My 2002 Odyssey has an erratic idle and a P0505 trouble code

P0505 should be the IAC (Idle Air Control) System Malfunction

Hope this helps

Do you understand what exactly sets a P0505? It is not an electrical code, it is purely performance. The code sets when it can't get the idle speed within +200 / -100 of the target for more than x seconds, and it takes a failure in two successive drive cycles to set the code. ANYTHING that can cause an incorrect idle speed can set this code. Vacuum leak, dirty IAC, etc.

Error Code: P0505
Fault Location:
Idle Speed Control (ISC) System - Malfunction
Possible Cause:
-Wiring harness.
-Idle speed control (ISC) actuator/Idle air control valve (IAC) valve.
-Throttle valve tight/sticking.
-Engine control module (ECM).

Not sure I know the main concern here

What was the steering issues your working on?

The PO505 is a Generic Code -for Idle Control
System Malfunction

Don't reset the lights without getting the DTC's or diagnostic trouble codes from the car's computer. An autoparts store can hook up a diagnostic code reader for free. With the codes in hand, you can start to diagnose your issue. You can then reset the lights to see if the codes return.

The IAC is located under the throttle body.

But check the Power Steering Pressure sensor wire first. The wires are known to break at the sensor harness and cause idle problem. if it's broken then repair it first. Look from under car view.

per this address "http://www.obd-codes.com/trouble_codes/" p0505 is a "IAC (Idle Air Control) System Malfunction" it gives some good suggestions to look at to find a solution for your problem.

YOU HAVE INTAKE VACUUM LEAK AT THROTTLE BODY OR PCM HAS FAILED.NOT CONTROLLING IDLE SPEED CONTROL CIRCUIT.

is the check engine light on also? it sounds like the idle air control valve is bad. this controls the idle of the vehicle. when it is stuck open it causes too much air into the engine and causes it to rev. when it gets to a set rpm, the pcm cuts fuel. then it turns the fuel back on, then the engine revs, then it cuts fuel........code p0505 will prob be set

p0505 is directly related to the idle air control valve (sometimes called the rotary valve) i cant count how many of these i have replaced on hondas. It is located directly under the throttle body so it can be difficult to replace. I would recommend you having a professional replace this due to the difficulty of the valve removal