News: C5 Steering Wheel Position Sensor Replacement

[gkayvee]

For a year or so, the cruise control in my C5 convertible would disengage for no apparent reason on a flat, smooth piece of road. Initially, no trouble codes were presented. However, as time passed, the cruise would disengage more frequently, until I had to turn-off the active handling system to use the cruise at all. It then began to give warnings to service active handling and service vehicle soon. That was what I was waiting for, because the warnings would probably present trouble codes that my mechanic could actually diagnose/fix. The codes indicated that the steering wheel position sensor was failing. As described in prior posts, replacement require$ removal of the $teering column. The part is still available from The General for $110, labor was about $350.

Funny part: when the prob first started, I read a post on CAC that the cruise problem was often caused by that sensor! When I told my mechanic about it, he was reluctant to replace the sensor without codes b/c of the complexity of removing the column. No more probs since the replacement.

 

[dadaroo]

There is nothing in the FSM cruise control diagnostics or schematics that say the SWPS has any input to cruise control. That also makes sense, why should it?

I think your SWPS was having issues. However when you removed the steering column to replace it you corrected something in the cruise control circuit. You have to remove a lot of connectors that carry the circuits. Your problem may or may not come back. I hope you corrected the issue.

I would welcome anyone who can provide me a technical explanation for how the SWPS would affect cruise control. I doubt I missed any thing in the FSM.

Mr. Sam

 

[LLC5]

There is a very good chance that the cruise control issue was solved when the steering coulmn was removed, by the adjustment of the clutch and brake pedal switches on reinstallation of the column.

 

[gkayvee]

There is nothing in the FSM cruise control diagnostics or schematics that say the SWPS has any input to cruise control. That also makes sense, why should it?

I think your SWPS was having issues. However when you removed the steering column to replace it you corrected something in the cruise control circuit. You have to remove a lot of connectors that carry the circuits. Your problem may or may not come back. I hope you corrected the issue.

I would welcome anyone who can provide me a technical explanation for how the SWPS would affect cruise control. I doubt I missed any thing in the FSM.

Mr. Sam

A fault in the AHS would cause the cruise to disengage, "why wouldn't it?". The SWPS is part of the AHS and if giving a false reading to the AHS, would have disengaged the cruise. Safety feature. The pedal switches had
already been adjusted before the SWPS was replaced, that wasn't the prob. R&R of the SWPS was what solved the prob.

 

[dadaroo]

The FSM and the owners manual acknowledge that Traction Control activation will disengage cruise control. There is nothing stated to say AH will do it. I'm just trying to stick to what GM says and does not say.

Not saying you are wrong but I need a source for your position to close the books on this for me. I teach failure analysis so I am used to needing solid documentation.

Mr. Sam

 

[gkayvee]

The FSM and the owners manual acknowledge that Traction Control activation will disengage cruise control. There is nothing stated to say AH will do it. I'm just trying to stick to what GM says and does not say.

Not saying you are wrong but I need a source for your position to close the books on this for me. I teach failure analysis so I am used to needing solid documentation.

Mr. Sam

If you stick to JUST what GM says and doesn't say, isn't that your first error? AH, if engaged, WILL disengage the cruise on a C5, no doubt about it. If TC does it, why wouldn't AH do it?? It's a logical safety feature that both TC and AH would disengage the cruise--and they do. Just think about what that little brain in there is thinking: "car is skidding (AH), throttle is open on cruise, MUST shut throttle."


Maybe instead of confining your opinions and research only to the OM and FSM, a little "field research" is in order, Herr Doktor? My field research indicates without a doubt that both TC and AH will disengage the cruise. If you need my field notes as "solid documentation", they are available for $50 and free postage. BTW, is hubris spelled with one S or two, and do you teach that in failure analysis school?? :L

 

[dadaroo]

You never said that you got the Active Handling message so I still do not think your specific problem was the SWPS regardless of whether AH activation can disengage cruise control.

Nice of you to not share where you got your information.

 

[jrose7004]

I had the same problem with the last C5 that I had, a 04 coupe, and the first problem was the cruise control disengaging for no reason. It then progressed to the "Service Active Handling" message. I read the codes and replaced the steering sensor. Problem solved.

 

[gkayvee]

You never said that you got the Active Handling message so I still do not think your specific problem was the SWPS regardless of whether AH activation can disengage cruise control.

Nice of you to not share where you got your information.

Sam, reread my first post. And the response that followed your last one. In my case, replacing the SWPS solved the problem. After other potential causes were ruled-out. To suggest that replacing the SWPS was just a coincidence and didn't fix the prob isn't realistic.

If you want to validate whether or not the AHS will disengage the cruise (that's the unresolved issue here, right?) you can perform a simple driving test if you are a safe and skilled driver: get on your favorite stretch of interstate highway. Find an old-time cloverleaf interchange or exit ramp with a tight curve to it, at low-traffic time of day. Set your cruise at 50, enter the exit, and wait for the g-forces to activiate the AHS and disengage the cruise. It will disengage the cruise just after the apex of the curve. Sam, this is me sharing my source.

Drive careful ya'll!!

 

[dadaroo]

There is enough evidence to show that a SWPS issue can cause a Cruise issue.

I am trying to figure out how it does it.

I know at least one reason why TC will do it. The EBCM will generate a torque reduction request to the PCM commanding less power which disengages cruise. (This is in GM documentation)

I also know that if the torque reduction is not enough the EBCM can activate the brakes. I can't confirm that it would send a message causing a cruise disengagement to "back up" what should have already occurred.


With regard to AH, there is no mention of any torque reduction message, only braking. There is no mention of any interaction with cruise. At this point I must assume two things are at play.

• With AH engaged, any fault in the cruise control system will disengage cruise, or at least SWPS isssues
• With AH engaged and it activates providing a braking action, cruise is disengaged.

I don't think there is a torque reduction involved in AH activation but I would like to know.


I think I will see if I can use the Tech 2 to do some snapshots and review the data to see what goes on. I don't drive my car in the rain but I have friends who do. We'll find a place that we can do some testing.

 

[gkayvee]

There is enough evidence to show that a SWPS issue can cause a Cruise issue.

I am trying to figure out how it does it.

I know at least one reason why TC will do it. The EBCM will generate a torque reduction request to the PCM commanding less power which disengages cruise. (This is in GM documentation)

I also know that if the torque reduction is not enough the EBCM can activate the brakes. I can't confirm that it would send a message causing a cruise disengagement to "back up" what should have already occurred.


With regard to AH, there is no mention of any torque reduction message, only braking. There is no mention of any interaction with cruise. At this point I must assume two things are at play.

• With AH engaged, any fault in the cruise control system will disengage cruise, or at least SWPS isssues
• With AH engaged and it activates providing a braking action, cruise is disengaged.

I don't think there is a torque reduction involved in AH activation but I would like to know.


I think I will see if I can use the Tech 2 to do some snapshots and review the data to see what goes on. I don't drive my car in the rain but I have friends who do. We'll find a place that we can do some testing.

Do you suppose plugging in a code reader would reveal anything in the test scenario I mentioned?

 

[dadaroo]

Yes, it should. The Tech 2 can monitor things like if the torque reduction signal occurs.