Anyone know about this code? U0073

So I got this code today. Anyone know anything about it?

Doesn't Sound Good...

http://www.subaruoutback.org/forums/66-problems-maintenance/30755-code-u0073-cel.html

I saw that. I also saw this too.

U0073 - Definition: Control Module Communication Bus "A" Off

U0140 - Definition: Lost Communication With Body Control Module

What needs to happen is the cluster can be commanded to sweep gages using the GM Tech 2 scan tool. Keep in mind that the gage testing and any programming needs to be done at a GM dealer using the GM Tech 2 scan tool. If they respond correctly to that command that means the gages and wiring to the gages is fine and the part(s) responsible for sending info to the gage is inaccurate. If they don't sweep ok then suspect a faulty cluster. To do the sweep test it needs to go to a GM dealer though. The gages not being accurate is common on the older year trucks and a cluster is the fix (along with programming the new cluster using GM software).

Check this information about #PIT4730: Additional Diagnostic Information For U0140 Or U0073 - keywords BCM comm communication cycle DIC door freeze gage gauge inop inoperative int intermittent LAN locks message no service speed speedo - (Oct 3, 2008)

Subject: Additional diagnostic information for U0140 or U0073

Models: 2008-2009 Buick Enclave

2006-2009 Buick Lucerne

2006-2009 Cadillac DTS

2007-2009 Cadillac SRX

2008-2009 Cadillac CTS

2007-2009 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2006-2009 Chevy Impala

2006-2007 Chevy Monte Carlo

2008-2009 Chevy Savana

2007-2009 GMC Acadia, Sierra, Sierra Denali, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL

2008-2009 Hummer H2

2008-2009 Pontiac G8

2007-2009 Pontiac Torrent

2007-2009 Saturn Outlook, Vue

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern: Some customers may complain of one of the following symptoms:

• Door locks cycle while driving

• Intermittent No Start

• Service Stabilitrak DIC message

• Speedometer and tachometer freeze while driving

Along with these complaints DTC U0140 00 and/or U0073 71 may be stored as a history code in any GM LAN High Speed module.

If the data circuits (2500 & 2501) have experienced an "intermittent" short to ground or short to each other "2 times" within a period of less than 1 second and then go back to normal, the BCM may appear to be "off-line" on the high speed buss. This intermittent scenario should not cause other modules to lose communication, only the BCM. If this situation happens, the BCM will not start communicating with other modules again until the key is out of the ignition and the BCM has timed out (approximately 20 minutes).

Typically the customers complaint will be intermittent and usually occur when driving over bumps/rough roads.

Recommendation/Instructions:

If DTC U0140 00 or U0073 71 is set only as a HISTORY code in any of the high speed modules, refer to "Testing for Electrical Intermittents" in the service manual to reset the DTC and diagnose the location of the fault.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

Also coudl visit your delaer and ask fot this Bulletin:

TSB Number: 08-07-30-021 NHTSA Number: 10025402 TSB Date: April 1, 2008 Date Added to File: August 6, 2008

Failing Component: Engine And Engine Cooling:Engine

Summary: Loss of high speed gmlan communications, intermittent no crank, ipc gauge fluctuation, intermittent door lock cycling, transmission may not shift, DTCs U0073, U0100, U0101, U0102, U0140 (repair backed out terminal in transmission harness connections).

Test it and lkeep us updated.

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I read also a wiring problem. I would go to the dealer and see if they can figure it out.

Joe does your car have the Subaru remote start?

Negative, I talked to Bren and he said just clear it. I cleared the code and it never came back. I do have halos and supertones. Wonder if something was jarred after that bump.

Halos and supertones wont have anything to do with it. Its a data bus between the ECM and body computer. I dont think any of the auto manufacturers have the serial data stuff completely ironed out. Its too finicky and easily spoiled. If encoded messages aren't perfect it pops codes.

For instance. .. we had a Tribeca with tranny codes and bus codes, tested wiring, computers, and communications. Changed a harness, changed the tranny computer. Codes kept coming back. In the end we swapped the new tranny computer with one from another Tribeca and both Tribecas were good to go after that. Subarus are especially difficult because the same thing doesn't happen to all the other ones like GMs. WIth Subarus its always a new journey down the U-code path.

Wow, hopefully it does not come back. I'm keeping my fingers crossed!

So this keeps coming back. I'm really not looking forward to bringing it to the dealer either....

I think you should, the sooner the better. And please please please bring it to Evergreen. I don't say this because they are our sponsor, (We get nothing for service referrals anyway) I say this because Joel will make sure it is fixed. This error could lead to a lemon, don't take chances.

Is evergreen mod friendly? Not that I have a lot. I just don't wanna have to get retuned.

Gretsch308 said:

Is evergreen mod friendly? Not that I have a lot. I just don't wanna have to get retuned.

Click to expand...

Extremely mod friendly.

Good luck getting this figured out Joe!

I don't want to jynx myself(knock on wood) but I beleive I found the enabling cause for this. Still looking into the root cause. What I beleiv eit to be is, I had the GL1 cable always plugged into the OBD-II port. Even when I was not using it. I have had it unplugged for some time and the code has not returned. I think I got this code 5 times while it was plugged in. I still don't know root cause but I am guessing faulty cable or OBD-II port. We will see what happens. I am going to do some more research on this cable to see if anyone else has had this issue.

Gretsch308:

I'm experiencing the same problem with my new ScanTool OBDLink MX bluetooth OBDII adapter with the Torque app on my Galaxy Tab. One person said the problem may actually be with the software (the Torque app) and not the adapter. I'm still in the process of troubleshooting.

Did you ever figure out what was causing it? Were you using any software to interface with the GL1 cable?

Not yet. I know for a fact it is the cable and not the software. The code would pop with out the software being loaded on the phone. I sent the company an email. They never responded.

I was using Dashcommand for iOS.

Gretsch308 said:

Not yet. I know for a fact it is the cable and not the software. The code would pop with out the software being loaded on the phone. I sent the company an email. They never responded.

I was using Dashcommand for iOS.

Click to expand...

well there's your problem. Get rid of the stupid apple stuff and you'll be all set! kidding. Hopefully you can get it sorted out fully. Sucks that you were having issues though.

Good point Gretsch. I should also try seeing if the problem happens with the adapter plugged in but no software communicating with it. That would peg the problem to the adapter and provide a good argument for a refund.

Such a bummer though. This adapter costs $250 ($150+ more than the next one down) and was supposed to the best of the best...

FierceElements said:

Good point Gretsch. I should also try seeing if the problem happens with the adapter plugged in but no software communicating with it. That would peg the problem to the adapter and provide a good argument for a refund.

Such a bummer though. This adapter costs $250 ($150+ more than the next one down) and was supposed to the best of the best...

Click to expand...

To further elaborate the code was popping when the just the GL-1 was plugged in. I did not even have the phone hooked up. Just the cable plugged in and stuffed under the steering column.