no bus code on jeep Cherokee?

There is actually a TSB about this problem. You can remove the cluster and inspect the Chrysler Collision Detection bus circuit terminals. Check for darkened lines or darkened marks on the male pins of the cluster. If signs are seen then perform TSB # 08-15-99. At times, the Instrument Cluster Connector oxidizes and creates a poor connection causing this type of problem. If that does not seem to be an issue, then either the instrument cluster itself is bad or another module on the BUS system is shorting out causing this problem. This is very common on these vehicles. Any module on the BUS system can short out causing this type of problem. Here is a list of potential causes.

Air Bag Control Module
Instrument Cluster
Instrument Cluster Wiring
Overhead Console
Powertrain Control Module
Remote Key less Entry Module
Sentry Key Immobilizer Module
Transmission Control Module40692.9409896181

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Try to unplug the crank sensor and see if the no bus message goes away. The crank sensor is located on the drivers side between the engine and the transmission. The wiring will go to the passenger side of the back of the engine if the message goes away replace the crank sensor.-----------------

But if crank sensor wire is checked ok, then in most of the cases the instrument cluster or PCM or TCM needs replacing.--------

Instrument cluster panel is in need of a dealer item they call a "PIGTAIL".To install this part it requires tearing down the entire dashboard of your JEEP. It basically is the link between your engine computer and the dash. Little piece of plastic and wiring components.

There is a connection failure between the gauge cluster and the PCM. this NO BUS is often accompanied by malfunctioning gauges, the check engine light, and the airbag light, although exact gauges and lights may vary. THE SOLUTION in most cases is to remove the gauge cluster and clean the contacts of the cluster. The application of dielectric grease to the electrical contacts will also help greatly.

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Once the connection is passing voltage on all circuits, the gauges will imediately return to normal without needing a hard reset of the ECU.

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One more thing, ECU/PCM/ECM is name of one and the same thing.So please dont get confused.

First you will want to verify you have a few tools.

1) phillips screwdriver and a regular pair of pliers
2) long nose multi-purpose tool such as this one

here

3)

butt-connectors

, I used 16-14. Get a box of 100, as they are nice to have.
4) The connector which is Mopar part # 1-05016261AA. Get two of these from the dealership, $8 per.

The Service Bulletin:

NO: 08-15-99
SUBJECT: Erratic, Intermittent Cluster Operation/Intermittent Air Bag Warning light.
DATE: May 21, 1999
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN NUMBER 08-20-98 REV. A, DATED OCTOBER 2, 1998, WHICH SHOULD BE REMOVED FROM YOUR FILES AND NOTED IN THE BOUND TECHNICAL SERVICE BULLETIN BOOK, PUBLICATION NUMBER 81-699-99003. THIS IS A COMPLETE REVISION TO THE PROCEDURE.

OVERVIEW:
This bulletin involves installing a repair harness containing a revised instrument cluster connector.

SYMPTOM/CONDITION:
Some vehicles may exhibit an intermittent illumination of the air bag warning light or an intermittent tachometer or speedometer drop out. An Airbag Electronic Control Module (AECM) fault code -"No Cluster CCD BUS " message will be present.

DIAGNOSIS:
Using the DRB III®, read and record all active and stored fault codes in the AECM. This condition is caused by minor oxidation of the BUS circuit terminals at the instrument cluster connector. Electrical terminals will show signs of oxidation, which will appear as darkened lines or marks on the cluster male terminals. These often appear as gray or black marks rather than the appearance of oxidation or corrosion usually associated with higher current carrying circuits. This condition will set a "NO CLUSTER CCD BUS" message. The fault code will usually be stored and not active. THIS TECHNICAL SERVICE BULLETIN WILL NOT ADDRESS FUEL OR OIL PRESSURE GAUGE ISSUES. If this fault code is present, either active or stored perform the Repair Procedure.

PARTS REQUIRED:
Qty Part No. Description
1 05016261AA Cluster Connector Patch Harness
1 04856975 Electric Contact Cleaner
2 04778570 Heat Shrink Tubing

Here are pictures of the install procedure.

Step 1. DISCONNECT THE NEGATIVE BATTERY TERMINAL. Remove the dash. There are 3 screws on the plastic kickplate cover, 2 screws on the kick plate, and four screws for the gauge console cover. The center console, and the top portion of the dash simply pop out. You may have to remove the headlight plunger, however I was able to slide mine out without removing it.

Step 2. Remove the gauge cluster. There are four screws, then the gauges pop out of the connectors.

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Step 3. Crimp the butt connectors onto the new plugs. Then CUT ONLY ONE WIRE AT A TIME off the old connector. The colors may not match up on your model, so be very methodical on matching up the wires by location, not just by color.

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Connect your battery and turn the Ignition on.

After this the "No Bus" message should be gone. If this does not solve your problem, then there are a few other things to check such as:

CPS - Crankshaft Position Sensor can often cause this. Test your CPS, it's easily done with a multi-meter.

The guage cluster itself could be the cause (my issue ultimately). These can be found at junkyards or on ebay.

Possibly the wires from the ECM. Check these with a multi-meter for continuity, cracks, frayed wires, etc