99 xj, dealer DRB3 won't communicate..

OK guys 99 xj 4.0 when purchased from previous owner, no carpet no seat belts, cut up fenders....wheeling rig. Anyways fixed all that, been driving it everyday for the past 3 years. When i bought it he gave me a keyless entry factory key fob. That didnt work. So new battery's still didn't work. Took down the dome light and notice the keyless entry computer chip was missing. So new one from the jy and still didn't work. Well didn't worry about it for a couple years. Went to my buddy at the dealer today to have them program the key fob. So they took it back hooked up the drb3 and could not comminicate with the jeep at all. Couldn't program the key fob , couldn't access the motor. Nothing they would not talk to each other.

So I asked the tech, I said I can use my obd2 reader to clean codes on it no prob why can't the drb 3 communicate. He said on the obd2 connector, there are 2 different bus wires one for the drb3 to communicate to and one for aftermarket obd2 readers.

So I can pay the dealer money to figure out the prob ( not going to happen), so I'm asking for halls help, the tech told me a bad ground could cause it, really it could be anything, he said. So where do I start and what do I look for. And BTW I have the 99 factory service manual book.

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From a Jeep tech friend of mine. If the DRB won't communicate, unplug the CPS connector first and see what happens.

X2 on checking the cps. Sidewaysstarion here in socal is the go-to drb expert, and my 98 recently wouldnt read codes. Cheap craftsman scanner, or expensive dealership drb tool, neither could connect.Turns out the cps was shorted to ground. Replaced the cps and both readers could connect.

OK thanks guys, i was able to mess with it today. I first when out and pluged my obd2 cable that goes to my laptop, ran the scan tool program and it connected fine ( no codes), and was able to watch sensor data. So I think my CPS is fine.But I also went ahead and cleaned up the 4 ground wires on the driver fenderwell near the computer. Also I remembered when I bought the jeep the downstream o2 sensor (the one after the cat) had electrical tape on the wiring , but at that time I just ignored it. So today I looked at it, It looks like the PO replaced the o2 sensor with a FORD o2 sensor and just cut the pig tail from the o2 sensors and swaped the pigtails to make the ford one work with the jeep. Now the wiring colors on the jeep o2 pigtail and the ford o2 sensor are the same: 2 Whites, 1 Gray, 1 Black. They were wired the same. But could the problem have been the 2 whites being swaped. Or just could the ford sensor cause this problem.

Well I remember hearing a while back that some 99 XJ had a programing flaw in the computer that didnt even read the downstream o2 sensor so in turn even if it was bad it wouldnt throw a code or check engine. So I disconnected this FORD sensor and the jeep still runs fine. And I get NO codes or check engine.

But the Overall question is did I even fix the issue for the DRB 3 to connect????

theviper90210 said:

OK guys 99 xj 4.0 when purchased from previous owner, no carpet no seat belts, cut up fenders....wheeling rig. Anyways fixed all that, been driving it everyday for the past 3 years. When i bought it he gave me a keyless entry factory key fob. That didnt work. So new battery's still didn't work. Took down the dome light and notice the keyless entry computer chip was missing. So new one from the jy and still didn't work. Well didn't worry about it for a couple years. Went to my buddy at the dealer today to have them program the key fob. So they took it back hooked up the drb3 and could not comminicate with the jeep at all. Couldn't program the key fob , couldn't access the motor. Nothing they would not talk to each other.

So I asked the tech, I said I can use my obd2 reader to clean codes on it no prob why can't the drb 3 communicate. He said on the obd2 connector, there are 2 different bus wires one for the drb3 to communicate to and one for aftermarket obd2 readers.

So I can pay the dealer money to figure out the prob ( not going to happen), so I'm asking for halls help, the tech told me a bad ground could cause it, really it could be anything, he said. So where do I start and what do I look for. And BTW I have the 99 factory service manual book.

Sent from my Nexus 7 using Tapatalk 2

Click to expand...

You say your OBDII Code reader/scanner can communicate with the CCD Data Bus through the Data Link Connector (read codes and delete codes)? Can it still do that?

"He said on the obd2 connector, there are 2 different bus wires one for the drb3 to communicate to and one for aftermarket obd2 readers."

I think he's a little off there. The OBDII XJ DLC has two wires to communicate with the CCD Data Bus [a (+) and a (-) circuit] and two wires to process Serial Communication Interface (SCI) data [SCI Transmit and SCI Receive circuits].

The XJ Cherokee never did use a "SCI Bus" like some other Chrysler products. These SCI Bus vehicles will have a dedicated pin cavity on the DLC for this bus (pin 2), which the OBDII XJ doesn't have. The tech may not have set up his DRBIII tool properly (Your VIN) before connecting it to your DLC, and his DRBIII was looking for pin 2 on the DLC. (?)

The OBDII XJ Cherokee has three modules with SCI transmit capabilities (send data to the DLC), the PCM, TCM, and the ABS CAB (if installed). The PCM has the only PCI Receive circuit (receive commands from a code reader/scanner, such as clearing codes, and programing keyless entry modules).

If any SCI transmit or receive circuit is open or shorted to ground there will be a No Communication issue.

If the CCD Data Bus is down you won't have instruments and other functions. If your XJ starts, has full instruments, and all other circuits function properly, the CCD Data Bus is intact. However, the SCI circuits still may be open or shorted and not affect the operation of the vehicle.

