The 2004 Civic break peddle will not depress; power steering is going out; engine will only run if you apply the accelerator.

Check switch above brake pedal to insure it is fully depressed when pedal is up. If it is, unplug switch and if lights go off replace switch.

It is a nomral condition, in every vehicle the break paddle is hard to push before you turn the engine on. But, if you turn the engine on the paddle would go soft.

Your bake booster has failed causing a massive vaccume leak when you apply the brakes. That in turn gives more air to the system so the computer tells it to add more fuel thus causing the rpms to go up. Replace it %99.5 chance that will fix it.

First error code
P1650 - Power Steering Pressure (PSP) Switch Malfunction In Key On,
Engine Off Self-Test, this DTC indicates the PSP input to the PCM is
high. In Key On, Engine Running Self-Test, this DTC indicates that the
PSP input did not change state. Steering wheel must be turned during Key
On, Engine Running Self-Test
PSP switch/shorting bar damaged
SIG RTN circuit open
PSP circuit open or shorted to SIGRTN
PCM damaged."

P1703 - Brake Switch Out Of Self Test RangeP1780 - Transmission Control Switch Out of Self-Test Range

Sounds like you have warped rotors and or a lose caliper mounting bolt . When you stop do you feel a vibration in the brake peddle or in the steering wheel or both ? IF you feel the pulsation in the brake peddle I would suspect a brake pad / brake rotor problem . Now if you do not feel it in either and the vibration is through the whole car with out the brakes being applied i would think it may be related to and engine/drive line problem (motor mount /trans mount /axle problem)

It is a defective brake booster. When the internal diaphram of the brake booster develops cracks or pinholes from age, the crankcase vacume pulls air through the defective break booster diaphram from the air intake valve located on the rod connected to the brake peddle. At first the air leak sound my change or even go away when the brake peddle is depressed. But over time the booster diaphram will detierorieate to the point where the air leak sound will be contiuious. This is a problem that should be addressed ASAP as a defective break booster reduces the power assist to the break peddle and may make it difficult to apply enough break pressure to stop in an emergency situation.
Have the brakes checked by a certfied brake shop right away.

Your timing belt could be broken. You want to have this checked as soon as possible to prevent any further engine problems.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/david_62314e5b2470e8b5

It sounds like a prob with the cable from the peddle to the intake. Also check the motor mounts! Frankster016

Hi Dan

You did not indicate whether you checked the fluid level for your power steering. Please check this first. Please read your owners manual for specific instructions!

You may be low on fluid.

The next step would be to check your engine belt. The power steering pump is driven by a belt. It is possible that you have a loose or worn belt that is not able to turn the pump sufficiently at idle, but when you rev the engine higher, the pump produces sufficient power. One way to test this is to rev the engine, then try to turn the wheel, see if you notice any difference. Let me know.

Brian