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Service park assist

13K views 57 replies 12 participants last post by  NorthernSRX  
#1 ·
I have a 2011 CTS Coupe, park assist has always worked in the past. Recently I noticed that the rear bumper wasn’t the same color as the rest of the car, before I bought it someone must’ve had an accident and did a pretty bad job repainting it. I brought it to get 3-staged painted and it looks great.

Now when I turn the car on and go into reverse I get the service park assist message, none of the sensors work at this point. When I clear it and drive the car, the next time I go into reverse all the sensors work fine and it’s like nothing ever happened. If the car sits for the rest of the day or overnight, I’ll get the message again when I start it up the next day.

I’ve tried everything, I’ve cleaned the sensors, I’ve pulled and reinstalled them, I’ve checked fuses. They clearly work but only intermittently, is this a paint job problem? Was the paint applied too heavily on the sensors and is that causing the problem? Anything helps!
 
#2 ·
Too thick paint can be a factor with sensor operation, but I would think if that was the cause the sensors would be inop each time. You may have a poor/damaged sensor connection at the harness or a sensor that is in the early stages of failure.

You can easily check the sensors for proper operation.
1. Get someone you trust to put the vehicle in accessory mode and shift to reverse while holding their foot on the brake. You can also block the wheels for added protection.
2. Put your ear to each sensor. When they are working, you will hear a faint, repetitive ticking noise. A quiet spot will make it easier to hear them.
 
#4 ·
Too thick paint can be a factor with sensor operation, but I would think if that was the cause the sensors would be inop each time. You may have a poor/damaged sensor connection at the harness or a sensor that is in the early stages of failure.

You can easily check the sensors for proper operation.
1. Get someone you trust to put the vehicle in accessory mode and shift to reverse while holding their foot on the brake. You can also block the wheels for added protection.
2. Put your ear to each sensor. When they are working, you will hear a faint, repetitive ticking noise. A quiet spot will make it easier to hear them.
I'll definitely do this as my first step. I'm thinking the shop might've damaged the sensors when pulling them out and maybe it isn't a paint job problem (it is a collision shop from a dealer, I can back up their paint work). Possibly a carelessness thing when removing problem and could've caused some damage. Like I mentioned, this never happened before and only after I got the car back, so who knows.

Connections are good as far as I know, but I'm not too keen on removing the bumper to get to them. I'll have to stick my hands up there and try it blind first.
 
#8 ·
Mmmm not yet I don't think. When I get home this weekend I'm going to throw it on the lift and poke around, see if there is something I missed. If there really isn't anything, there is a place near me called Randy's cadillac. Been around forever and only services cadillacs, they charge much less than the dealer and can pinpoint it for me. Hopefully I don't have to get to that point but it is quite frustrating that I have to spend money because of the collision shop's work.
 
#10 ·
I agree, but the dealer that I know the manager at is a honda/acura dealer. I only brought them the car to do body work and paint work. I'll be giving them a call sometime tomorrow to see what they are going to do for me. If the sensors need replacing, those are $150+ each and I'm not going to foot the bill on something that worked before I dropped the car off.

Just the module is almost $100 used and probably needs to be programmed to the car as well...
 
#11 ·
I have a related question. The parking assist hasn't worked since I bought the car. I asked a couple of questions in another thread (which I can't find now) and Long told me the LEDs in the back seat should all be showing red. They never have.

So I actually crawled into the back seat for the fourth time today. There ARE no LEDs in the back seat. The car has the sensors, and the software clearly thinks the system exists, it tells me every time I start the car.

What happened to my car?
 
#20 ·
These sensors can be very sensitive to the thickness of the paint that covers them. The rule of thumb is to never repaint them or even add clearcoat. They should have been removed or masked for a bumper paint shoot. As far as we know, the OP's sensors may have been repainted twice now - and that would be a definite no-no.

Sporadically working means that the system is still functioning but it "gets confused" every once in a while - probably dependent on what else is operating in the car, voltage levels, etc. Best bet is to spring for new sensors - they're cheap and easy to install. Aggravating though.
 
#24 ·
I have had my bumper paint four times since I have owned the car, by the same body shop. They always remove the bumper from the car and remove the sonar sensors.
They tell me "we tested the back-up sensors and they all work" when I pick up the car.
Since I have the BIG screen in the console I don't have any LED lights over the back window.

