Vincenza V

Is this common? What could cause this? No communication from the OBDII scanner.

My vehicle didn't start today, I had a "click-click-click" noise. I thought my starter was bad. I tapped it with a hammer, hoping it would fix it. Then I got back inside to try the key, but instead of the clicks, it was silent. No lights, clicks, or anything.

My mind flashed back to the NSS. I had it go bad and took it apart to clean it 6 months ago. The cleaning repair went so-so because it worked, but the piece the nut threads onto broke. The nut is held on by the metal lock ring.

I got underneath the jeep, and wiggled the NSS shaft. Went to start the jeep and it started (albeit-It chugged to life, I had to keep my foot on the gas to keep it running for a few minutes. Then it idled normal-but the CEL came on)

Any advice?

cruiser54

Bad battery and/or cables/connections.

CCKen

Some things you may want to check concerning no communication from/to the OBDII scanner:

Refer to the CCD Data Bus schematic below.

The scanner communicates with the PCM, TCM, and the Anti-Lock Brake Controller (if installed) on the SCI Receive and Transmit circuits.

First, visually inspect the pin cavities on the DLC using a bright flashlight and a magnifying glass, if required.

* Examine each pin cavity for corrosion. See if any pin cavities are enlaged from people shoving meter probes in them. See if any are pushed back out of detent.

*If there are problems with pin cavities 6 and 7 this may be the communication problem. If corroded, try cleaning them with CRC Electronics Cleaner. If the pin cavities are pushed back, you'll have to dismount the DLC and attempt to push the pin cavity wires back into place. If they are enlarged, a very small jeweler's screwdriver could be used to try and straighten them out (good luck here).

Next, check the power and ground circuits to/at the DLC.

*Using a voltmeter, touch pin cavity 16 with the meter (+) probe and pin cavity 4 with the (-) probe. You should see battery voltage (The DLC gets its power from fuse F17 in the PDC, which also powers the headlamp switch). If no voltage, probe 16 (+) and touch pin cavity 5. Still no voltage, probe 16 (+) and touch a gas pedal pivot bracket mount stud. If you have voltage now, the DLC ground wires at ground G102 on the engine block are disconnected or corroded. It's unlikely that both ground wires are broken (open). Visually inspect G102. Pic below.

DLC/CCD:



G102 (oil dipstick tube mount bracket stud):

CCKen

Also, check the chassis and engine ground circuits in the engine bay.

Using an Ohmeter do this:


This test checks the condition of the vehicle body ground connections and engine ground connections. This test must be performed with the positive battery cable removed from the battery.

Start: Disconnect both battery cables, the negative cable first. Reconnect the battery negative cable and perform the test as follows:

(1) Connect one ohmmeter test lead to the vehicle fender (bare metal). Connect the other test lead to the battery negative post.

(2) The resistance should be less than one (1.0) ohm.

(3) If the resistance is more than one ohm, check ground G100 and the braided bonding strap connected to the engine cylinder head and the firewall for being loose, corroded, or damaged. Repair or replace the ground connections if required.

(4) Repeat tests (1) and (2) going from the engine block to the battery negtive post.

(5) If the resistance is more than one ohm, check grounds at G101 for being loose, corroded, or damaged. Repair or replace the ground connections if required.

(6) Finish: Disconnect the negative battery cable. Reconnect positive battery cable, and then connect the negative battery cable.

G100:



G101:



Firewall bonding strap:

Vincenza V

Wow, great input!

I have a new (two weeks old) Optima, and I ran 2-4ga (the shop didn't have all 2ga) wiring on some of the battery wires. The ground from the battery to the block is 2ga, The positive from the battery to starter is new 4ga, as is the battery to the PDC (new 4ga).

I will definitely run this trouble shooting once I get out of class today and report back with the findings. Thank you so much!!!!!

This is my DD.

CCKen

Why AWG 2 and AWG 4 cables? That's an overkill.

OEM is 6 (+) and 8 (-). That's all you need for a stock XJ.

Vincenza V

Because I like overkill, lol. And I plan on doing a winch, tons of lights, and an inverter one day. My old wires were bad so I wanted to have as least resistance possible for the future mods.

cruiser54

Ken, could you submit this as a write-up for grounds on 1999 and whatever other years are the same?

