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2012 CTS coupe
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Discussion Starter · #1 ·
Hey everyone!

My 2012 Cadillac CTS Coupe RWD has been having major power steering issues lately. The fan that prevents the vehicle from overheating went out along with the overheating fan at the same time. I had the fan replaced. Now the vehicle is no longer overheating but the "Service Power Steering" message still comes off and on while I am driving. When it does come on, it is hard to steer. It is not on the entire drive but it is fairly frequent. Any ideas as to what could be wrong? I bought a new power steering pump and am going to have a mechanic put it in but he told me it could be other things as well and I do not want to waste the money if that is not the cause as it does go in and out. I was also told it could be the oil center unit needing replacement because it is not transferring fluid to the power steering. Any ideas as to what this could be or how I could figure out the cause for sure prior to paying for a costly job? Perhaps others have had this issue and can advise how they fixed it?

Also note that my power steering fluid is full.

I would appreciate any assistance you can provide. Thank you!
 

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08 CTS DI
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The most common cause of loss of CTS power steering, particularly in an intermittent fashion from what I have observed here, and experienced personally is a bad alternator. Pull up the voltage on the display and observe it when the problem is present. If voltage is below 13 volts during the episode for an extended period of time the charging system needs to be checked by a capable service facility (Some unfamiliar with modern charging systems may condemn a good alternator in error). With headlights on, voltage should always be over 14 volts and specifically ~ 14.6v. When the motor is running, voltage should always be above 13v with engine running although the computer has the ability to command it much lower.

Also clarify if the problem was present before, or after the fan failure.
 

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2012 CTS coupe
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147 Posts
Discussion Starter · #3 ·
The most common cause of loss of CTS power steering, particularly in an intermittent fashion from what I have observed here, and experienced personally is a bad alternator. Pull up the voltage on the display and observe it when the problem is present. If voltage is below 13 volts during the episode for an extended period of time the charging system needs to be checked by a capable service facility (Some unfamiliar with modern charging systems may condemn a good alternator in error). With headlights on, voltage should always be over 14 volts and specifically ~ 14.6v. When the motor is running, voltage should always be above 13v with engine running although the computer has the ability to command it much lower.

Also clarify if the problem was present before, or after the fan failure.

On 14V when I started it but quickly goes in between 13V-13.5V up and down idling. Went to 14.6V and then back down to 12.5V idling.

Turned off and back on in garage. Idling at 12.4V when I started it.

13.1V-14.4 max when driving. 14.4V going 40MPH. Seems to fluctuate with how fast I am driving. It did go to 14.8V after driving for a while but eventually changed.

Seems to fluctuate a lot if I turn vehicle off/back on.

I was unable to reproduce the power steering message/problem on this drive (first time it did not happen quickly). However, I turned it off and back on and the message came on right away with the hard to turn steering. I backed out of the garage and drove. It stayed on 14.2V while driving with the problem occurring. Please keep in mind it did not come on when I was driving this time, not sure that matters.

My vehicle sounds like it is gargling every 15-20 seconds when idling. Not a normal idle. You can hear the fan kick on after a while.

The radiator fan failure went out first then the service power steering message came on.

When I was able to reproduce the message/problem just now, after seeing the voltage I turned the vehicle off and back on once again. The message was now gone, and I was able to drive without that problem.



Do you still think it is my alternator needing replacement or something else? Any advice is greatly appreciated.
 

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2012 CTS coupe
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147 Posts
Discussion Starter · #5 ·
Did you check the power steering fluid for level and foaming ?
When this occurred, power steering level was not full. I filled it up. As far as I know, there was no foaming. I also just posted the answer to Joseph's question if you see above. I posted it about the same time you replied so not sure you saw that.
 

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08 CTS DI
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It's too early to tell/guess at, at this point without some form of component testing, despite the voltage range you observed being all over the place for a 2012 in my opinion, that has the newer computer for engine management relative to the 2008-2011. Although the computer commands the output voltage of the alternator, voltage below 13v, is insufficient for the vehicle as a whole except for a brief moment

. I observed nearly exactly what you described for about a year with the alternator values (but no steering issues), where the display showed a range mostly in the mid to high 13v range, and over 14 volts with the headlights on. According to GM, the system should deliver right at 14.6v with the headlights turned on, so that is often used as a performance marker in situations like this where there is suspicion of a charging system problem. The default output setting is 13.6 volts, should the alternator be powered, without a pulse width modulation signal (like in the case of a modern alternator swapped into an older car without proper computer control).