Thanks for the long explanation, yes the jeep runs fine and everything works fine, and yes I hooked up my scanner today like I said in previous post and it worked fine before and after doing the stuff I did. This is where I stand now is will it work with a drb3, I would hate to go wait at the dealer again to program the key fob and the drb still not communicate. Anything else I should do or check?

theviper90210 said:

Thanks for the long explanation, yes the jeep runs fine and everything works fine, and yes I hooked up my scanner today like I said in previous post and it worked fine before and after doing the stuff I did. This is where I stand now is will it work with a drb3, I would hate to go wait at the dealer again to program the key fob and the drb still not communicate. Anything else I should do or check?

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Is there another dealer near you that you could call and talk it over with them. And see if they will hook up their DRB III and see if it works...free of charge. If it does work, then have them program it. I paid $50 for one of my local dealers to do mine. Rip off, but what was I to do.

Question: What code(s) did you have that you cleared? What work did you do that fixed this/these code(s), then cleared them.

No codes except when I first bought it but I don't remember what that was, but my scanner will read for codes and shows live sensor data when its running. So I know my connection works, just need to get a drb tested.

There is another dealer just don't know anybody there.

I had a similar issue with my friends 01 xj from back east (has minor rust problem), it turned out the pins were corroded and after plugging in and unplugging my DRB a few time it finally connected and I was able to talk to the ECU. Have you had your friend try to access any other modules in the car besides the ECU?

Also make sure your friend is using the proper CH7000 cable like this one.
http://www.ebay.com/itm/NEW-CHRYSLE..._Automotive_Tools&hash=item1e774e1a6f&vxp=mtr

sidewaysstarion said:

I had a similar issue with my friends 01 xj from back east (has minor rust problem), it turned out the pins were corroded and after plugging in and unplugging my DRB a few time it finally connected and I was able to talk to the ECU. Have you had your friend try to access any other modules in the car besides the ECU?

Also make sure your friend is using the proper CH7000 cable like this one.
http://www.ebay.com/itm/NEW-CHRYSLE..._Automotive_Tools&hash=item1e774e1a6f&vxp=mtr

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I had a problem with my DLC when I bought a scanner and tried to use it for the first time. It wouldn't power up. Pin 16 was corroded so I did like you, plugged it in/out/in several times and it then fired up.

Might try your local community college. The ASE program I'm attending at my local school has a DRB III, along with other major scan tools and we offer services to the public for the cost of parts only. An eager instructor or student might WANT your vehicle to learn from as they get familiar with the DRB. I'll be using the one we have in the coming weeks to program my keyless entry remote for free. The dealerships are a rip off any way you slice it. Just my $.02

Check the lighter fuse

theviper90210 said:

So I disconnected this FORD sensor and the jeep still runs fine. And I get NO codes or check engine.

But the Overall question is did I even fix the issue for the DRB 3 to connect????

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This dosen't sound right.

Try inducng a Trouble Code by disconnecting the engine coolant temp sensor, turn the key to run, see if you get a CEL. Reconnect the coolant temp sensor and hook up your scanner. You should see a P0118 code. Try to clear it if it's there. If all this works, your CCD/PCI system works.

Sidewinder, drove the jeep to work today with the downstream ford o2 sensor unplugged. Jeep did fine no codes, then about 25 mins or so into driving, check engine light finally came on. Jeep still ran fine for the next 15 mins to work. Ill check the code tonight when I get home, but I'm sure it will be that sensor being unplugged. So I guess my ecm is reading that sensor like its supposed to.

Let me ask you this, I also took the o2 sensor out the pipe and looked at it, its nasty and dirty also the little "cage" around the sensor bulb is kinda crushed in toward the bulb. Could that possibly be grounding out the sensor and therefore causing a grounding issue to the dlc for when the drb is trying to connect?

theviper90210 said:

Sidewinder, drove the jeep to work today with the downstream ford o2 sensor unplugged. Jeep did fine no codes, then about 25 mins or so into driving, check engine light finally came on. Jeep still ran fine for the next 15 mins to work. Ill check the code tonight when I get home, but I'm sure it will be that sensor being unplugged. So I guess my ecm is reading that sensor like its supposed to.

Good, now see if you can clear it with your scanner - after you replace that O2S.

Let me ask you this, I also took the o2 sensor out the pipe and looked at it, its nasty and dirty also the little "cage" around the sensor bulb is kinda crushed in toward the bulb. Could that possibly be grounding out the sensor and therefore causing a grounding issue to the dlc for when the drb is trying to connect?

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A shorted out O2S can cause problems in the PCM, but I'm not sure that this buggered up O2S will cause your OBDIII problem. Change that sensor, as well as the upstream O2S. Recommend using NTK sensors (OEM original install). Also check the O2S heater fuse in the PDC after changing out the O2S's. Let me know if you need a pic to find it.

A Ford O2S? WTF? Bubba sure was working overtime to install that!

The two white wires from the O2S are for the O2S heater. They are not polarity sensitive. One is power in (from the ASD) and the other is ground. One white wire goes to the body harness wire Dark Green/White tracer and the other to Black harness wire.

The Black wire from the O2S goes to the body harness wire Tan/White tracer. The Gray wire from the O2S goes to the Brown/Yellow tracer harness wire.



NTK Upstream part number 23151, NTK Downstream part number 23099.

Thanks sidewinder ill get back to you when i get it all fixed. Thanks man

Yes, sometimes it takes the PCM a while to throw a code for an unplugged O2 sensor.

Talyn said:

Yes, sometimes it takes the PCM a while to throw a code for an unplugged O2 sensor.

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Tayln,

How's your Viper ignition system working so far?

Working fine, not a single problem. And I can put a timing light on it now as well as pull a single plug.

Will I have any problems not running the downstream o2 till I get them replaced. And do u see any prob getting the ntk sensors from rock auto vs the dealer, there like 32$ apiece on rock auto?