* Low Battery Voltage/Alternator Problems: A weak battery or failing alternator can cause erratic behavior across various systems. Low voltage can lead to the ETC system going into failsafe mode (to prevent unintended acceleration) and might also confuse the parking brake system's sensors. This is a very common starting point for troubleshooting.
* Faulty PCM (Powertrain Control Module): The PCM is the "brain" of the engine and transmission. A malfunctioning PCM can affect throttle control and also misinterpret signals from other modules, including the one responsible for the parking brake system.
* Faulty Body Control Module (BCM): The BCM manages various body functions, including the parking brake system. A problem here could trigger the parking brake warning light, and if it impacts communication with the PCM, the ETC could also be affected.
* Wiring Harness Issues: Damaged, corroded, or loose wiring, particularly around the battery, PCM, or BCM, could disrupt communication between various modules, triggering both warning lights. This could also include issues with ground wires.
* Brake System Sensor Problems (Less Likely): While less likely to cause both lights simultaneously, a malfunctioning brake system sensor, especially one that interacts with the anti-lock braking system (ABS), could indirectly trigger issues. However, this would typically be accompanied by other brake-related warning lights.
* Faulty ETC Sensor/Actuator: Problems directly within the electronic throttle control system itself are possible, but less likely given that it's paired with the parking brake light.
Troubleshooting Steps:
1. Check the Battery Voltage: This should be the very first step. Use a voltmeter to check the voltage both with the engine off and running. Low voltage under load (engine running) points to an alternator problem.
2. Have the Codes Scanned: A professional mechanic or using an OBD-II scanner will read diagnostic trouble codes (DTCs) stored by the car's computer. These codes provide crucial clues to the problem's source.
3. Visual Inspection: Inspect the battery terminals, wiring harness connections, and fuses for any signs of corrosion, damage, or loose connections.
Important Note: Driving with the ETC failsafe mode active is highly discouraged, as it limits engine performance and can be unsafe. Get your Lincoln LS to a qualified mechanic as soon as possible for diagnosis and repair. Ignoring this issue could lead to more significant problems.