Vincenza V

Some things you may want to check concerning no communication from/to the OBDII scanner:

Refer to the CCD Data Bus schematic below.

The scanner communicates with the PCM, TCM, and the Anti-Lock Brake Controller (if installed) on the SCI Receive and Transmit circuits.

First, visually inspect the pin cavities on the DLC using a bright flashlight and a magnifying glass, if required. Done, checked with magnifying glass and bright light.

* Examine each pin cavity for corrosion. See if any pin cavities are enlaged from people shoving meter probes in them. See if any are pushed back out of detent.None pushed back, all clean-but I cleaned them with electrical cleaner anyway

*If there are problems with pin cavities 6 and 7 this may be the communication problem. If corroded, try cleaning them with CRC Electronics Cleaner. If the pin cavities are pushed back, you'll have to dismount the DLC and attempt to push the pin cavity wires back into place. If they are enlarged, a very small jeweler's screwdriver could be used to try and straighten them out (good luck here).

Next, check the power and ground circuits to/at the DLC.

*Using a voltmeter, touch pin cavity 16 with the meter (+) probe and pin cavity 4 with the (-) probe. You should see battery voltage (The DLC gets its power from fuse F17 in the PDC, which also powers the headlamp switch). If no voltage, probe 16 (+) and touch pin cavity 5. Still no voltage, probe 16 (+) and touch a gas pedal pivot bracket mount stud. If you have voltage now, the DLC ground wires at ground G102 on the engine block are disconnected or corroded. It's unlikely that both ground wires are broken (open). Visually inspect G102. Pic below.Done, all check out good

DLC/CCD:



G102 (oil dipstick tube mount bracket stud):This checks out too


-When I was checking grounds, I did notice the ground from the battery negative, to the chassis completely loose. Both at where it bolt to the chassis, and at the terminal that connects to the battery. We were able to tug on it lightly and it came right off the terminal. After checking all the grounds listed here, this MAY be the problem, MAYBE. I drove to my brother-in-laws to use his code reader, and the CEL was still on on the way there (30 min trip). I shut it off and then 20 min later when he came home, I started the Jeep. I put the code reader on and it showed "0" codes. I asked to see the display. There wasn't anything saying it wasn't communicating with the Jeep, just that it said "0" for the codes. I told him my CEL was on the way over, he said it wasn't now. I looked up, sure enough, it went out. Maybe that loose ground was it? I went to my parents after. Had two more starting cycles and the truck started perfectly, no CEL either. I'm keeping both hands and feet with the appropriate fingers and toes crossed, but I'll let you know if anything changes. THank you so much for the help thus far!!!

__________________
If we have data, let’s look at data. If all we have are opinions, let’s go with mine.

CCKen

[QUOTE=Vincenza V;2613494I have a new (two weeks old) Optima, and I ran 2-4ga (the shop didn't have all 2ga) wiring on some of the battery wires. The ground from the battery to the block is 2ga, The positive from the battery to starter is new 4ga, as is the battery to the PDC (new 4ga).[/QUOTE]

Curious...

What did you run from your alternator to the bus connection at the PDC?

Vincenza V

I'll check later. I don't remember if I got to that one or not. There was a limited supply of 2 and 4ga wire at the shop I went to. If it is still stock, is that something I might as well match to the 2/4ga I have now? Thanks.

CCKen

Don't forget, there's a fusible link in that cable that goes from the alternator to the PDC bus. Take a look at the PDC bus hook up - there's a chunk of Green wire that hooks up there (the fusible link). I can't imagine where you'd find an AWG 2 fusible link. The link is a must BTW.

CCKen

I just saw this...LOL

I'll give it a try.

This data covers 1997 thru 2001 XJ's. I'm not sure about 1996. I don't have the FSM or photos of the engine bay ground points so I guess I'll leave it out.

cruiser54

97-01 would be great to have!!

CCKen

More data concerning fusible links:

http://www.whiteproducts.com/fusible-faqs.shtml

Note that a stock (97+ XJ uses an AWG 6 cable from the alternator to the PDC with a AWG 10 fusible link before the PDC connection.