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CTS 2008
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Discussion Starter #1
I've got an 08 CTS DI vin V. The other day I started getting a Service Power Steering message. It was intermittent and I drove it for a day. The power steering would work most of the time, but every now and then the power steering would go out and the message would pop back up. The voltage would report 11.x to 14.x while driving. Dropping down while idle.

I also had a whine coming from the alternator and a slight burning smell that I couldn't pin point the origin of. The smell seemed electrical.

Later that night I turned at a stop light and then got on it pretty hard. The car accelerated for a moment, then stopped. The display said it was in low power mode, but when I looked at the RPMs it was at 0. I pulled over to the side of the rode and shut the car off. When I tried to turn it back on I could not get it to crank. The screen was displaying Service Traction Control, Stabilitrak Off, and the service engine light was flickering very rapidly.

Towed her home, then to the dealer the next day. The dealer said they could not communicate to the ECM. $955 later and a new ECM installed, they were able to get it to start. They did identify that the alternator was not charging under 2,000 RPMs. I picked up the car and drove less then a mile around the corner to have an ProStart remanufactured alternator installed by pep boys for $300. I picked it up from pep boys and drove home. No more whine sound. All was well. I watched the voltage meter on the drive home and it was pegged around 14.8 or 9.

I parked in the garage for an hour or so. Hopped in to go get dinner and tried to start it. It cranked a few times, then lost electrical connection. All dash lights and radio shut off for a second. I waited a few seconds and tried to restart it. It cranked and sounded like it was starting, but was extremely rough sounding so I quickly shut it back up. Understandably upset, I screamed some expletives and went to get dinner in the Sierra. Got home 45 minutes later and the CTS started fine. But now it is saying Service Battery Charging System.

Any suggestions of where to look next? This gremlin is a pain.
 

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2008 CTS
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151 Posts
I would start with a new battery, I've heard of all kinds of strange electrical issues happening when the battery starts to go.
 

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'12 CTS Performance Sports Wagon AWD
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Sound like you may have had a bad battery that took out the alternator due to being over worked and when it died it took out your BCM.

Would replace the battery as suggested and see what happens. Might also want to inspect the wiring at the alternator and insure that the wiring isn't damaged or burnt from the old alternator.

Normally when a battery is dying you will get some strange codes in your car. Maybe your alternator just bit it all on its own. Could have lost a diode or more which would allow it to show proper voltage but not putting out good amperage and lots of noise. The noise can kill components. The battery is supposed to filter out the noise but if the battery wears down due to a bad alternator... Hard to say. And the electronics in these newer cars seem much more sensitive to voltage spikes and low voltages etc.
 

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Cadillac ATS Coupe 3.6 Performance AWD
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Did you ask for the original ECM when it was replaced? It sounds like that wasn't the culprit after all.
 

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CTS 2008
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Discussion Starter #5
The fusible link ended up blowing in my CTS. I think it happened after I put on a new alternator. Pep Boys was able to get the part from the dealer and installed for $120.
 

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2009 CTS
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chevyfamily, do you know what ended up being your fix for this? Also what kind of codes did you have?

I have a 2009 CTS DI. A couple days ago I got the same power steering message and power steering has been intermittent for the last couple days. I have also noticed my Voltage fluctuating from 12.5 to 14.6 up and down as i drive. I thought my "whining" noise was my PS pump, but perhaps not. I just flushed my PS fluid this morning hoping that will solve my issues. I do feel like it is an electrical issue though.

I just replaced my battery between 12 and 18 months ago.

My codes are C0450 and P2601 (may or may not be related)

Not sure where to start on this. My new dealership charges $125/hr for troubleshooting.
 

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08 CTS DI
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"Walk" with me for a moment regarding the experiences and comments above. I have more than 20 years of experience and exposure with automotive problems and repair although not as a mechanic. That's to establish that I have seen a LOT in the industry.

What motivated me the most towards learning to repair my own automobiles was a a number of bad experiences with the professionals, one in particular that turned a $65 repair; Chevy diagnostic fee plus the appropriate part, into a $265 repair when the Tech failed to do the most basic of checks during the 1 hr of diagnostics I paid for and instead read the code and performed no investigation. I ended up replacing a $200 MAF sensor instead of the $15 relay that turned it on, which was the problem and could have been tested in the minute it would have taken to swap it with the identical next to it.

Whining is a tell tell sign of a dieing, or dead alternator when it makes that noise. An extremely hot battery wire and its terminal at the alternator is often a side effect from it and it is possible that it may get so hot at the alternator connecting stud as a result of the failing alternator, it may end up damaged to the point of needing to be replaced, even if it still appears to be intact. When I think about it, perhaps it is a deteriorating connection at that point from age and possible corrosion, that leads to failure of the alternator from being ramped up in an effort to force sufficient current through.

If you connect a good alternator to such a wire, you will likely have intermittent to immediate problems. If that wire is fine at replacement alternator install and someone forgets to tighten it sufficiently, chances are it's going to get extremely hot and may burn to an extent that severely impedes current flow. Understand that this wire supports upwards of 135 AMPS, almost as much as my little MIG Welder so we're talking some serious current. The burning smell may have been coming from that battery wire all along.

I had a similar incident following an alternator replacement some years ago. The battery wire was loose at the alternator, the voltage regulator by what mechanism I do not know, responded to the poor connection by increasing its voltage output. I was driving home from Atlanta to Tampa at the time when I smelled the characteristic odor of burning electronics that seemed to be coming from the radio which I turned off. Then I noticed the voltmeter was higher than it had ever been and then the engine light came on. I had too far to go and wasn't stopping voluntarily because the car was running fine. I turned on the headlights to tug at the voltage and that seemed to settle things down. After arriving home I checked the alternator and found that wire was loose, a similar problem develops when there is a poor connection at the battery.

