Magnesteer
Instructor
Joined: Oct 2010
Posts: 240
Likes: 2
From: Yangpyeong Gyeonggi-Do
DIAGNOSIS
Problems with electronic variable-assist systems include all of the same things that can go wrong with a conventional power steering system (leaks, center wear in the steering gears, pump & hose failures, etc.), plus problems with the control electronics including the vehicle speed sensor circuit, the solenoid valve and control module. Accurate diagnosis, therefore, is essential to minimize warranty returns. Most of these systems provide diagnostic fault codes that can be accessed with a voltmeter, test light or scan tool to pinpoint the nature of the fault (if the fault is electronic rather than mechanical or hydraulic).
If power to the solenoid or control valve actuator is lost, the valve keeps the bypass circuit closed so full power assist is provided under all driving conditions. The only indication of trouble, therefore, might be a loss of road feel and/or increased steering sensitivity at highway speeds.
It’s important to remember that variable-rate power steering only reduces the amount of pressure that reaches the steering gear at higher road speeds. ********The only way it could reduce power assist at low speed would be in the unlikely event the actuator or solenoid valve failed in the open position. This could cause a noticeable reduction or loss of power assist.****************
On GM’s Magnasteer racks, loss of current to the magnetic coils would cause a loss of power assist at low speed. Coil resistance can be checked with an ohmmeter, and should read about two ohms. An infinite (open) reading indicates a bad coil (requires replacing the rack since the coils are not serviceable). Checking for shorts between both sides of the coil assembly and rack housing is also recommended.
The system does have self-diagnostic capability, but there is only one fault code: C1241 (Magnasteer circuit malfunction). The code is set if the module detects an open or a short in the coil circuit. If this code is present, the Magnasteer system is disabled and will not vary the steering effort as vehicle speed changes. The C1241 body code can be read with a Tech 2 or equivalent scan tool. The Tech 2 tool can also be used to perform a Magnasteer function test. The test varies the current to the coil so you can check for a change in steering effort when turning the steering wheel.
Replacement racks for variable-assist power steering applications are available with or without an EVO control solenoid. As long as the original EVO control solenoid is working OK, it can be removed and installed on the replacement rack to save your customer a few bucks. There’s no need to replace the whole rack if only the EVO solenoid valve is defective.
On GM Magnasteer applications, the whole rack must be replaced if the rack or control unit is defective because the Magnasteer unit is part of the rack. Handle with care because the permanent magnets inside the Magnasteer valve assembly and connector are fragile and can be easily damaged.
****************Also, I do not have a tech II to verify but what about this?
Compared to conventional power steering systems, Magnasteer gives the driver a much broader range of power assist with a smooth transition from low to high speed. What’s more, the system can be recalibrated to modify steering feel using a Tech 2 or equivalent aftermarket scan tool. There are three settings: factory, firmer and less firm. Just follow the scan tool prompts and that’s all there is to it. ****************
Has it been programmed to firmer???
Problems with electronic variable-assist systems include all of the same things that can go wrong with a conventional power steering system (leaks, center wear in the steering gears, pump & hose failures, etc.), plus problems with the control electronics including the vehicle speed sensor circuit, the solenoid valve and control module. Accurate diagnosis, therefore, is essential to minimize warranty returns. Most of these systems provide diagnostic fault codes that can be accessed with a voltmeter, test light or scan tool to pinpoint the nature of the fault (if the fault is electronic rather than mechanical or hydraulic).
If power to the solenoid or control valve actuator is lost, the valve keeps the bypass circuit closed so full power assist is provided under all driving conditions. The only indication of trouble, therefore, might be a loss of road feel and/or increased steering sensitivity at highway speeds.
It’s important to remember that variable-rate power steering only reduces the amount of pressure that reaches the steering gear at higher road speeds. ********The only way it could reduce power assist at low speed would be in the unlikely event the actuator or solenoid valve failed in the open position. This could cause a noticeable reduction or loss of power assist.****************
On GM’s Magnasteer racks, loss of current to the magnetic coils would cause a loss of power assist at low speed. Coil resistance can be checked with an ohmmeter, and should read about two ohms. An infinite (open) reading indicates a bad coil (requires replacing the rack since the coils are not serviceable). Checking for shorts between both sides of the coil assembly and rack housing is also recommended.
The system does have self-diagnostic capability, but there is only one fault code: C1241 (Magnasteer circuit malfunction). The code is set if the module detects an open or a short in the coil circuit. If this code is present, the Magnasteer system is disabled and will not vary the steering effort as vehicle speed changes. The C1241 body code can be read with a Tech 2 or equivalent scan tool. The Tech 2 tool can also be used to perform a Magnasteer function test. The test varies the current to the coil so you can check for a change in steering effort when turning the steering wheel.