My suspicion from the start, was that your charging system was probably experiencing a wide voltage swing, dropping low enough to trigger the power steering problem. The CTS has a low speed power assist, unlike most other domestic cars, where power steering is present as long as the parts are good and the motor is running. Strangely enough, instead of the check charging system warning in the event of an alternator problem, the check power steering warning usually crops up first, with loss of assist.

It happened to me about two months ago. The car was fine at initial startup and drive. I parked for about 35 min and immediately upon restart the power steering warning came on and there was little if any power assist. I immediately checked the voltage reading and it was flat lined in the 12 volt range as I expected, given a few weeks earlier, the voltage output stuck in that range while I was driving and didn't move until I shut the car off at a stop light and restarted it. If I had not done that, I probably would have encountered the power steering problem shortly afterwards. I had been watching it off and on for quite a while, before the alternator finally quit. In hind sight, I should have replaced it at the first sign, as I realized after the fact that had it happened to my wife she would not have been able to steer the car without considerable exertion.

You should also have the car scanned for computer and body control module (BCM) codes as BCM codes are not represented by a warning light. Have the charging system checked, some places like the most common neighborhood part stores will do it free of charge, but if they do not plug anything into the diagnostic port, chances are they are not able to test it thoroughly, by commanding specific voltage output.

A key take away from my experience, is that once my alternator was replaced, the voltage almost always sat around 14.3 volts, or higher. Initially I thought something was wrong, because the old alternator never did that, it hoovered mostly in the high 13.8 volt range, going over 14 volts when the headlights were on.

Investigate the gurgling noise if it was not present before, to make sure you do not have air in the coolant system. If the air conditioning compressor is cycling on and off, you may notice a slight stumble in engine idle from time to time. ~15 sec intervals gives me the impression it's on and cycling.

Don't throw parts at the car, I wouldn't put that steering pump on without a confirmed failure, especially given most bad power steering pumps whine. Understand that the computer has the ability to command the voltage output over a wide range, but there is a minimum effective range necessary to support the vehicle requirements and be able to charge the battery at the same time and that tends to be at, or above 14 volts more so than below that. You can find documentation on the web, by searching GM alternator duty cycle and clicking images at the top of the browser to see pictures of it.

Also keep an eye on your battery voltage at power on before the car is started, particular the first start of the day after sitting for a day, or two. If you're seeing frequent voltage in the mid to low 11 volt range, you may be due for a battery replacement also.
 

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2012 CTS coupe
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147 Posts
Discussion Starter · #7 ·
It's too early to tell/guess at, at this point without some form of component testing, despite the voltage range you observed being all over the place for a 2012 in my opinion, that has the newer computer for engine management relative to the 2008-2011. Although the computer commands the output voltage of the alternator, voltage below 13v, is insufficient for the vehicle as a whole except for a brief moment

. I observed nearly exactly what you described for about a year with the alternator values (but no steering issues), where the display showed a range mostly in the mid to high 13v range, and over 14 volts with the headlights on. According to GM, the system should deliver right at 14.6v with the headlights turned on, so that is often used as a performance marker in situations like this where there is suspicion of a charging system problem. The default output setting is 13.6 volts, should the alternator be powered, without a pulse width modulation signal (like in the case of a modern alternator swapped into an older car without proper computer control).

My suspicion from the start, was that your charging system was probably experiencing a wide voltage swing, dropping low enough to trigger the power steering problem. The CTS has a low speed power assist, unlike most other domestic cars, where power steering is present as long as the parts are good and the motor is running. Strangely enough, instead of the check charging system warning in the event of an alternator problem, the check power steering warning usually crops up first, with loss of assist.

It happened to me about two months ago. The car was fine at initial startup and drive. I parked for about 35 min and immediately upon restart the power steering warning came on and there was little if any power assist. I immediately checked the voltage reading and it was flat lined in the 12 volt range as I expected, given a few weeks earlier, the voltage output stuck in that range while I was driving and didn't move until I shut the car off at a stop light and restarted it. If I had not done that, I probably would have encountered the power steering problem shortly afterwards. I had been watching it off and on for quite a while, before the alternator finally quit. In hind sight, I should have replaced it at the first sign, as I realized after the fact that had it happened to my wife she would not have been able to steer the car without considerable exertion.

You should also have the car scanned for computer and body control module (BCM) codes as BCM codes are not represented by a warning light. Have the charging system checked, some places like the most common neighborhood part stores will do it free of charge, but if they do not plug anything into the diagnostic port, chances are they are not able to test it thoroughly, by commanding specific voltage output.

