1. Basic Checks:
* Check the IAC Motor: The IAC motor is a small valve usually located on the throttle body. Visually inspect it for any obvious damage (broken wires, loose connections, physical damage).
* Clean the Throttle Body: A dirty throttle body can cause inaccurate readings and contribute to idle problems. Use throttle body cleaner (specifically designed for this purpose) and carefully clean the throttle plate and surrounding area. Make sure the engine is OFF and the battery is disconnected before doing this. After cleaning, reconnect the battery and let the PCM relearn the idle.
* Check Vacuum Lines: Inspect all vacuum lines connected to the throttle body and IAC motor for cracks, leaks, or loose connections. Repair or replace any damaged lines.
* Check the Battery: A weak battery can cause erratic readings and affect the idle. Test the battery voltage.
* Check the Air Filter: A clogged air filter restricts airflow and can cause the engine to compensate by raising the idle speed. Replace if dirty.
2. More Advanced Troubleshooting:
* IAC Motor Testing: While you can't directly test the IAC motor's internal workings without specialized equipment, you can try this simple check:
* With the engine running: Carefully disconnect the IAC motor electrical connector. If the idle drops significantly (or stalls), it suggests the IAC motor is contributing to the high idle. If the idle remains high or changes little, the IAC motor may not be the primary culprit. Reconnect the connector.
* PCM Issues: In rare cases, a faulty PCM can cause this code. This is usually a last resort diagnosis and requires professional testing with a scan tool.
* Throttle Position Sensor (TPS): A faulty TPS can send incorrect signals to the PCM, leading to an incorrect idle adjustment. This usually throws a separate code, but it's worth checking the TPS voltage with a multimeter (consult a repair manual for specifications).
* Mass Airflow Sensor (MAF): A dirty or faulty MAF sensor can also cause idle problems. Clean the MAF sensor with a MAF sensor cleaner (be gentle; do not touch the sensor element) or replace it if necessary.
3. Replacement:
* Replace the IAC Motor: If the above checks point to a faulty IAC motor, replacing it is often the solution. Ensure you get a replacement IAC motor that's compatible with your 1997 Windstar 3.8L engine.
Important Considerations:
* Repair Manual: A repair manual specific to your 1997 Ford Windstar 3.8L is invaluable. It provides detailed diagrams, specifications, and troubleshooting steps.
* Professional Diagnosis: If you're uncomfortable performing these checks or the problem persists after trying these steps, take your vehicle to a qualified mechanic for professional diagnosis and repair. They have the tools and expertise to pinpoint the issue accurately.
The P1506 code is often related to the IAC motor or a related component. By systematically checking the items listed above, you should be able to diagnose and fix the problem. Remember safety first – always disconnect the battery before working on electrical components.