Replacement racks for variable-assist power steering applications are available with or without an EVO control solenoid. As long as the original EVO control solenoid is working OK, it can be removed and installed on the replacement rack to save your customer a few bucks. There’s no need to replace the whole rack if only the EVO solenoid valve is defective.
On GM Magnasteer applications, the whole rack must be replaced if the rack or control unit is defective because the Magnasteer unit is part of the rack. Handle with care because the permanent magnets inside the Magnasteer valve assembly and connector are fragile and can be easily damaged.
****************Also, I do not have a tech II to verify but what about this?
Compared to conventional power steering systems, Magnasteer gives the driver a much broader range of power assist with a smooth transition from low to high speed. What’s more, the system can be recalibrated to modify steering feel using a Tech 2 or equivalent aftermarket scan tool. There are three settings: factory, firmer and less firm. Just follow the scan tool prompts and that’s all there is to it. ****************
Has it been programmed to firmer???
Last edited by seoulbrooks; Dec 16, 2010 at 05:53 PM.
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 1,147
Likes: 18
From: Thompsons Station Tennessee
DIAGNOSIS
Problems with electronic variable-assist systems include all of the same things that can go wrong with a conventional power steering system (leaks, center wear in the steering gears, pump & hose failures, etc.), plus problems with the control electronics including the vehicle speed sensor circuit, the solenoid valve and control module. Accurate diagnosis, therefore, is essential to minimize warranty returns. Most of these systems provide diagnostic fault codes that can be accessed with a voltmeter, test light or scan tool to pinpoint the nature of the fault (if the fault is electronic rather than mechanical or hydraulic).
If power to the solenoid or control valve actuator is lost, the valve keeps the bypass circuit closed so full power assist is provided under all driving conditions. The only indication of trouble, therefore, might be a loss of road feel and/or increased steering sensitivity at highway speeds.
It’s important to remember that variable-rate power steering only reduces the amount of pressure that reaches the steering gear at higher road speeds. ********The only way it could reduce power assist at low speed would be in the unlikely event the actuator or solenoid valve failed in the open position. This could cause a noticeable reduction or loss of power assist.****************
On GM’s Magnasteer racks, loss of current to the magnetic coils would cause a loss of power assist at low speed. Coil resistance can be checked with an ohmmeter, and should read about two ohms. An infinite (open) reading indicates a bad coil (requires replacing the rack since the coils are not serviceable). Checking for shorts between both sides of the coil assembly and rack housing is also recommended.
The system does have self-diagnostic capability, but there is only one fault code: C1241 (Magnasteer circuit malfunction). The code is set if the module detects an open or a short in the coil circuit. If this code is present, the Magnasteer system is disabled and will not vary the steering effort as vehicle speed changes. The C1241 body code can be read with a Tech 2 or equivalent scan tool. The Tech 2 tool can also be used to perform a Magnasteer function test. The test varies the current to the coil so you can check for a change in steering effort when turning the steering wheel.
Replacement racks for variable-assist power steering applications are available with or without an EVO control solenoid. As long as the original EVO control solenoid is working OK, it can be removed and installed on the replacement rack to save your customer a few bucks. There’s no need to replace the whole rack if only the EVO solenoid valve is defective.
On GM Magnasteer applications, the whole rack must be replaced if the rack or control unit is defective because the Magnasteer unit is part of the rack. Handle with care because the permanent magnets inside the Magnasteer valve assembly and connector are fragile and can be easily damaged.
****************Also, I do not have a tech II to verify but what about this?
Compared to conventional power steering systems, Magnasteer gives the driver a much broader range of power assist with a smooth transition from low to high speed. What’s more, the system can be recalibrated to modify steering feel using a Tech 2 or equivalent aftermarket scan tool. There are three settings: factory, firmer and less firm. Just follow the scan tool prompts and that’s all there is to it. ****************
Has it been programmed to firmer???
Problems with electronic variable-assist systems include all of the same things that can go wrong with a conventional power steering system (leaks, center wear in the steering gears, pump & hose failures, etc.), plus problems with the control electronics including the vehicle speed sensor circuit, the solenoid valve and control module. Accurate diagnosis, therefore, is essential to minimize warranty returns. Most of these systems provide diagnostic fault codes that can be accessed with a voltmeter, test light or scan tool to pinpoint the nature of the fault (if the fault is electronic rather than mechanical or hydraulic).