A key take away from my experience, is that once my alternator was replaced, the voltage almost always sat around 14.3 volts, or higher. Initially I thought something was wrong, because the old alternator never did that, it hoovered mostly in the high 13.8 volt range, going over 14 volts when the headlights were on.

Investigate the gurgling noise if it was not present before, to make sure you do not have air in the coolant system. If the air conditioning compressor is cycling on and off, you may notice a slight stumble in engine idle from time to time. ~15 sec intervals gives me the impression it's on and cycling.

Don't throw parts at the car, I wouldn't put that steering pump on without a confirmed failure, especially given most bad power steering pumps whine. Understand that the computer has the ability to command the voltage output over a wide range, but there is a minimum effective range necessary to support the vehicle requirements and be able to charge the battery at the same time and that tends to be at, or above 14 volts more so than below that. You can find documentation on the web, by searching GM alternator duty cycle and clicking images at the top of the browser to see pictures of it.

Also keep an eye on your battery voltage at power on before the car is started, particular the first start of the day after sitting for a day, or two. If you're seeing frequent voltage in the mid to low 11 volt range, you may be due for a battery replacement also.
Thank you for all of the information. Do I just ask the part stores to check my battery and alternator or something more specific?
 

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2009 SRX V6 RWD, 2011 CTS Premium Coupe
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Thank you for all of the information. Do I just ask the part stores to check my battery and alternator or something more specific?
I know you don't want to hear this, but you probably need to see a dealer, just not the one who screwed you over. The SRX had a "Charging System Failure" no one could figure out. Not the battery, not the alternator. One genius said to change out the ECM. Waste of my money and time.

I swallowed hard and went to the Chevy dealer. Turned out it was the positive battery cable. I did NOT give them the $400 they wanted to replace it; I had it towed home, got the cable for $75 at RockAuto, and did it myself. But a part store would never, NEVER have found the problem. Best $110 I will ever spend on that car.
 

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2012 CTS coupe
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147 Posts
Discussion Starter · #9 ·
I know you don't want to hear this, but you probably need to see a dealer, just not the one who screwed you over. The SRX had a "Charging System Failure" no one could figure out. Not the battery, not the alternator. One genius said to change out the ECM. Waste of my money and time.

I swallowed hard and went to the Chevy dealer. Turned out it was the positive battery cable. I did NOT give them the $400 they wanted to replace it; I had it towed home, got the cable for $75 at RockAuto, and did it myself. But a part store would never, NEVER have found the problem. Best $110 I will ever spend on that car.
Cadillac wants to charge $175 just for diagnostic. Any other place I could get it diagnosed?
 

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Go ahead, blame me. Everybody does 🙄
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Cadillac wants to charge $175 just for diagnostic. Any other place I could get it diagnosed?
Most national parts stores will test your battery and alternator for free.
I have this which does both; use it once and it more than pays for itself...
 

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08 CTS DI
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Thank you for all of the information. Do I just ask the part stores to check my battery and alternator or something more specific?
The most you'll get out of the general parts stores is a sufficient battery test, but as I mentioned earlier, if nothing is plugged into the diagnostic port for the test, chances are they will not be able to test the system to the extent needed. Many of the independent shops should have the necessary scan tools to do this for a better rate than the standard dealer diagnostic fee. I would have the charging system tested correctly before replacing any parts. If you can get your hands on a good used OE alternator through Car-part.com, it's something to keep in mind. They're pretty cheap on my end. What is your mileage? if you're over 6 figures you're in range for alternator problems. It can be something else, but with the voltage readings you provided, I wouldn't look any further until it is confirmed good, or bad.
 

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2011 CTS Coupe FE3, 2003 Thunderbird, Gone 2013 ATS, 02 Deville
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Charging System Test
Charging System Test
Diagnostic Instructions

Reference Information
Description and Operation


Charging System Description and Operation

Electrical Information Reference

Testing for Intermittent Conditions and Poor Connections

Circuit/System Testing
  1. Ignition ON, verify that no G13 generator or B18 battery current sensor DTCs are set that would cause a charging system concern.
  2. Ignition OFF, measure the voltage across the battery terminals. The voltage should read 12.0 V or greater at room temperature.

