2006 Trailblazer SAS (Stabilitrak issue driving me crazy)

[sitedude1337]

Hi guys.

I bought a new AC Delco Steering Angle Sensor. My Stabilitrak lights come on when you turn the steering wheel. They are not on until you cut the wheel to the right at about the 3 o clock angle. Turning the steering wheel to the left does not set it off. The code goes away when you turn the car off.

Ordered a new AC delco off Amazon and its doing the exact same thing.

Hooked it up to the scanner today to monitor voltage, etc when turning the wheel.

When it hits that spot where the lights turn on I notice two things.

1. It shows 0 voltage until you move it past that point to the right then starts reading normally.

2. The sensor looks like it moves up when it hits that point and you can actually hear a creeking noise when it hits that point.

Could the new sensor be defective? Is it normal for the sensor harness to move up when turning the steering wheel?

We even reflashed the EBCM and recalibrated the yaw sensor no changes same spot those two stabilitrak lights instantly come on.

 

[m.mcmillen]

It sounds like something isn’t right with the sensor. It shouldn’t move and definitely shouldn’t be making noises.

 

[Mooseman]

I would think that two sensors with the exact same issue would be remote, especially a new one. Maybe the steering shaft bearings are worn or loose. What about the U-joint just below the sensor? If either of these have any play, it could be allowing the shaft to move around and throw off the sensor.

Is your scan tool able to pull the codes from it? That could help in the diagnosis.

 

[sitedude1337]

I would think that two sensors with the exact same issue would be remote, especially a new one. Maybe the steering shaft bearings are worn or loose. What about the U-joint just below the sensor? If either of these have any play, it could be allowing the shaft to move around and throw off the sensor.

Is your scan tool able to pull the codes from it? That could help in the diagnosis.

Thanks for your reply. The only code the throws is the c0455 for SAS. It seems like it trips that code as soon as the SAS starts to appear to move around, I can visibly see the wiring harness in front appear to bounce up when it hits that 1 spot at about 3 o clock. The stabilitrak lights do not remain on, on my envoy the service stabilitrak came on Everytime when the car was on before I changed the SAS on that vehicle.

After I get back from the store at 2pmest I'll try to grab a video of the harness moving freely when it hits that spot

 

[sitedude1337]

Here is a video of what it does

 

[Mooseman]

That is very strange indeed. Maybe check the wiring itself as that movement might have flexed and broken a wire. Try without moving the steering wheel and the light off, move the wiring itself. I'm still thinking there's something with the steering shaft making it move around like that.

 

[budwich]

in the video, is the "start position" neutral on the steering, meaning wheels straight forward? you indicate the problem is at 3o'clock on the right but has no issue at 9oclock at the left. When moving to the 9 position, does the connect moved the opposite or stays stable once "neutral" steering is reached? since you have tried two, my guess, you have either a "pin issue" in the connector or "semi-broken" wire in the connector. I would check the install of the sensor to see if the "seat" of the sensor is not broken causing the loss of "relative position".

 

[sitedude1337]

I moved the wires all around and moved the sensor back and forth without setting it off, I recorded a couple more angles of the noise and the view of what it's doing. I also got a shot of the sensor maybe you can tell if something looks broken or not in place properly?

and

 

[sitedude1337]

in the video, is the "start position" neutral on the steering, meaning wheels straight forward? you indicate the problem is at 3o'clock on the right but has no issue at 9oclock at the left. When moving to the 9 position, does the connect moved the opposite or stays stable once "neutral" steering is reached? since you have tried two, my guess, you have either a "pin issue" in the connector or "semi-broken" wire in the connector. I would check the install of the sensor to see if the "seat" of the sensor is not broken causing the loss of "relative position".

Thank you for your reply. I start at the neutral dead center and if I go all the way left the issue does not occur if I start dead slcenter and go right it happens about 3 o clock. If I start the car at about 5 o clock to the right the issue does not occur and continues as far right as the wheel goes without tripping the stabilitrak. I added two more videos of the issue a sec ago. I'm not sure how to tell if the seat is broken it seems at the connector it makes a real tight connection and moving the wires all around doesn't seem to trigger it

 

[budwich]

ok... but I also asked about what happens at the 9oclock position both in terms of the connector movement and any measurement differences. Further, what is the voltage measurement at "dead center" (neutral) on the steering? related.... monitoring the voltage while turning to the right... it starts at what value and just before going to 0, what is the voltage? And again once past the point, what voltage does it return to?

one other thing... I see there is an anti-rotation pin in the sensor which has to be removed...

 

[sitedude1337]

The connector seems to move around the same left or right I just noticed. I want to say when the light comes on the angle shows 0 then you move it past there a tad and it starts going positive I think it's like 450 angle and it triggers the light and reads 0 but at like 460 it starts reading normal and goes to positive 720 left also matches and goes to negative 720.

I did take the pin out after install read some funny posts about people forgetting to do so and it made a grinding noise turning lol.

I was in the process of reinserting the pin with the steering wheel locked to take the sensor out but I can't get the pin back in, maybe once it's removed it can't go back

Edit

The voltage I think was 4.75 or 5 I think the voltage hit 0 ,at the one spot along with a 0 angle

ok... but I also asked about what happens at the 9oclock position both in terms of the connector movement and any measurement differences. Further, what is the voltage measurement at "dead center" (neutral) on the steering? related.... monitoring the voltage while turning to the right... it starts at what value and just before going to 0, what is the voltage? And again once past the point, what voltage does it return to?

one other thing... I see there is an anti-rotation pin in the sensor which has to be removed...

I don't have the scan tool available at the moment it was my friends snap on

 

[budwich]

OK... thanks... sorry for all the questions... its both an interesting and learning problem for me... one that I hope I never have to go thru...

I am not sure I understand what you are stating with the values that you just quoted (ie. 450, 460 , 720)... are these voltages, angles? IF angles, something is funny, I think... as this appears to indicate more than one turn of the wheel... ie. 360 plus. Voltage would be nice as there is no "compute" done on them. Hopefully, you can get access to the scan tool again.

The sensor is an interesting beast and has both a digital and analog component which have to agree or there is a problem... some of which you noticed.

I am still somewhat wondering about the mounting and whether its is indeed correct or broken.

 

[sitedude1337]

Not 100 percent. The snap on tool said something like swa which I think means steering wheel angle and went -720 all the way left and +720 all the way right. I tried to get the sensor back out but that sucker seems fused now lol

 

[Mooseman]

I'm wondering if the steering shaft is bent.

 

[budwich]

if you still have the old sensor, check the anti-rotation pin "fit" on it in terms of being able to replace the pin... and then compare with the new one. It might provide a clue.

 

[sitedude1337]

if you still have the old sensor, check the anti-rotation pin "fit" on it in terms of being able to replace the pin... and then compare with the new one. It might provide a clue.

Thanks for the reply they actually covered up the hole on the stock one, not sure why.

 

[sitedude1337]

I'm still not sure if a moving sensor is normal or not I never paid attention after swapping the one in my envoy, the light went off so I never had to take it back apart lol. I'm tempted to take the envoy apart now

 

[budwich]

Thanks for the reply they actually covered up the hole on the stock one, not sure why.

ok :-( but no problem... next investigation... mark the old one so that you can put it back the way it came out for any reason to put it back on. Then move it manually and listen for any noise especially near where you indicated there was a problem (the same for both units). Still further get your meter out and do some checks on the old unit, resistance wise from the low reference to the signal pin. You can watch this measurement as you move the sensor.