'07 GMC Envoy Steering Position Sensor

63vette

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#1
I have a customer with an '07 GMC Envoy 4.2L. The complaint was that the stability system light would come on intermittently. I pulled all of the codes on this vehicle. Discounting a couple of unrelated comm codes in other modules, there were two codes in the ABS module:
C0455 - Front steering position sensor circuit malfunction.
C0244 - PWM delivered torque malfunction.

After checking out both diagnostic trees, I cleared the codes and have driven the vehicle a few times while monitoring the outputs (analog & digital) of the position sensor. It has not reset the code yet but I did find that the digital output (the steering wheel angle in degrees) is off by 56 degrees. The analog signal voltage is well within the correct range.

The info for a C0455 DTC indicates that the DTC will be set if:
* The digital steering wheel position signal does not correlate with the analog steering wheel position signals.
* When driven forward in a straight line, the centered steering angle differs by more than 30 degrees from the centered steering angle when the sensors are initialized.

I assume that the digital sensor has "slipped" within the SWPS housing to cause it to indicate -56 degrees when the wheel is centered. The analog signals show a voltage of 2.44V, which is within the acceptable range of 2.3 to 2.7V.

Has anyone run into a similar problem and would replacing the SWPS correct it?

Thank you in advance...
 

kev2

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#2
not 'lucky' enough to work on the ENVOYs but the full size models - check the TSB,s and calibrations.

Is there a retained menory in the EBCM* ? - maybe try disconnect the battery for at least 60 seconds and then reconnect. This will insure a complete power-down of the EBCM. Turn Key On Ignition and operate the vehicle at speeds greater than 15 km/h (10 mph) to complete the self test. Verify no telltales or DTCs reset.

Unlikely with -56 ( off left)- steering wheel or alignment off

BUT I think it will be the SWPS

*paste and copy from a GM site...I mean GM like site
 

Gus

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#3
Normally what happens with these sensors is, they set a code, you clear it, road test it, and the code does not come back.....sometimes, you have to make quick turns, or figure 8's in a parking lot, to make it happen, but that still may not make it happen if it's intermittant.....the usual fix is, replace the sensor....

However, in this case, the data is WAY OFF......was a sensor previously installed on this vehicle incorrectly? When a new one is installed, on a scan tool, in the ABS section, there is a a procedure for resetting the new sensor.....

With the data like this, it's looking like a sensor....make sure you follow installation to the letter.....Have never done one on this vehicle.....on cars, the Park Ave's were the worse.....but on this one the intermediate shaft should easily come out to access the sensor.....then you have to use the special function of the scanner to setup the new sensor.....MAKE SURE YOU LOCK THE WHEEL STRAIGHT AHEAD.......you don't want to be replacing an SIR coil....
 

63vette

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#4
Thanks guys...as it turns out, the customer decided that he is going to trade this vehicle in for another because there are other issues that need to be addressed as well (possible trans concerns and front hub/bearing assemblies among others).

Yes, I learned my lesson years ago when replacing an intermediate steering shaft in a Silverado without locking the steering wheel and ended up having to replace the SIR coil, too.

FYI, I had cleared the codes originally and the C0455 did return soon after the first time but I didn't get it to set again after that. I have a hard time believing that alignment or the steering wheel being repositioned off-center on the shaft would account for the steering angle to be off by 56 degrees! Besides, the vehicle goes straight down the road with the wheel centered AND the analog signals generate to correct voltage. My customer would have certainly mentioned if this sensor had been replaced before and the problem didn't exist until fairly recently.

I have to think that the problem is internal to the digital output that generates the steering angle in the SWPS. Thanks again for your input...Allen
 

©hester

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#5
I have a customer with an '07 GMC Envoy 4.2L. The complaint was that the stability system light would come on intermittently. I pulled all of the codes on this vehicle. Discounting a couple of unrelated comm codes in other modules, there were two codes in the ABS module:
C0455 - Front steering position sensor circuit malfunction.
C0244 - PWM delivered torque malfunction.

After checking out both diagnostic trees, I cleared the codes and have driven the vehicle a few times while monitoring the outputs (analog & digital) of the position sensor. It has not reset the code yet but I did find that the digital output (the steering wheel angle in degrees) is off by 56 degrees. The analog signal voltage is well within the correct range.

The info for a C0455 DTC indicates that the DTC will be set if:
* The digital steering wheel position signal does not correlate with the analog steering wheel position signals.
* When driven forward in a straight line, the centered steering angle differs by more than 30 degrees from the centered steering angle when the sensors are initialized.

I assume that the digital sensor has "slipped" within the SWPS housing to cause it to indicate -56 degrees when the wheel is centered. The analog signals show a voltage of 2.44V, which is within the acceptable range of 2.3 to 2.7V.

Has anyone run into a similar problem and would replacing the SWPS correct it?

Thank you in advance...
`I have the same C0455 code in a 2007 trail blazer. Could you please send me the diagnostic tree for this code? I would like to be sure the part is bad before spending $100 I can't get back.

Thx and regards

Chester
 
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#6
iDEALLLY YOU SHOOULD START A NEW POST, i ALMOST IGNORED BECAUSE FIRST DATES....

GIVE ME SOME TIME AND i WILL GET AND POST FOR YOU.

SoRRy sticky cap key -
 

©hester

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#7
My bad. I didn't realize it was that old. The thread came up on a web search. No hurry and Merry Christmas.