My backup sensor work.
 
#27 ·
A plethora of options! Did not know there was light-less park assist. In the business that is known as "de-contenting" where they reduce cost in an effort to increase profit as the model years drag on.
 
#29 ·
Yeah, it changed from year to year as GM moved to comply with the mandatory backup camera requirement for early 2014. In 2011, ultrasonic was available and the rearview camera was also available - in the rearview mirror in lower trims while cars equipped with navigation got the backup image on that screen instead. It appears that the parking assist lights were only available in 2011 models that were equipped with ultrasonic only (ie without back-up camera) - and there wouldn't have been too many of those. By 2012 MY models, the back-up camera in the rearview and ultrasonic were standard and upper (nav) trims got it on that screen. Presumably, that meant that the parking assist lights disappeared altogether by that point and they did not reappear at all in the gen 3 CTS.
 
#33 ·
the beeping and sonar must be standard on the higher trim levels because they aren't on the Luxury...my 2014 Luxury Sport Wagon only has the small camera in the rear view mirror...I did get the lines along with their guesstimates as to distance temporarily...

Bill
 
#35 ·
interesting...I don't see what you see on page 22 (I have the 2014 procure as well) but if you look near the end of that brochure on page 42 Sport Wagon Features and Options the Ultrasonic Park Assist is not offered or available for the Sport Wagon under Luxury but is for Performance and for Premium...

Bill
 
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#36 ·
You were right. I was reading about the coupe - I hadn't realized that the wagon would be different. Ultrasonic is standard on all trims of the coupe but not available on the 2014 luxury trim level of the wagon.

It is super difficult to follow Cadillac's exceptions year to year and trim level to trim level.
 
#39 ·
...and it does seem that the brochure jumps around a bit between models...I was looking around yesterday in my Sport Wagon as it's always possible, even after 5 years that I've been missing out on a feature... (y)

Bill
 
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#41 ·
I'm no expert on car ultrasound systems but when I designed medical ultrasound systems the precise sonar coupling of the transducer ("speaker and mic" technically) to oil/water in our case (to air in the case of your car) was extremely important. And we'd NEVER EVER even consider painting a transducer. Or at least add a coating or at least it differently from the manufacturer's method. It's a tuned system and I can't believe the general rule is to NEVER just paint over them unless you know precisely how to do it. And someone saying "well it worked fine for me" doesn't count! Just say'in...
 
#42 ·
You can buy the sensors prepainted so that shouldn't be an issue and any competent body shop should know better not to lay the color on unpainted units too heavily.
 
#43 ·
I agree. The OP had the bumper painted because of a previous paint job by the former owner - so it appears that the bumper's been repainted twice and with a 3 stage colour. Given that the problem cropped up after the last paint job, I strongly suspect that this is the culprit - the sensors weren't removed or masked when the bumper was painted. Definitely an error on the part of the body shop. To make matters worse, it's possible that the previous paint job's body shop did likewise.
 
#45 ·
Update: Took it back to the collision shop and they rediagnosed it for me. The car was hit in the rear before I ever had hand on it and it made the parking sensor harness brittle. When they took the bumper off to paint it must’ve damaged it enough to break the wire, but occasionally makes contact and works.
Im going to remove the bumper and splice the wire back together or buy a new harness for $40 and replace it. Only sensor 3 is causing a fault.
 
#49 ·
Someone backed into my Tahoe in my driveway and effed up two sensors and the harness. The point of connection between the sensors and harness are unprotected and break easily, especially since the harness is attached to the outside of the crash bar.
It doesn't take alot of force. My bumper only had superficial scratches on it.
 
#51 ·
It's not so much the harness as it is the branched connectors.
Here's a pic of my Tahoe harness- you can see the part where the sensors plug in is not very robust and is completely unprotected behind the bumper cover. When my truck was hit it was parked in my driveway and the person who hit it was slowly backing up.
596258
 
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#52 ·
Yeah, I am familiar with the harnesses for these but I didn't recognize them as being fragile - I guess it's age-related as well? My daughter's old SRX had sensor issues and I swapped in a set of new ones that fixed the problem. I guess it didn't matter if the problem was connector or sensor since the solution was the same.