Superflyevo

Can anyone tell me where all the grounds are at on me 1999 grand cherokee?
When I got it I got the P0700 code said I needed a new TCM so I got a new TCM and now in still getting the same code... When I clear the codes for like the first 10 seconds I have 1st gear then the engine light comes back on and then I have no 1st or over drive . Over tryed putting in a new relay that didn't work either.. I'm thinking its something electrical.. The guy that had it befor me pulled the motor to rebuild it and I think when he put it back in either he messed up a wire somewhere Or he left a ground undone.... So like I said I'm hoping someone can tell me where all the grounds are so I c can check them all

Thanks pat

jnicewan

Since the tranny came from an overland I am going to assume the engine is a 4.7? I think the most important grounds are on the engine, but a couple others are on the inner fenders.

There are some ground wires on the RH (pass) side of engine block, basically right in the center of the block, behind the motor mount. In that area there are two different ground bolts and at least 2-3 circuits/eylets that should be grounded.
Another ground on the LH side of engine behind and below the oil filter near the pan.
Right behind the engine fuse box on RH fender and couple more on LH fender.

I would hate to see this but you might make sure you didnt pinch the trans harness between the bell housing and engine, I have done this before and it sucked bad. Hopefully you can take a peek up there and maybe poke the harness with a long screwdriver to make sure its not pinched.

Superflyevo

Thanks I appreciate the help looks like i got some work to do... If anyone else has any more ideas on y I'm having this problem feel free to share your ideas I'm willing to try anything!

Superflyevo

I checked to see if the TCM fuse is getting power and it is soooooo I'm loosening power somewhere between the the TCM fuse and the TCM it's self..... ANY SUGGESTIONS?

jnicewan

If I remember you already tried swapping the TCM relay with another known good relay right? If not try that first. Relays aren't too complicated but you will need to check a couple circuits to see if the relay has power and ground and check to see if the TCM is triggering the relay.

You should be able to remove the relay and on the side or bottom of relay you will either see a schematic or just pin numbers ( 30,85,86,87 ) these are the numbers you need to be concerned with.

pin 30 gets power from fuse #5-30A and should be hot all the time

pin 87 is the power circuit that the relay turns on when energized (3 red wires to TCM) this wire should show continuity to all 3 TCM pins mentioned above

pin 85 is the relay ground, should be grounded (this is one of the ground wires on the RH side of engine block) this wire should show continuity to ground

pin 86 is trigger circuit to engergize the relay to come on, this wire comes from the TCM its pin 15 at TCM and pink/yellow wire. (this should have power anytime the TCM wants the relay on, proabably anytime the key is on or engine running) this wire should show good continuity from TCM pin #15 to relay pin #86

A primitive test you could use to bypass the relay is making a short little jumper wire, you can put non-insulated male spades on the wire ends to stick in the relay cavities, or use bare wire but you might need a decent connection. The two circuits you want to plug the jumper wire into are #30 & #87. Connecting these two circuits are what the relay normally does when its engergized.

dave1123

Just a note; if using a jumper wire, make G** D*** sure you get the right pins!

Superflyevo

Ok so I tryed the jumper thing where I jumped a wire from #30 to #87 and what do ya know the TCM plug red wired have power! So what do I do now??

Superflyevo

So I think I need to figure out what sends the signal to kick the relay on and off

Superflyevo

I also used a test light connected it to the positive side of the battery and the touched the ground for the relay and the light didn't turn on... Shouldn't it turn on?

FAlfani81

Are you getting this code with the Key On Key Off? If so, you NEED to hook up to an actual scanner to get your correct code. When there is a Tranny problem in a WJ and you key on/off you will only get P0700 as a generic code telling you that you a tranny problem was detected.

I suggest using a scanner, finding your code. Then check the link below to find out what your problem really is before you make yourself go crazy over what might be a 2 second repair

http://www.wjjeeps.com/faultcodes.htm#0700

Superflyevo

Ok here's a question where EXACTLY is the ground for the TCM relay?

Superflyevo

We are useing a good scanner it's a snapon solus scanner.. And yes the key is on it has to be on to use that scanner..

jnicewan

I have a mitchell manual and it says the ground in on the RH (pass) side of engine, it doesnt have a specific pic of ground but I am pretty sure there are only two ground locations in that area, they are both right beside each other. I mentioned it earlier but these grounds should just bolt to the cylinder block right behind the motor mount.

If you are having trouble locating the ground and you know its an open circuit you could always overlay the ground circuit to the relay. I dont think it would be too hard to lift the fuse box and remove the bottom cover and find the black/yellow wire to the relay and splice in a new wire and run it to a good ground. I would suggest you peel the insulation back and solder a wire to the existing circuit without cutting it because I think this circuit is spliced to the a/c compressor too.

FAlfani81

I your only getting a 700 code it might not be reading the TCM codes and its just giving you the PCM code.

And when I say Key On Key Off I don't mean for the scanner.

If you Key On, Key Off, Key On, Key Off, Key On. Your fault codes will appear in the mileage.

jnicewan

He has another thread and said he's getting a P1768