  3. NOTE
    Note
    Ensure vehicle accessories are OFF for the next step.

    Engine ON, increase engine speed to 2,500 RPM. Verify the battery voltage is between 12.6−15.0 V.
    • If not within specified range, replace the G13 generator.
  4. Engine ON, increase engine speed to 2,500 RPM. Turn ON all vehicle accessories. Verify the battery voltage is between 12.6–15.0 V.
    • If not within specified range, replace the G13 generator.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Generator Replacement (LFX) | Generator Replacement (LSA)
 

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2011 CTS Coupe Premium
Orlando - We take orphans
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Sorry but I like the BT-360 (and many clones) better. These do an extensive array of tests of both batteries and charging systems. Easy way to tell this kind of tester is plastic terminal clips each with a separate wire to each side of the clip.
An all metal clip cannot do the same tests.
592772
 

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Super Moderator
Go ahead, blame me. Everybody does 🙄
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Sorry but I like the BT-360 (and many clones) better. These do an extensive array of tests of both batteries and charging systems. Easy way to tell this kind of tester is plastic terminal clips each with a separate wire to each side of the clip.
An all metal clip cannot do the same tests.
View attachment 592772
No worries, Padgett.
I respect your decision and years of knowledge and experience. However, I have compared my results with commercial grade equipment and the readouts are nearly identical.
 

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2009 SRX V6 RWD, 2011 CTS Premium Coupe
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Cadillac wants to charge $175 just for diagnostic. Any other place I could get it diagnosed?
I did specify "Chevy" and $"110." The advantage of GM using Chevy powertrains in Cadillacs is that Chevy mechanics are equally expert at lower labor rates.
 

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2012 CTS coupe
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147 Posts
Discussion Starter · #16 ·
Just wanted to update here. Took it to OReilly. They said I have a bad battery. However, the guy said he was not able to check my alternator since my battery is bad. Not sure if that is true or not. Vehicle is still running fine but the intermittent power steering issue is still occurring. This leads me to think it is either the battery or the alternator or the charging system. I am thinking of taking it to Chevy for diagnostics then somewhere else to have it fixed for cheaper. Anyone have a better idea or know if I was given the wrong information?
 

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Just wanted to update here. Took it to OReilly. They said I have a bad battery. However, the guy said he was not able to check my alternator since my battery is bad. Not sure if that is true or not. Vehicle is still running fine but the intermittent power steering issue is still occurring. This leads me to think it is either the battery or the alternator or the charging system. I am thinking of taking it to Chevy for diagnostics then somewhere else to have it fixed for cheaper. Anyone have a better idea or know if I was given the wrong information?
My dying alternator would have passed all of the testing milestones in the diagnostics posted above before it quit altogether. 12.6v with everything "burning" and no time constraint is vague GM. I'm not sure about the LFX, but I imagine the alternator removal is about the same, pretty easy as alt changes go, just be sure to disconnect the neg battery cable first. I would look into having it rebuilt as a shot in the dark before doing the dealer dance if I were you, provided it has more than a 100k miles on it. If it did not resolve the problem the expense amounts to preventive maintenance.

If I had the problem, I'd sit down and look at the wiring diagram to the assist solenoid and tap into it without altering the harness itself, or just replace the solenoid and test, given solenoids frequently have intermittent failed conditions where some times they work and some times they don't. I believe there is a high probability that the alternator and solenoid are at the proverbial fork in the road. I'm not suggesting ebay as a source, but it was the next best thing since the part didn't popup on rockauto.


They have it, but it has to be searched for using the part#;

 

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2014 CTS4 Sport Wagon*Luxury 2016 CTS V-Sport Premium
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if you decide you need to take it to a dealer...find out up front if the diagnostic fee is rolled into the repair should you decide to have the repair done at that dealership while they already have hands on your vehicle...

what is the voltage read out in the Driver Information Center (DIC) with the ignition on but the car not running???...try this after the car has been sitting and not right after a drive...

depending on the age of your current battery you should get one and get a good one...that could alleviate your issues right there but hopefully you get your answers without out putting too much cash...

good luck with your car...

Bill
 

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08 CTS DI
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if you decide you need to take it to a dealer...find out up front if the diagnostic fee is rolled into the repair should you decide to have the repair done at that dealership while they already have hands on your vehicle...

what is the voltage read out in the Driver Information Center (DIC) with the ignition on but the car not running???...try this after the car has been sitting and not right after a drive...

depending on the age of your current battery you should get one and get a good one...that could alleviate your issues right there but hopefully you get your answers without out putting too much cash...

good luck with your car...

Bill
Yes, "arm" yourself before going to the dealer. The info shared here about the basic system characteristics can help you ask the right questions about what you're paying for. Since that solenoid is a pressure switch, I'd imagine the pressure can be tapped into and followed to determine the status when the event occurs when the proper diagnostic tool is being used.
 
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