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Discussion Starter #21
So it’s *not* a low tire pressure code, but a wheel speed sensor code?

Weird that I had to scan as passenger car, too! Not sure if I trust any of this information.
TPMS codes start with C0569 and go to C0775 in my Manual.
I would not trust your code reader until you can check your Manual.
In my 2011 Manual there are three codes per wheel:

1.) C0750 03: LF TPS Low Voltage
2.) C0750 29: LF TPS Too Few Pulses
3.) C0750 39: LF TPS Internal Malfunction

Then, C0755 for RF, C0760 for LR, and C0765 for RR, with same 03, 29, and 39 suffixes.

I haven’t reread the codes from the vehicle yet.
 

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Discussion Starter #22
In my 2011 Manual there are three codes per wheel:

1.) C0750 03: LF TPS Low Voltage
2.) C0750 29: LF TPS Too Few Pulses
3.) C0750 39: LF TPS Internal Malfunction

Then, C0755 for RF, C0760 for LR, and C0765 for RR, with same 03, 29, and 39 suffixes.

I haven’t reread the codes from the vehicle yet.
UPDATE: Just did another read of the codes and ... same thing. The only thing that keeps coming up (under "Passenger Car", not "MPV") that makes any sense whatsoever is the C0045 code for tire inflation (??).

But searching online for the C0045 code, I just found this thread of the Malibu forum. Apparently it's the darn hub .. delaminated Encoder Ring!

https://www.chevymalibuforum.com/threads/abs-light-service-stabilitrac-and-c0045-abs-code.86137/

Can't really tell what his arrows are pointing to in his pictures. Is it the brownish outer ring that's the "encoder"?? I don't see any discernible grooves or notches in it ...???
 

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therse are on the Traverse.

should be similar




 

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Discussion Starter #24
Oh. I see. Couldn't see the notches in his Malibu pictures.

Just watched a YouTube video (A1?) to change out the sensor on an Equinox rear wheel. I'm thinking (hoping?) that's what it is because the warning lights (Stabilitrak/ABS) come and go ... with no driveability issues (so far). But then again - this rear driver's wheel was the one where the Michelin Latitude sidewall blew out on me almost two years ago ... so maybe related ... and he hub will have to be replaced?

Wish I could actually test the sensor ... but regardless - it doesn't look like there's any easy way to replace it: The guy in the video ripped it all apart - right down to the emergency brake shoes in order to pull the sensor through the opening from the wheel side.

We'll see what the Helm manual has to say ...
 

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Wish I could actually test the sensor ... but regardless - it doesn't look like there's any easy way to replace it: The guy in the video ripped it all apart - right down to the emergency brake shoes in order to pull the sensor through the opening from the wheel side.

We'll see what the Helm manual has to say ...
You can with a volt/ohm meter, see link below.
Better to graph it if you can, I use a 25 year old MT 2400 Vantage.

 

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Discussion Starter #26 (Edited)
Wish I could actually test the sensor ... but regardless - it doesn't look like there's any easy way to replace it: The guy in the video ripped it all apart - right down to the emergency brake shoes in order to pull the sensor through the opening from the wheel side.

We'll see what the Helm manual has to say ...
You can with a volt/ohm meter, see link below.
Better to graph it if you can, I use a 25 year old MT 2400 Vantage.
Well, I *think* my sensor is “working” - because I only see the “Stabilitrak/ABS” messages sporadically. So if I do what the guy in the video did, it’d probably pass the test. And even if I could log it on my Harbor Fake code reader - that wouldn’t be definitive either.

Gonna have to tear it apart, I’m afraid - and get a set of eyes on it, too.

Too bad these sensors aren’t more easily replaceable, OR - an easy way to patch them out in software - so if your hub is still good, but the encoder or sensor is bad, you could just toggle a checkbox to say “this wheel speed sensor is disabled for now ... ignore it, and don’t post any alarms or errors related to it”.

Once again I go back to: not enough easy-to-read diagnostics and parameterization in these vehicles. Computerize everything with big screens and big price tags, but we’re not going to use any of it to help you out with repairs to your vehicle - even though we could very easily do it!

But we ARE going to continue to add more and more failure points, and even disable your vehicle when some of these “failures” occur so you can continue to come to our dealerships for expensive repairs. Thank you!
 

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Too bad these sensors aren’t more easily replaceable, OR - an easy way to patch them out in software - so if your hub is still good, but the encoder or sensor is bad, you could just toggle a checkbox to say “this wheel speed sensor is disabled for now ... ignore it, and don’t post any alarms or errors related to it”.
I agree with you in principal.
However if you have a checkbox to disable it, people would use it.
This would affect your Stabilitrak/ABS, not the best situation.
 

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I believe this is how the computer detects that all wheels are spinning at the same rate.
If one begins to log a difference in spin rate-- it means the tire is losing air or wheel slip has occured-- and it then does its ABS thing to bring the wheel back into contact with the road etc....
 

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Discussion Starter #29
I agree with you in principal.
However if you have a checkbox to disable it, people would use it.
This would affect your Stabilitrak/ABS, not the best situation.
You're right! I would use it! LOL!

But if you're disabling out a sensor on a non-drive wheel, maybe it shouldn't have any (functional) effect?

One thing I've noticed is: my vehicle is FWD. This error is on a rear wheel - which is not a drive wheel. So far, in at least of handful of "events" (both on the Interstate at 75 mph, and around town), ABS has never engaged. So maybe the action is different depending upon whether the problem is on a drive wheel or not?

BTW ... haven't seen the message or cluster icons in about a week now, so it's very unpredictable.
 

