You will have to get communcations with it.
Does pin 16 on diag connector have battery power?
Try a external power on scanner and see if it will go.
What transmission does it have in it?
Try a volt meter between pin 4 and 5 and see if you can get any codes.
 

Transman

Receptionist & Complaint Dept.
Joined
Nov 14, 2006
Messages
2,953
Likes
0
Points
0
Location
New Jersey
Website
www.edsofvineland.com
#4
Comm or no Comm, this trans has to go reverse & forward. At the very least the end clutch is burnt and toasty. Also, Don't be surprised if the computer you bought is smoked also. It is very common. Post back, Transman
 

keith

Sr. Member
Joined
Dec 21, 2007
Messages
176
Likes
0
Points
16
#5
Ok so I check all the wires between the DLC and the TCM and they were all good. I rechecked all the wires at the computer connector, all the power (both battery and ignition) are working. I also checked the grounds and they are good. I still get no communication, I tried my scanner on many other cars and other hyundai's and it worked. Is their any way it could be anything other that the Trans computer? In addition to this the trans functions the same with the TCM in the car and pluged in or I unpluged it and set it on the seat and the car functioned the same (no reverse only forward in 1st gear).

So your saying: the car should work in reverse the same as in forward with or without the computer working. Because that really changes things then I would need to get the trans fixed and the computer. But that does not make much since because I think it was working fine before (as far as I know). Thanks for the help.
 

Transman

Receptionist & Complaint Dept.
Joined
Nov 14, 2006
Messages
2,953
Likes
0
Points
0
Location
New Jersey
Website
www.edsofvineland.com
#6
Yes, I am saying this trans will operate without the computer in forward & reverse. It will not upshift and it will be at max pressure but it will go front & back. Have you checked ALL your fuses? I know there are fuses that don't seem to be in the circuit that can cause a no comm error. I will check to see if the inhibiter switch can cause a no comm error tomorrow, I think it can. Transman
 

keith

Sr. Member
Joined
Dec 21, 2007
Messages
176
Likes
0
Points
16
#7
Please let me know what an inhibiter switch is. Maybe where it is? and If I how I can test it if I can?
thanks keith
 

Transman

Receptionist & Complaint Dept.
Joined
Nov 14, 2006
Messages
2,953
Likes
0
Points
0
Location
New Jersey
Website
www.edsofvineland.com
#8
I'm sorry, the "Inhibiter Switch" is what most people call the "Neutral Switch" and on these newer vehicles all of the information between the PCM and the transmission goes through this bugger. It seems that all manufacturers call this item by a different name. GM calls it a "Range Mode Switch", Ford calls it a "MLPS" (Manual Lever Position Switch). I did not get the chance to follow up today though and definitely will tomorrow, in the meantime please check connections for corrosion (green fuzzy stuff) and at the battery also (too often overlooked). Transman
 

keith

Sr. Member
Joined
Dec 21, 2007
Messages
176
Likes
0
Points
16
#9
ok, thanks let me know if that range switch could stop communication. I will check keep looking into and let you know what I find. Thanks