Try the cigarette lighter fuse

I have let this issue go. I need to look at it again tho. And I will. Last time I checked all my fuses are perfect. Still would not connect. I used a cheap hand held scanner, my own, and a snap on one....the dealerships. Neither would connect. I was told by a fellow mechanic to start looking at the wiring. But I let it go. At the time I posted this thread there was no check engine light. I have since broken the secondary oxygen sensor and now the check engine light is on. But I know what it is. Only problem is when some thing else goes wrong I will be stuck. So I will look into it more. I have since purchased more electrical tools that will help me figure this out. May take a few weeks. Since I will only be able to work on it here and there. And I just purchased another car that needs work. So that one comes first.

Can not connect and can not communicate are different issues.

Connect is usually a power/ground fault. The scanner/reader needs 12 volt battery voltage and a ground to connect. It then needs a clean connection at the DLC to communicate with the PCM and TCM through the SCI circuits.

Some scanners require configuring it before it will move ahead. My scanner has a nice list of vehicles and their motors etc., that need to be loaded.

I don't know about the '96 but the '97 and up, have a ground stud at the oil dipstick tube bracket that is the ground(s) for the DLC. There have been cases where the ground wires weren't even hooked up, and others that were badly corroded, causing a no connect situation.

No communication issues were that the scanner/reader was simply a POS and had no ability to communicate.

Condition of the pin cavities on the DLC are worth looking at. Corroded pin cavities are a possibility, enlarged pin cavities from bubba shoving meter probes in them are a possibility, pin cavity connectors shoved back from bubba again, are another possibity that may cause no connect or no communication.

Power to the DLC is tapped off fuse F17 (headlamp power) in the PDC for '97 + XJ's.

Thanks for the info. To clarify....my cheap hand held scanner will connect and start to load. Then stop and say communication has failed. Turn vehicle off and try again. I will try a better scan tool. Also look at the grounds.

Bringing this thread back...
Tried connecting to a 1998 Jeep grand Cherokee with elmscan device and scantool.net software. No connection to vehicle.


Tried the FORscan software, no connection to vehicle.
'Tried both on a 2003 Ford Taurus, 1997 F150 worked fine.
Also used the same elmscan device on 2006 Chevy cobalt.
Now, when the elmscan device is first plugged in to the Jeep, the power light comes on, so fuse is OK.
When the elmscan device is connected to the PC com port, all TX/RX lights flash once


Next, tried a Actron handheld and it goes..
cannot connect in automatic mode switch to Manual Y/N
Switched to manual
entered vehicle type
connected and communicated fine.


I do know the ECM in the Jeep is a 'remanufactured' unit.
So, it looks like the software and hardware has to have a manual option.
Any thoughts?

my cheap innova i have to have the key only in the run position, by better innova i can read any key position or engine running...just throwing it out there

I just had the same issue on my 2001 XJ. The OBD2 port has power so I know it isn't a fuse or ground issue.
after cleaning the contact pins, connecting and disconnecting the PCS, resetting the ECU, and everything else mentioned in this post I still had a "No link" message on my scanner. The only thing that worked for me was to disconnect the ABS module. The relay in the fuse box can be removed to turn the ABS dash light off.

Hope this helps.

I have a 2000 XJ with the 6 cylinder 4.0. And my check engine light turned on the other day. I used my bluetooth reader ELM 327 I think itīs called.
I do connect and readīs but it doesent show any codes at all. And I canīt turn the check engine light off ether because it does not show any codes.