I think that i may have a Magnesteer problem? I searched these threads and came up with two posts regarding this problem. One was in 2004 and the other in 2007. One had a link that does not work.

I recently purchased my 2nd C5 Z06 a 2003. The first was a 2002 and in addition to that I had a 98 that I bought new and then a 2001 that I traded the 98 in on, So I have been driving C5'5 for 12 years.

The current one is hard to steer which feel OK when running over 30 but feels stiff when parking or just driving slow. I have the manuals and everything points to the Magnesteer but the first test uses a scan tool which I do not have.

Has anyone else had this problem, and what was the fix?

Any culprits or suggestions to look at?

8-16-10 Two Dealers an independant mechanic and I still have the problem!!

Last thing was to run "pressure tests" which came out OK. Pump OK, Rack OK, no error codes. I am running out of options?

BEEN LOOKING THROUGH THE THREADS!! I found one where the guy had the same problem as I do and it appears that He had changed the pulley for more power. I don't know what size it should be or if it has been changed but it measures about 3 inches in diameter. Does anyone know what the original LS6 pulley size is?

 

So are you getting any codes using the dic?

 

The way Magnasteer is supposed to fail is to go with straight hydraulic assist just like you would get at medium speeds. This would make the steering seem stiffer at slow speeds and maybe a little to touchy at high speeds.
Variable Effort Steering System Description and Operation
The Variable Effort Steering (VES) system, or MAGNASTEER II® varies the amount of effort required to steer the vehicle as vehicle speed changes or lateral acceleration occurs. At low speeds, the system provides minimal steering effort for easy turning and parking maneuvers. At high speeds, the system provides firmer steering (road feel) and directional stability. When the system senses lateral acceleration, steering becomes firmer to reduce oversteering. The Electronic Brake Control Module (EBCM) controls a bi-directional magnetic rotary actuator located in the steering rack and pinion. The EBCM varies the steering assist by adjusting the current flow through the actuator. The actuator adjusts the amount of power steering assist to achieve a given level of effort to steer the vehicle. The VES system accomplishes this by adding or subtracting torque on the input shaft to the rack and pinion. The main component of the system is an electromagnetic actuator, which consists of a multiple-pole ring-style permanent magnet, a pole piece, and an electromagnetic coil assembly. The VES system uses the Antilock Brake System (ABS) wheel speed sensor inputs to determine vehicle speed. When the EBCM senses vehicle speed, it commands a current to the actuator that is most appropriate for each speed. The system also uses inputs such as Handwheel position, wheelbase, understeer coefficient and steering ratio to calculate lateral acceleration. The EBCM commands current from negative two amps to positive three amps to the actuator, which is polarized. At low speeds, a negative current is commanded, which assists steering. At medium speeds, no current is commanded and steering is assisted by hydraulics only. At high speeds, a positive current is commanded, which creates steering resistance. Ignition voltage and ground are provided through the EBCM. The EBCM has the ability to detect malfunctions in the actuator or the circuitry to the actuator. Any malfunctions detected will cause the system to ramp to zero amps and steering will be assisted by hydraulics only.

Based on what you posted I assume you have a copy of some or all of the diagnostic procedures for Magnasteer. Use the DIC instead of the scanner the procedure calls for. When you look for codes on the DIC do you get a C1241? If you get that code then follow the diagnostic procedure for it. However, step 2 of that procedure calls for a current measurement and the only tool that can do that is the GM Tech 2 scan tool which lets the tech see how much current is being drawn in the Magnasteer circuits. You will have to skip that test unless you know somebody with a Tech 2 or go to the dealer. The following step in the procedure is a resistance check of the VES which you can perform with a good Digital Multimeter (need at least 10 Meg Ohm input impedance to keep from loading the circuit you are testing). There are several other wiring checks in subsequent steps in the diagnostic procedure. Depending on the results of those tests you could end up replacing the steering rack or the EBCM.

Bill

 

That is a lot of info! As per the description of the correct operation, it is not working! There are no codes in the DIC. I intend to look at the only connector involved tomorrow. As I see it, a trip to the Dealer is in order. As for your observation, or description, the steering is purely hydraulic at this point.

Thanks for the response!

 

nope!

 

I am getting no codes on the DIC. I also hooked up my cheap scan tool and it also got no codes. I jacked up the front and pulled the connector to the rack and reseated it. Are there any more suggestions before I take it to a Dealer?

 

I've had and continue to have issues with the Magnasteer sub-system. I've de-mated, cleaned the connector and reinstalled with no correction to the problem. I plan on sending my EBCM to ABSfixer for repair but my Vette is my daily driver at this time and I've seen many reports that the replacement EBCM doesn't always work correctly. Don't go to the steelership for this, you'll pay major bucks and may not get the satification you want. Anyone have history with ABSfixer please chime in and provide help?

 

Recent update

I just returned from the Dealer. They were too busy to take the car in but they agreed to hook up the Scan Tool as per the troubleshooting procedure.

They found nothing! I guess that it could be a mechanical problem but the car only has 15,900 miles on it!

Any idea's?

 

It sounds like the dealer only looked to see if there were any codes rather than doing the complete diagnostic procedure. I'm afraid you are going to have to take it somewhere with a Tech 2 and the knowledge to run the complete procedure, dealer or not. Other than that you can just start throwing money at it. If you go that way I'd start with the steering rack, it's cheaper than the EBCM.

You can get the rack from Zip Products in Richmond, VA for about $200.00. I've had one in my car for over a year and 20,000 miles with no problems.

 

I would rather not throw parts at it. You are right in that they only looked for codes and there are none. The car is drivable and the problem is a non factor on the highway. I may go drive another C5 just to make sure that I am not just imagining the problem however after owning 4 other C5's, I am pretty sure that this one is not right!

 

This may sound crazy, did you install new wheels and tires, wider tires than stock?

 

No, The wheels and tires are original. I think that the original owner had the problem and alleviated it somewhat by over inflating the tires. They were inflated to 42# when I checked them. The steering does not change no matter the speed you are driving. My plan is to take it to another Dealer for diagnosis. Whatever it is, it is not setting a code and there are no leaks nor is there any noise in the steering. The car has less than 16,000 miles on it!

 

It sounds to me like the magnasteer is bad, they fault to a medium hard setting when something is wrong. Your dealer should be able to diagnosis it with a Tech 2,

 

I took it to the Dealer yesterday. They spent a little over two hours on it. The Tech II gave no indication of a problem?

The only suggestion that they offered was to change the PS fluid. There were no codes, no leaks, and no binding in the rack. I gave the OK to change the fluid based on the fact that they said they noted improvement in other cars with magnasteer problems. I will drive it awhile and see if it improves?

They put in a lighter fluid GM Pn 12345866. At least that is the number on the invoice.

ps; There is a TSB recommending this.

 

If that doesn't fix the problem I think you may have an internal problem in the steering rack where the fluid is leaking past the piston and not applying full force to the rack. Find out from the dealer if they did the pressure tests using the J 44721 special tool. If they didn't they need to.

 

I will call and see about it next week. Thanks! I just assumed that they followed the test procedures as outlined in the manual?

 

You would hope so but you never know.

 

Sorry to hi-jack the thread~

Bill, Does the early 1998 have magnasteer? if so is there a production code I can look for to see if mine is equiped with it?

Thanks,Matt

 

All C5's have magnasteer

 

Thank you! I had a feeling but it was worth the question to absolute

Thanks,Matt