How do I repair p1653 SCV circuit malfunctions

The code reads as:
P1653 = SCV Circuit Malfunction / 58
An SCV is a Suction Control Valve. This is a valve that regulates fuel pressure as it reaches the injectors. If it starts to fail, the vehicle will run badly and use more fuel. The vehicle may even refuse to start.
They are not too expensive and a good mechanic will be able to change it quite quickly.

on one of the forum ages code p 1653 refers to SC V motor circuit
toyota recommended the change of both vacuum valve assembly parts T25860, -OHO30 and T25860-28070
the c person asking the question replaced the units and to date the problem was fixed
go google and type in --toyotanation.com as this is a forum page and most replies state that it is a vacuun valve assembly problem
one person had this to say the following malfunctions were experienced
VCS, VCSoff and engine check light on
the gear is alternately was stuck on overdrive --stay at the 3rd gear ( the od light not on)
the computer code reported a p1653 malfunction code
after replacing the vacuum valve assembly the symptoms went and haven't come back
any way go google and type in-- fault code p 1653 for toyota --and search pages to get a better understanding of what is wrong

Take it to a ASE certified repair facility ,they'll fix it up ! Don't just replace parts !!!!!

P0171 - is a lean code bank 1 -possible vacuum leak , low fuel pressure , plugged fuel filter ,
P0300 - is a random misfire code which is understandable with a lean code .
P0420 As the code description implies the P0420 code means that the vehicle's control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic convert needs to be replaced to fix the problem. If the P0420 code is combined with other codes, try fixing the other codes first
P0452 - EVAP Control System Pressure Sensor Low Input
P0446 - Evaporative Emission Vent System Performance
P0453 - Fuel Tank Pressure Sensor Circuit High Voltage
P1639 - PCM 5 Volt Reference Voltage Circuit Condition
P1653 - Power Steering Output Circuit Malfunction
P1651 - Fan 1 Relay Control Circuit
If you don't know what your doing take it to a repair shop before you waste your money ! You have a lot of problems here an I don't think the computer is bad , I'd say lack of maintenance ! You need to learn how to test thing's to fix them ! From the five volt reference voltage code , I'd say one of your sensors is shorted internally bring down the ref. voltage circuit causing the no start, but then again the 5volt ref. circuit in the PCM could be the problem . What you need to do is Disconnect all sensors that receive 5volt ref. signal one at a time an see if it will start . If I knew what year vehicle yours is I could tell you what sensors ! MAP, TPS , etc...

I googled: Toyota RAV4 rav4l fault code p1653scv motor circuit
This one looks like some good answers from owners:
http://www.toyotanation.com/forum/155-2nd-generation-2000-2004/161206-vsc-vsc-off-check-engine-code-p1653-2.html

Scv for toyota caldina

P1653 SCV Circuit Malfunction
This could be caused by the oil control valve, low oil level, infrequent oil changes, a fault in the wiring to the valve or a bad PCM. What is odd is that the code is not listed in my information database.

That code is manufacturer-specific and not a part of the base (3-digit) OBD-II codes that are universal.
Toyota uses P1653 to indicate VSV For ACIS Circuit Malfunction
This is the control circuit for the intake air control valve.

P1653 P1653 - Power Steering Output Circuit Malfunction Problem with electrical steering rack

1az-fse engine p1653 scv fault .how to repair