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Skyvisions, ASE Certified Technician
Category: Toyota
Satisfied Customers: 14445
Experience:  Toyota Master Diagnostic
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toyota corolla P0505 code

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My 1996 toyota corolla''s check engine light is on. I tested it and got a P0505 code wich is idle management system. Other than the CEL being on the car runs fine. Any ideas on hoe to troubleshoot? or fix


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This is a code for the idle speed control system has anyone worked on the car recently or been around the throttle body? Check the connector to the idle speed control motor. Click the download link for more info on the code.



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Customer: replied 9 years ago.
Thank you for your answer. No one has been around the engine for at least 5 months. And that was for an oil change. What if the connector is good? Can I run the car with out the connector pluged in. Will that make it easier to isolate the problem. Is there another step I can take besides the conector?

You can check the solenoid valve for an open circuit. This is only for idle up. It is a duty cycle valve. If the plug is in then the valve needs to be tested. There is an active test that can be done if you have a scan tool.


Customer: replied 9 years ago.
First: Is the Idle Speed Motor the only thing I can consider? Second: Can I do this test with my OBD or do I need a DLC3? Will using a ohmeter to read out the terminals tell me anything? Does the A/C idle up valve related in anyway?

If there is 12 volts at pin 2 on th ISC connector and the computer is attempting to make the ground then yes this is about it. If you look at the wiring diagram above the computer makes the ground to cycle the rotary valve. There is always the possibility of a loose pin fit at the computer or valve. Not all obd scan tools have active test capabilities. If there is a large enough vacuum leak that the ISC can not correct for then that would be the only other thing. If the valve is sticking it could set it also. Try cleaning it.


Customer: replied 9 years ago.
Is it possible to clean it without removing it? And if so what could I use? To check for a leak am I only interested in the hoses attached to the valve?

The best way to clean is to remove the throttle body and remove the valve from the bottom of it and clean with carb and choke cleaner. The hoses are water and vacuum on the valve. If you had a vacuum leak you would hear it hissing.


Customer: replied 9 years ago.
Thank you for your answers. My last question could the EFI relay also be the problem. And could I ohm it out to check it.

No the efi relay feeds many other things and the car would not run.


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