chronicgs400

I have a 98 GS400 and the car will never go higher than 400 rpms at idle. Even when its cold and usually most cars idle at over 1000 then drop to normal once warm this car does not. What controls raising the rpms in this car? The throttle control motor or IAC?

I have a 98 GS400 and the dealer told me I needed to replace the IAC valve and they quoted almost $600. I want to clean it myself and see if the code goes away and it idles better. I have searched and not been able to find a DIY on this or even a single pic of the IAC valve. I have read the DIY for a rx300 but does anyone out there have a pic of the sensor for the GS400? Maybe a factory diagram of how to R&R it would work to? Any info would be great. Thanks