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I know I posted this before. dont recall if I did on this thread.
but the horbor freight scanners have a goof up- where the error code is wrong- it points to the wrong wheel.
A traverse member found this out when the scanner told him it was a certain wheel. he replaced part.
error still there.
Then used another scanner- and it pointed to another wheel. Part replaced. issue resolved.
I checked my HF unit- and it also had the error code wrong.
 

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Discussion Starter #31
I know I posted this before. dont recall if I did on this thread.
but the horbor freight scanners have a goof up- where the error code is wrong- it points to the wrong wheel.
A traverse member found this out when the scanner told him it was a certain wheel. he replaced part.
error still there.
Then used another scanner- and it pointed to another wheel. Part replaced. issue resolved.
I checked my HF unit- and it also had the error code wrong.
Yeah - I remember reading you mentioning that. My HF reader is pointing to the rear driver's wheel, but the code description says something about "Tire Inflation", not "speed sensor".

So, I'm kind of trusting the wheel location, but not the description - the reason being: that's the wheel that blew out at 75 mph on I-95 almost two years ago.

But I guess we'll see if it's correct or not. Maybe I'll find a damaged encoder and it'll be obvious, but the way it's sporadically failing, I'm thinking it won't be the encoder.
 

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ok, copy.
 

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Something I just thought of while reading your thread is that you mention having a blowout. Makes me wonder what condition all 4 tires are in, and if they all have roughly the same tread depth. Reason why I mention is because different tread depths = different wheel rpm at the same mph. The computer could read this difference in rpm as a wheel speed problem when in fact it could simply be that you need tires. Not saying this is it, just saying its something to look at.
 

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Discussion Starter #34 (Edited)
Something I just thought of while reading your thread is that you mention having a blowout. Makes me wonder what condition all 4 tires are in, and if they all have roughly the same tread depth. Reason why I mention is because different tread depths = different wheel rpm at the same mph. The computer could read this difference in rpm as a wheel speed problem when in fact it could simply be that you need tires. Not saying this is it, just saying its something to look at.
The tires are good. And the delta mileage between the replacement Michelin Latitude and the other three Latitudes (~30,000-34,000 miles) is only about 7,000-8,000 miles IIRC. So I’d say it’s unlikely.

I suppose I *could* rotate the tire, reprogram the TPMS and see if the same code pops up.

Probably should stop by an Auto Parts store and see if they could read the ABS code for me, too ... see if it points to the same wheel. They'll probably say "we can't read ABS codes, only standard powertrain codes".
 

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Discussion Starter #35
Probably should stop by an Auto Parts store and see if they could read the ABS code for me, too ... see if it points to the same wheel. They'll probably say "we can't read ABS codes, only standard powertrain codes".
So I did, and they did (with an Actron reader), and it’s the same code as my Harbor Fake reader (C0045), but with a different textual description: theirs says “Left Rear Wheel Speed Sensor Circuit: Signal Amplitude Minimum”
 

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Discussion Starter #36
Get this data point: I just completed a 2400 mile round trip over 6 days (almost constant driving) and did not see a single "Service Stabilitrak" message pop up!

If that rear wheel speed sensor (or the hub) is suspect, how could it rotate that many times and not throw a single code??
 

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Discussion Starter #37
Update: Still haven't replaced that Wheel Speed Sensor, but we've had two weeks of unseasonably warm weather here and the code and Stabilitrak/Traction cluster icons have not appeared even once! So, maybe these things are temperature-aggravated?

And I just re-read this thread ... and apparently I had missed "kastner03's" comment in Post #2 that he had two wheel speed sensors go bad on him - both on the front drive wheels - and one engaged the ABS and the other did not!

I had theorized later in this thread that maybe a failure on a non-drive wheel (as is the case with my FWD vehicle) would not engage the ABS, but I guess that's not true. It's random?

But what we still don't know, however, is whether a bad sensor causing no driveability issues can suddenly start causing driveability issues (by engaging the ABS). I've driven almost 8500 miles since 8/31/19 and so far - it hasn't happened. Still no driveability issues. Just the ding-dong cluster alarm/message and the Stabilitrak/Traction icons. Even had a 2400-mile trip in there that didn't produce a single cluster alarm! Weird!
 

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Bearing heat & expansion. Wheel speed sensors get corroded, and air gap in sensor changes affecting how it reads. It's on it way out rest assured. I've had speed sensors just go open and disable ABS and I've had sensor misreads and low speed stopping activate ABS. Those are the only wheel speed sensors failure/symptom that will affect ''drive-ability". I've had both front and rear sensors fail on different vehicles and brands. Sensor open in any position fails ABS will shut down. One thing for sure is salt zone kills them faster.
Yeah loss of ABS function is more drive-able than sensor fail falsely activating ABS at 5-10 mph stops. The latter will force replacement faster as I've experienced ABS falsely kicking in on dry pavement at low speed and darn near rear ending someone.
 
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Discussion Starter #39
Just completed a 3,000 mile round-trip (this time) and not a single “ding” alarm from the bad wheel speed sensor! Funny thing was ... just two days prior to leaving on the trip (and months having passed since the last alarm), the alarms appeared in the cluster with the audible “ding-ding-ding” while driving around town! I was thinking I’d be tortured the whole trip, but no ... didn’t even happen once!

So these wheel-speed sensors are really strange as to when they alarm and what effect they might have. Mine seem to only post the Stabilitrak and Traction Control alarms with no drive ability issues whatsoever, but there seems to be no rhyme or reason as to when the alarms appear.
 
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