Here's a tough one- I have a 1996 C220 with automatic transmission. Using an OBD reader to figure out a check engine light showed a P1700 code. I read through a CD manual and found that the problem could either be a faulty Switchover Valve or an out of adjustment Control Pressure Cable. The cable adjustment appeared to be fine. Thus, I replaced the switchover valve, but the Check Engine light came on again. I put the car on a lift to inspect the Vacuum Control Valve that is attached on the drivers side of the transmission. I found that the hose coming from the Switchover Valve had come loose from the Vacuum Control Valve (Modulating Pressure Valve?). I reattached the hose, erased the code, and for the first time, the OBD sensor showed no stored faults. However, about 1 month later the Check Engine light came on again, and the P1700 code appeared. My guess is that it is the Vacuum Control Valve (is this the same as the Modulating Pressure Valve). I don't think it's much sense to test the valve because it probably has gone bad, and I don't have the special equipment to test it anyway. Has anyone else run into similar problems, and if so what is the most common cause (other than the loose tubing) that causes a P1700 code on a C220?
Thanks

 

Sorry I can't help, I can only sympathize as I am getting the same reading..

I just bought a '94 C220 and had it towed 816 miles and now when I turn the car on there is the red CHECK ENGINE light and the red SRS lights are on. After I drive it for awhile the red SRS light goes out and then after a bit longer the red check engine light goes out and then there is a yellow ABS light that goes on and then the speedometer stops working. This lasts for a bit and then the check engine and SRS lights come back on (resulting in the speedometer working and the yellow ABS light going off). This process repeats. Also, when the car is in drive and I'm stopped the car shakes slightly.

The diagnostic code reading only gave me the P1700 code (I guess I expected more than one code). I've read on the internet about the upshift delay switch valve but I'm really not sure and after putting new tires, getting an oil change and everything since purchasing the car I'm a little strapped for cash.

Suggestions!?

Thanks..