adanrott

Vehicle : 2000 Jeep Cherokee 4.0l
Miles : close to 200k
Problem: no bus error on dash

Believe me, I have searched and searched for weeks to try and fix this error, I have tried everything I can think of, took it to 2 different shops, and both of them are at their wits end now. Spent hundreds, nothing will work.

Background - Heat wasn't working so I took it in my shop and blew out the lines, heating core, etc, and flushed the system, so after the heat worked great. My fiance drove the car home (1 hour away). It sat for a few hours. She started it up and on the way to driving it to work got the no bus problem (gauges all dropped out, airbag light, engine light came on).

Next day I searched online and found there were a lot of threads on numerous forums about this error. I went through all the steps I could find for answers.

- Checked all the fuses, everything there is good, no problems.
- Checked all the ground's, everything is good, the shop has even replaced many of the grounds in the engine to see if it helped.
- Pullled the cluster out and replaced the connections, didn't help.
- Replaced the cluster itself, didn't help.
- Put a new battery in, didn't help.
- The shop just told me they replaced a few modules like the airbag module and something else, but that didn't work either.

Now, neither of the shops/mechanics I've taken it to can find anything wrong with it, and I have tried literally everything I can find online to try and fix it.

I'm hoping someone here has some type of suggestions.
As it stands right now, I'm about ready to sell it if no one can figure it out.

fishtaconc

https://www.cherokeeforum.com/f2/no-...-tried-110670/

adanrott

Not trying to be a dick but I doubt you even read my post. I had already read that thread, and I have put in a new cluster, and new connectors/harness, and new grounds and a new airbag module. Nothing works. I'm taking it to a 3rd mechanic today, then a jeep dealer, then the junk yard if no one can figure it out. Already dumped close to a grand into it and I'm no closer to fixing it than the day it happened.

residentg

Not sure where you live, but there is a dealer in NY that has a mechanic that works magic on Cherokees. His name is Ray and he has been there for 18+ years:

http://suresky.com/Department-Service.aspx

Good luck with it.

bsmith97xj

The 5 volt sensor supply is shorted to ground. Most likely suspect is the crank sensor. Easy test, get a volt meter(not a test light) and unplug your tps sensor. Obtain a wiring diagram and determine which wire of the 3 is 5 volts. Check that wire with key on. Should be close to 5. If not start unplugging all 3 wire sensors till it comes back. I would start with crankshaft position sensor.

gary s

When you say the heater was worked on do you think that they may have taken the dash apart to get to the heater core? The reason I ask is because last summer I had my evaporator replaced and after words I had a no bus. Did pretty much everything you did,pulled the dash changed connectors etc. Ended up going to the dealer which I should have done in the first place,they pulled the complete dash out and found 3 crushed wires in the evaporator area. The shop who changed the evap ended up paying for the repair.

adanrott

Thanks for the replies. Would it be the cps though since the car starts up and runs? I'll check it though.

The dash was never taken apart for the heater. All that was done was the lines were taken off of the engine that go to the heater core and they were blew out since they were plugged. Then the radiator was drained, flushed, blew out, and the reservoir cleaned. I did all that myself, and have done it before on other vehicles no problem.

I just can't even think of what else to check right now, it feels like I've done everything so far.

tjwalker

No.

There are two types of NO BUS errors. Ones where the engine doesn't run (usually the crank sensor shorted) and the other NO BUS error where the engine runs which is what you have, which is a problem related to the cluster.

You have a tough one for sure. If you have a wiring diagram and a meter, you could try to follow the wiring for the cluster; that is about all that is left.....

Keep us posted.

DFlintstone

Issue is out of my league, but I've been reading allot. Gauges don't work? Just a harmless 2 minute test, try unplugging the CPS and check them again. Also consider that it's a 1/2 hr job, and a very important part. If swapping it doesn't help, it's nice to have a spare.

adanrott

well my mechanic said he thinks he fixed it. Some module on the steering column? Not sure the name of it, I'll update this when I talk to him, if it even is truly fixed. Last time he said it was fixed it didn't last 20mins before the error came back.

DFlintstone

Power Control Module? That would have been a bit spendy....

CherokeeChick33

Just curious if you had figured out the issue. My 99 wont run so i'm leaning towards the crank sensor but was curious as to the fix of your 2000...

tjwalker

CherokeeChick, if your engine doesn't run and you have the NOBUS, then the crank sensor absolutely is the primary suspect. If the sensor shorts out, it will create the NO BUS message and no-start condition. Theoretically any of the 5 volt engine management sensors could fail in this manner, but the crank sensor is the most susceptible to this type of fail.

Here is what you need to do. The connector for the crank sensor is under the hood near the firewall/#6 injector. Unplug it. NOW go and turn the key to the on position. This quick and easy test will take you all of 2 minutes.

If the NO BUS message is gone, then you have proof positive that the crank sensor is the culprit as you took that sensor out of circuit. Then all you need to do is install a new crank sensor. Do yourself a favor and buy it directly from your local Jeep dealership. Aftermarket crank sensors are "hit and miss" with a lot of miss. I won't install or recommend anything but a Mopar OEM crank sensor.

If disconnecting the crank sensor doesn't resolve the NO BUS, then one by one disconnect every 5 volt sensor one by one and check the dash for the NO BUS message every time, reconnect and move onto the next sensor. I've seen a bad computer also create a NO BUS.

But gotta start with the crank sensor as it is quite common. Good luck and keep us posted!

CCKen

If you have the Sentry Key Immobilizer system in your Jeep, it was probably the Sentry Key Immobilizer Module (SKIM) that he replaced. It's mounted on the steering column at the ignition lock cyclinder.

This module, and several others (see schematic below) are connected to the CCD Data Bus, and if defective can corrupt the CCD Bus and cause problems, such as a No Bus.

The mechanic probably read the voltage on the CCD Bus (+) and (-) at the DLC and found that the voltage was outside the 2.5 volt range then started disconnecting modules until the voltage problem went away.

sean21

Any updates?