1. Check Engine Light:
* OBD-II Scanner: A 1996 F-150 likely uses an OBD-I system, which is less sophisticated than OBD-II. You'll need an OBD-I scanner (or a more advanced scanner compatible with OBD-I) to retrieve the diagnostic trouble codes (DTCs). These codes will provide clues about what's causing the check engine light. Auto parts stores often have scanners you can rent or use for free.
* Common Causes (for a 1996 F-150): Without the codes, it's difficult to say for sure, but some frequent culprits include:
* Oxygen Sensor: A faulty oxygen sensor is a very common cause of a check engine light.
* Mass Airflow Sensor (MAF): Measures the amount of air entering the engine. A dirty or faulty MAF sensor can cause issues.
* Ignition System: Problems with spark plugs, wires, distributor cap, or rotor can trigger the light.
* Engine Sensors: Various other sensors (e.g., coolant temperature sensor, crankshaft position sensor) can malfunction.
* EGR Valve: Exhaust Gas Recirculation valve problems are also relatively common.
* Troubleshooting: Once you have the codes, you can research their meaning online or consult a repair manual. This will help you narrow down the potential problem.
2. New Key:
* Immobilizer System (PATS): A 1996 F-150 might or might not have a Passive Anti-Theft System (PATS). If it does, the new key needs to be programmed to the vehicle's computer. If the PATS system is malfunctioning, it could be preventing the truck from starting, but usually, this would be accompanied by other symptoms. If the key was replaced and the truck won't start after, that's a key concern to address.
* Key Programming: If you have a PATS system and the new key isn't programmed, you'll need to have it programmed by a locksmith or a Ford dealership.
Relationship (or Lack Thereof):
The check engine light and the new key are largely independent. The check engine light indicates a problem with the engine or emissions system. The new key issue is related to the vehicle's starting system and potentially its anti-theft system. It's possible that a faulty ignition system (related to the check engine light) *could* indirectly affect the ability to start the truck, but this is unlikely to be directly related to a new key.
In short: First, get the OBD-I codes from the check engine light. This will be your best guide to troubleshooting the engine problem. Second, if you are having trouble with the new key, investigate if the vehicle has a PATS system. If so, you need to have the key programmed.
