Trouble Code P0751

[Ken Huey]

1999 Cherokee Sport 4.0L, AW4 Automatic Transmission, Selec-Trac 4WD...Engine starts & runs normally but vehicle does not move (at all)...Only OBD II Trouble Code is P0751: "Shift Solenoid A CKT performance or Stuck Off"...I understand the AW4 transmission is electronically controlled by 3 solenoids located on the Valve Body...I understand that Solenoid #3 "Shift Solenoid" controls the Lock Up Torque Converter...I understand that each solenoid should test between 11 - 15 OHMS; if good...I understand the process necessary to change one or all the solenoids...The information I have not been able to locate is a way to test the solenoids electrically without going into the transmission...Please remember the 1999 Cherokee Sport does not have a "Stand Alone" TCU (Transmission Control Unit) - In 1999 the TCU was integrated into the PCM (Powertrain Control Module)...I have yet to locate diagrams for the 3 PCM Connectors; C-1 Black, C-2 White, C-3 Grey Connector, to determine how to test the solenoids with an OHM Meter in a similar manner as testing the pre-1999 TCU Connector at C14, C15, & C16...Would appreciate any information on locating the connector diagrams or on testing the solenoids without going into transmission...Also, would appreciate any information/suggestions to troubleshoot my XJ's symptoms & Trouble Code P0751...Anyone in XJ Land delt with these issues...Thanking all in advance...Troubleshoot & test 1st - Spend $$$ 2nd!

[oderdene]

attached a wiring diagram from 00 XJ,

there shown TCU no direct connection to PCM. Please check.

[4.3LXJ]

Ken, the public library is your friend here. I got the wiring diagrams for my 4L60E there. They have complete Motors Manuals in the reference section. Just copy the one you need for a few cents and call it good.

[Mudderoy]

Those black boxes that oderdene posted are actually pdf documents. Click them and if you have Adobe pdf reader installed you should be able to see the contents of the attachment.

[4.3LXJ]

Hey Od, where did you get those?

[Ken Huey]

Thanks for taking the time to answer my post...Library was my first stop...Also tried used book stores...This isn't my first rodeo but it is my first XJ...No manuals that cover 99 XJ...Don't know about an 00 XJ but the TCU is integrated into the PCM on a 99 as stated in my Post...Just don't know which pins on which connectors to check OHM values of the solenoids...That is why I was asking for 1999 connector diagrams or suggestions/information from anyone that has delt with this problem on their 99 XJ...Think the diagrams are for a 4.7 which did have a seperate Transmission Control Module.

[4.3LXJ]

I found my info in the motors manuals, not a specific manual for an XJ

[Ken Huey]

I found my info in the motors manuals, not a specific manual for an XJ
This is my first post & I tried to be as specific as possible concerning the problems with my 99 XJ and the type of information I was seeking to avoid generic replies...Appreciate your time.

[oderdene]

Hey Od, where did you get those?

once downloaded from www.greatlakesxj.com, now their web updated and most links were not working :(

[Ken Huey]

1999 Cherokee Sport 4.0L, AW4 Automatic Transmission, Selec-Trac 4WD...Engine starts & runs normally but vehicle does not move (at all)...Only OBD II Trouble Code is P0751: "Shift Solenoid A CKT performance or Stuck Off"...I understand the AW4 transmission is electronically controlled by 3 solenoids located on the Valve Body...I understand that Solenoid #3 "Shift Solenoid" controls the Lock Up Torque Converter...I understand that each solenoid should test between 11 - 15 OHMS; if good...I understand the process necessary to change one or all the solenoids...The information I have not been able to locate is a way to test the solenoids electrically without going into the transmission...Please remember the 1999 Cherokee Sport does not have a "Stand Alone" TCU (Transmission Control Unit) - In 1999 the TCU was integrated into the PCM (Powertrain Control Module)...I have yet to locate diagrams for the 3 PCM Connectors; C-1 Black, C-2 White, C-3 Grey Connector, to determine how to test the solenoids with an OHM Meter in a similar manner as testing the pre-1999 TCU Connector at C14, C15, & C16...Would appreciate any information on locating the connector diagrams or on testing the solenoids without going into transmission...Also, would appreciate any information/suggestions to troubleshoot my XJ's symptoms & Trouble Code P0751...Anyone in XJ Land delt with these issues...Thanking all in advance...Troubleshoot & test 1st - Spend $$$ 2nd!

IMPORTANT UPDATE: The information stating that the TCU was integrated into the PCM in 1999 is incorrect... Being a "Newbie" I guess I had to learn that you should not/can not believe everything you read in a Forum or on a Web Site... My Cherokee Sport does in fact have a TCM (Transmission Control Module) located under the dash above and to the right of the gas pedal... Attachment #1 is the TCM removed from my vehicle (two 8mm bolts) 298

Attachment #2 is a picture of the TCM "Pins"... The last 3 pins in the upper row, right corner, connect to the 3 Transmission Solenoids 299

Attachment #3 has two connector diagrams 300 The first is the TCM Connector... CAV 11, 12, & 13 are the 3 that should test 11-15 OHMS if each solenoid is good... The second connector is located at the transmission for the Transfer Control Assembly & testing could be done here as well; but, why crawl under the vehicle if it's not necessary...My 3 solenoids tested good at 11 OHMS each...Oh well, on to more troubleshooting... Hope this information helps others... Would appreciate any help, suggestions, or comments... Thanks, Ken

[Klaatu55]

Thanks