This diagnostic trouble code (DTC) indicates that the idle air control (IAC) system in your 1996 Nissan King Cab pickup truck is causing the engine to idle at a higher RPM than expected. The IAC system is responsible for regulating the amount of air that bypasses the throttle valve in order to maintain the desired idle speed.
Troubleshooting steps:
- Inspect the IAC valve for damage or contamination.
- Check the IAC valve connector for proper connection and damage.
- Test the IAC valve by applying 12 volts to the terminals and observing the movement of the pintle.
- Check the throttle body for carbon buildup or other obstructions.
- Check the vacuum lines for leaks or damage.
If you have determined that the IAC valve or throttle body is faulty, you will need to replace it. If the problem persists, you may need to have the engine control unit (ECU) diagnosed and repaired.
Here are some additional tips for troubleshooting a code P0505:
- Ensure that the throttle cable is properly adjusted.
- Check the intake manifold for leaks.
- Check the air filter for restriction.
If you are not comfortable performing these checks, you should take your vehicle to a qualified mechanic.
