Rear Shock Problem with my 2006 Cadillac

[Texas Jim]

I have had very few problems with my 2006 Cadillac DTS...
But now I have one.

A word of clarification...
It has the "Magnetic Ride" shocks and struts, not the regular kind of shocks and struts.

The rear shocks seem to be locked up...
In other words, you can grab the body at the rear wheel opening and you can't pick up the body at all.
And of course if you push down on the fender, it doesn't move either.
I have never had one do anything like this before...

I did get under it and looked at the shocks... they DO NOT appear to be leaking.

The ride is about like a one ton truck with 10 ply tires aired up to about 60psi.
There is no give ... up or down... in the rear of the car.
It's almost like it is on a solid axle with no springs at all.

The front has normal up and down give to it as I push down on it.

Any ideas are welcome before I put new shocks on it.

 

[DofD]

I'll assume that it doesn't matter if the car is running or not. It sounds like the fluid control passages in the rear shocks are blocked and not allowing the flow of fluid through the piston. If the fluid can't flow properly then the shock won't move. The fluid is a mixture of iron particles and oil. Electromagnets are used to change viscosity of the fluid changing the stiffness of the shock.

 

[Texas Jim]

I'll assume that it doesn't matter if the car is running or not. It sounds like the fluid control passages in the rear shocks are blocked and not allowing the flow of fluid through the piston. If the fluid can't flow properly then the shock won't move. The fluid is a mixture of iron particles and oil. Electromagnets are used to change viscosity of the fluid changing the stiffness of the shock.

Right... I agree.
But it's really odd that they would both malfunction at exactly the same time in exactly the same way...

 

[daddy]

I'll assume that it doesn't matter if the car is running or not. It sounds like the fluid control passages in the rear shocks are blocked and not allowing the flow of fluid through the piston. If the fluid can't flow properly then the shock won't move. The fluid is a mixture of iron particles and oil. Electromagnets are used to change viscosity of the fluid changing the stiffness of the shock.

Right... I agree.
But it's really odd that they would both malfunction at exactly the same time in exactly the same way...

Have you tried unplugging the battery? It's an electrical system and if the electromagnets control the viscosity, I'd try killing the "electro" portion and see what happens. Could be a bad controller or something and not the shocks at all.

 

[DofD]

Yep, if the control units for the rear shocks are malfunctioning then unplugging the battery might show something. Also if it were that there would be a fair constant drain on the battery.

 

[Texas Jim]

I'll assume that it doesn't matter if the car is running or not. It sounds like the fluid control passages in the rear shocks are blocked and not allowing the flow of fluid through the piston. If the fluid can't flow properly then the shock won't move. The fluid is a mixture of iron particles and oil. Electromagnets are used to change viscosity of the fluid changing the stiffness of the shock.

Right... I agree.
But it's really odd that they would both malfunction at exactly the same time in exactly the same way...

Have you tried unplugging the battery? It's an electrical system and if the electromagnets control the viscosity, I'd try killing the "electro" portion and see what happens. Could be a bad controller or something and not the shocks at all.

That's the next thing I was going to do.
Disconnect it and discharge all the capacitors...
The battery is under the back seat....

 

[daddy]

I'll assume that it doesn't matter if the car is running or not. It sounds like the fluid control passages in the rear shocks are blocked and not allowing the flow of fluid through the piston. If the fluid can't flow properly then the shock won't move. The fluid is a mixture of iron particles and oil. Electromagnets are used to change viscosity of the fluid changing the stiffness of the shock.

Right... I agree.
But it's really odd that they would both malfunction at exactly the same time in exactly the same way...

Have you tried unplugging the battery? It's an electrical system and if the electromagnets control the viscosity, I'd try killing the "electro" portion and see what happens. Could be a bad controller or something and not the shocks at all.

That's the next thing I was going to do.
Disconnect it and discharge all the capacitors...
The battery is under the back seat....

Wouldn't be as easy but those shocks have to plug in somewhere. Maybe if you can get them unplugged that will suffice. Might be a bit tough on the Caddy without a lift though.

 

[Texas Jim]

That's the next thing I was going to do.
Disconnect it and discharge all the capacitors...
The battery is under the back seat....

Wouldn't be as easy but those shocks have to plug in somewhere. Maybe if you can get them unplugged that will suffice. Might be a bit tough on the Caddy without a lift though.

The connectors are at the very top of the shocks and really difficult to reach.
I'll try the battery dis-connect and see that that does.

 

[DofD]

If the control modules are keeping the electromagnets energized, it might take a little while for the fluid to return to normal after the battery is disconnected.

 

[Texas Jim]

If the control modules are keeping the electromagnets energized, it might take a little while for the fluid to return to normal after the battery is disconnected.

Right... I will leave it disconnected for an hour or so... plus touching the cable ends together for several seconds to discharge all the capacitors that retain memory.
Then when I hook the battery back up, it "SHOULD" do a complete reboot of the system.
I will do that early in the morning... it is 97 degrees out there right now...