If power to the solenoid or control valve actuator is lost, the valve keeps the bypass circuit closed so full power assist is provided under all driving conditions. The only indication of trouble, therefore, might be a loss of road feel and/or increased steering sensitivity at highway speeds.
It’s important to remember that variable-rate power steering only reduces the amount of pressure that reaches the steering gear at higher road speeds. ********The only way it could reduce power assist at low speed would be in the unlikely event the actuator or solenoid valve failed in the open position. This could cause a noticeable reduction or loss of power assist.****************
On GM’s Magnasteer racks, loss of current to the magnetic coils would cause a loss of power assist at low speed. Coil resistance can be checked with an ohmmeter, and should read about two ohms. An infinite (open) reading indicates a bad coil (requires replacing the rack since the coils are not serviceable). Checking for shorts between both sides of the coil assembly and rack housing is also recommended.
The system does have self-diagnostic capability, but there is only one fault code: C1241 (Magnasteer circuit malfunction). The code is set if the module detects an open or a short in the coil circuit. If this code is present, the Magnasteer system is disabled and will not vary the steering effort as vehicle speed changes. The C1241 body code can be read with a Tech 2 or equivalent scan tool. The Tech 2 tool can also be used to perform a Magnasteer function test. The test varies the current to the coil so you can check for a change in steering effort when turning the steering wheel.
Replacement racks for variable-assist power steering applications are available with or without an EVO control solenoid. As long as the original EVO control solenoid is working OK, it can be removed and installed on the replacement rack to save your customer a few bucks. There’s no need to replace the whole rack if only the EVO solenoid valve is defective.
On GM Magnasteer applications, the whole rack must be replaced if the rack or control unit is defective because the Magnasteer unit is part of the rack. Handle with care because the permanent magnets inside the Magnasteer valve assembly and connector are fragile and can be easily damaged.
****************Also, I do not have a tech II to verify but what about this?
Compared to conventional power steering systems, Magnasteer gives the driver a much broader range of power assist with a smooth transition from low to high speed. What’s more, the system can be recalibrated to modify steering feel using a Tech 2 or equivalent aftermarket scan tool. There are three settings: factory, firmer and less firm. Just follow the scan tool prompts and that’s all there is to it. ****************
Has it been programmed to firmer???
My next step will be to check out the connectors. Thanks for your help, it is appreciated!
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 1,147
Likes: 18
From: Thompsons Station Tennessee
Well it warmed up a little today so I looked at a few things. I pulled the wire going to the rack from the EBCM. The rack wire measured 2.7 ohms and neither side showed a short to ground. I left the wire off and drove the car a bit. It drove like a truck! Put the wire back on and it was back to what I consider harder than normal steering.
So it appears that the Ebcm is sending a signal to the Magnasteer assy! The car is also shuddering when turning the wheel as in turning around in a cul de sac. It will also do it when I am parked and turn the wheel all the way in either direction. It did not do this prior to the Dealer changing the fluid!
Next step, back to the Dealer to check out the setting on the steering and a fluid change.
Thanks for all of your help!
So it appears that the Ebcm is sending a signal to the Magnasteer assy! The car is also shuddering when turning the wheel as in turning around in a cul de sac. It will also do it when I am parked and turn the wheel all the way in either direction. It did not do this prior to the Dealer changing the fluid!
Next step, back to the Dealer to check out the setting on the steering and a fluid change.
Thanks for all of your help!
Instructor
Joined: Oct 2010
Posts: 240
Likes: 2
From: Yangpyeong Gyeonggi-Do
From what I read the shutter at full steering travel both directions is normal during cold weather operations. There are a few threads on this subject and I know when the temps are low and tires very cold mine does the same. Little disturbing when it does occur. Good look with the dealer and hope you get a solution on your steering problems.
Merry Christmas!
Merry Christmas!
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 1,147
Likes: 18
From: Thompsons Station Tennessee
From what I read the shutter at full steering travel both directions is normal during cold weather operations. There are a few threads on this subject and I know when the temps are low and tires very cold mine does the same. Little disturbing when it does occur. Good look with the dealer and hope you get a solution on your steering problems.
Merry Christmas!
Merry Christmas!
I had started a new thread on this just titled Hard Steering. I went back to this thread because a couple of members asked about the setting of firmness via the Tech II. Another member had the identical problem that I have. In response to the question about the Tech II setting the firmness, another member a Mechanic said that the Dealer will not do this. Why, I do not know.
In any event, it is snowing and cold here so I will wait to take it back in to the Dealer. Are you in Korea?