The alternator is pulse width modulated so its output is controlled by the computer, it's highly unlikely that a battery can damage the alternator, I was told years ago by a professional source that they can't.

Now, about this PCM replacement, have you ever had a bad battery, or charging system problem that some how resulted in the radio fuse getting blown during the incident? What if the reason they could not link up with the PCM was because the fuse was blown from the unit being underpowered due to the low alternator output. Not saying that's what happened, but I can see how your circumstance coupled with a technician quick to jump to conclusions could have resulted in this given my incident described above. Fuses are put in place to protect and must be checked before any component that uses them is condemned.
 

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I'm an ASE certified master technician (44 years exp) and i was browsing some forum threads for a power steering issue on my 85 year old mothers 2010 CTS 3.6L and here's the original complaint. my sister was driving the car and started noticing a whining coming from the engine then the steering got slightly stiffer and a service power steering message appeared in the DIC so she calls big bro (that's me) and i tell her that its possibly power steering pump or rack n pinon or low on fluid and she should take it to the shop and have it diagnosed as i'm 200 miles away, well the dealer is the shop my mom likes so it go's. They tell her it needs ps pump, rack and pinon, control solenoid valve, shocks, struts, 4 wheel alignment and that will be 6 THOUSAND DOLLARS! now i'm a "if it ain't broke don't fix it" kinda guy and that goes for customers and relatives alike so I say HELL NO and tell my sis im coming to get it so im in the cady and starting it up i notice it cranks a little slow but i know it hasn't been driven for several days so file that away and proceed home, about a hundred miles go by and the battery lite comes on so i cycle through the DIC to check the battery voltage 13.4 not bad not great i proceed, then with 1/4 mile to go the alternator gives up i cruise the rest of the way home and put the car and myself to bed. next day i install new alternator after work and drive it for a couple days to monitor the power steering but the whine has gone away and no messages in the DIC so it appears that the problem was a lack of voltage to the PS control solenoid do to a failing alternator which goes back to what Joseph Upson was explaining, the moral is.....Everything in today's vehicles is electronically controlled, make sure thee electricity is there.
 

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**2014 CTS4 Sport Wagon-Luxury**
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that's sad that a dealership couldn't figure out just what you figured out without adding that laundry list of "repairs and replacements"...glad you got it sorted saving a lot of money...

Bill

I'm an ASE certified master technician (44 years exp) and i was browsing some forum threads for a power steering issue on my 85 year old mothers 2010 CTS 3.6L and here's the original complaint. my sister was driving the car and started noticing a whining coming from the engine then the steering got slightly stiffer and a service power steering message appeared in the DIC so she calls big bro (that's me) and i tell her that its possibly power steering pump or rack n pinon or low on fluid and she should take it to the shop and have it diagnosed as i'm 200 miles away, well the dealer is the shop my mom likes so it go's. They tell her it needs ps pump, rack and pinon, control solenoid valve, shocks, struts, 4 wheel alignment and that will be 6 THOUSAND DOLLARS! now i'm a "if it ain't broke don't fix it" kinda guy and that goes for customers and relatives alike so I say HELL NO and tell my sis im coming to get it so im in the cady and starting it up i notice it cranks a little slow but i know it hasn't been driven for several days so file that away and proceed home, about a hundred miles go by and the battery lite comes on so i cycle through the DIC to check the battery voltage 13.4 not bad not great i proceed, then with 1/4 mile to go the alternator gives up i cruise the rest of the way home and put the car and myself to bed. next day i install new alternator after work and drive it for a couple days to monitor the power steering but the whine has gone away and no messages in the DIC so it appears that the problem was a lack of voltage to the PS control solenoid do to a failing alternator which goes back to what Joseph Upson was explaining, the moral is.....Everything in today's vehicles is electronically controlled, make sure thee electricity is there.
 

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Go ahead, blame me. Everybody does 🙄
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Welcome, tooltwister-

Sounds like an unscrupulous dealer saw an opportunity to take advantage of someone.
Good call making the trip to get the Caddy and diagnosing it yourself.
 

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Dealerships are a real problem. everyone that works there is paid Commission. So if they don't make a sale they don't make any money.
 

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Dealerships are a real problem. everyone that works there is paid Commission. So if they don't make a sale they don't make any money.
They probably would've scared her into trading it in if her son didn't get involved.
Six grand worth of unnecessary repairs solved with a $250 alternator.
 

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A few days ago my best friend took his wife's 2018 Tahoe in for oil change at chevy dealer in Newport beach.
After they got it in the shop the service writer told him that the car needed all sorts of things and the repairs would cost thousands of dollars. My friend said that fine, it is a "CPO" Cert. Pre. Owned car still under full warranty, fix all under warranty. The service writer came back 10 minutes later and said he made a mistake, it was not my friend's car that needed the repairs. My friend's car did not need any repairs.
 

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Oooops, I tried fleecing the wrong customer. My apologies.
 

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2010 CTS 3.6L and here's the original complaint. my sister was driving the car and started noticing a whining coming from the engine then the steering got slightly stiffer and a service power steering message appeared in the DIC
Exact same thing happened to me, except I was the driver and not my sister. Thought it was a power steering pump because of the service power steering message but it ended up as a bad bearing in the alternator. Was shopping around for quotes on the work and I decided to see if the dealer would offer me a decent rate, but they wanted $1700 for parts and labor, lol.
 
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