Ford Expedition 2000 Code P1150: Diagnosis and Fix for O2 Sensor Circuit Issues
I own a 2000 Ford Expedition and recently received a diagnostic code P1151. According to various sources, this code can indicate multiple issues, but I'm particularly concerned about potential wiring or sensor faults. The vehicle began showing signs of a leak near the A-pillar and windshield area. To prevent the battery from draining, I had to disconnect it every evening—this was due to the heater blower and radio running continuously. One day while driving, the engine suddenly died. It now only starts with difficulty, requires constant throttle adjustment to maintain idle, and lacks sufficient power for steering and braking. I've already replaced spark plugs, fuel injectors, and ignition coils. I also performed a carburetor cleaner test to check for vacuum leaks, but no issues were found. Despite these efforts, the P1151 code persists. I'm now seeking reliable guidance on how to properly diagnose and resolve this issue without further wasting money on parts. Any insight into what could be causing this code would be greatly appreciated.
Address the leak first—it may be causing electrical shorting. Use a hair drier to dry out affected wires, even if you need to separate them in the wiring harness. Then inspect the driver's side upstream oxygen sensor and its associated wiring for damage or corrosion.