U0073 trouble code

[Michel67665]

My girlfriend has had 3 Saturn vehicles a 1991 four door sedan I forget the model, a 2001 Saturn SL1, and now the 2008 Saturn Astra XR. Awesome cars very reliable the 91 had 150k and was rolled on a sand road and totaled no injuries. The 01 is still running 170k. The 08 bought in august of 2008 has 99k on it. The 08 left us stranded, a 2 hour break down on a trip 2 hours from home right before a snow storm. No local mechanic or ford or chevy dealer could help us. Stopped to top off gas and would not start. Check engine light, oil light, and battery light was on. Checked oil, was full, checked battery condition, good, cleaned minimal corrosion on posts, tried jumping [was desperate] no difference. We ended up checking fuses I pulled out the diagnostic link connector in the trunk fuse block as my girlfriend was being directed by a friend on cell phone to move the seat, automatic gear shifter, and steering wheel tilt. Thinking it was some safety device that wasn't just right, well the car started so we came home, cancelled trip. Went to local auto parts store and they scanned trouble code, U0073 Control Module Communication Bus Off. So was wondering if anyone else has had same issue? Any help would be appreciated.

[phatfire6]

This may sound strange, but did you happen to check if your horn worked during this fiasco? This problem sounds related to the CIM (Column Integration Module). The code basically means that there was at least one full second where the CIM did not talk to the rest of the car. Your friend had the right idea about moving the steering column, as that is where it is located, but that certainly isn't a solution.

Once mine was replaced under warranty, the part is expensive. There is a recall for this part to install clips that keep vibrations from affecting the CIM and causing faults down the road - the US just never got them, Opel and Vauxhall brands did.

There are good reasons that your car won't start if this part is malfunctioning. Namely, the airbag won't work.

[Michel67665]

Thanks for the response we are on our way to the closest saturn repair facility. I will post how that experience turns out.

[Sleeper 64]

My car is showing the same code. What ever happened ? Dealer fix?

[Michel67665]

Okay I'm going to be the first to say it I'm inconsiderate. I did say something different the first time but my girlfriend said a rewrite was necessary. I am the kind of guy that will ask for help and not return it so here goes with the update for my girlfriends car. The dealer (I mean authorized Saturn repair facility ) was a very busy place. Lots of oil changes and general maintenance stuff. We were there early but our car sat for a few hours before looked at. Kind of like the doctors office wait. Running cattle, people, cars whatever through the corral. Was not a wonderful experience. Anyway they found several codes ( B004A , P0116, U2100, U2103, B1006, U0073, ) So no talk of repairing anything in steering column, they said we have to clear codes and reprogram ECM and TCM. It took them 3 times to reprogram the ECM and TCM they said if it didn't take the third time we were looking at new computer but it took alls well for about 25,000 miles. We had check engine light on for 1 day went off on its own now we have service engine soon light on and charging system light on or battery light on. What is the deal! The car has a 1 yr old battery and the belt has 28,000 miles on it. We will not be buying another Saturn maybe a Ford.

[Michel67665]

So here goes the update. Battery light was on so thought belt was slipping so replaced tensioner and belt . Turns out alternator was going out. Guess what we could not purchase an aftermarket alternator from the local part stores because no one makes them. It is a Bosch alternator made in Spain for the car. Well no one could even test the darn thing so I found an older gentlemen who rebuilds alternators he tested it and said it was bad so he tried to rebuild it. He couldn't get parts. Surprise! The Saturn repair facility quoted us $480.00 for a new one. Really! Ended up finding a new Oem alternator on line from New GM parts.com. Ordered it $291.00 to my door. First one was damaged sent back and got new one coming received it put it in myself had to remove air filter box, un bolt engine mount , remove front tire, and wheel well cover, to replace, used a 13/64 drill bit to hold tension off old tensioner and we had 16 trouble codes. Anything from low voltage to mass air flow sensor, cam shaft sensor, 02 sensors, and a few others. The car would not accelerate well, generally drove horribly. What is the deal. Went to check on how to reset ECM and ended up pulling ECM plugs and reinstalled. Still had 8 trouble codes so cleared them with scan tool and all is well. No codes and the car runs like a dream. I'm really surprised how touchy this car is with the trouble codes. We live in a rural area and it is 3 hours one way to the Saturn repair facility. So my advise to anyone with an Astra is to invest in a scan tool. Still trading in for new car.

[fdryer]

It doesn't matter where auto parts are made, what country they're made from. All car manufacturers as well as most large corporations have been outsourcing for years as a way to utilize 'world manufacturing' sources for reducing costs. Airbus uses parts manufactured all over Europe and East Asia and assemble these parts in France to make airplanes. The concept of business taking advantage of reduced costs while maintaining precision manufacturing is maintained. Its no different with Bosch alternators whether its made in Germany or anywhere else. My original alternator was made in Mexico and my replacement Bosch alternator is made in China. Bosch, like any company will use controlled manufacturing technology anywhere as long as it can be controlled while employing the lowest labor costs and parts to maintain competitive pricing. Quality is controlled if a name brand product wants its products well known and is quickly downgraded if quality fails.

Anyone searching for parts using ebay as opposed to the yellow pages from years ago will find parts made from overseas as well as here. ebay is a great source for parts when local distribution stopped. Lower overhead costs.

Astra is imported. Rebuilding may be difficult due to individual parts not stocked locally - difficult to buy specific alternator parts unless a source is found like ebay with world wide shopping at the click of a mouse.

Since our cars use more electronics, electrical demands are greater, placing more emphasis on reliable power. The battery, alternator and belt drive system plays a greater role to supply dependable electrical power now more than ever. As you found out, a failing alternator causes strange electrical issues with false error codes from a faulty power system.

[Fireklown]

I know this is old but it should help anyone who comes looking for answers. I Just had this problem with my 2008 Aura XR. the U0073 code refers to the Body Control Module not having a solid connection anymore. This causes a variety of problems that are not really problems. Here is a fix I found that worked like magic for me and anyone with a 2008-2009 Saturn Aura can do.

Remove the passenger side kick plate (Saturn hides your electronics here) If you are sitting in the passenger front seat, just to the Left of your Left leg is a "side panel" just below height of your ash tray. Pull gently from the front of this panel ,you'll see a small hole to grab,(velcro there) and gently unsnap a little at a time. Panel will come off.

Find the BCM module (you will see several fuses and connectors attached to it. Look for the two that appear to be housed by a small plastic harness(Mine had blue colored plastic). Fit a flat head screw driver into the latch, and unlock the plastic harness (it will slide upward over the module). You can then uplug the modules and you'll see numerous tiny thin metal prongs that it snaps onto. Get some DiElectric grease from you local parts store and take a small paint brush (1/4" type) and swab the grease onto each of the metal prongs. Snap the module in and out a couple times to spread the grease around, and then snap it in and lock it down. Do the same for the other module. Then put the panel back on and drive it. My problems were cured, I hope the same for you.