Hi everyone! I'm new to this forum and appreciate any help in advance. We recently purchased a 2005 Ford Expedition with 115,000 miles. The check engine light and charging system warning light are both illuminated. After running an OBD2 scan, the vehicle returned codes P0345, P0349, and P042
The wiring harness has been visually inspected with no visible damage or fraying. Are there specific testing procedures or tools recommended to verify the integrity of the connections beyond a visual check?
Use an ohmmeter to test resistance at the sensor — gently tug and shake the harness while monitoring readings with the sensor plugged in. Pierce the wires using a straight pin to simulate real-world conditions. Observe if voltage on the gray/red wire changes during movement. Also, use a DVOM set to 12V AC: connect black to battery negative and red to the alternator's charging terminal (large post) while the engine is running. This helps detect diode failures in the alternator or wiring. Sensor connectors are common failure points — if damaged, they can cause intermittent misfires and false codes. The Wells pigtail #626 is a reliable replacement for sensor harnesses. Search online for 'Wells pigtail #626' to find compatible parts.
I recommend starting with the wiring and electrical connections for the B2 camshaft position sensor — codes P0345 and P0349 are related to circuit faults and may be intermittent, contributing to both misfires and charging system issues. Check the wiring harness leading to sensor B2. Sensor #2 is located on the driver's side, just above the cylinder head, near the belt. Visually inspecting the wires didn't reveal any damage, but a more thorough inspection is needed. For reliable diagnostics, use an ohm meter to test resistance at the sensor — gently tug or shake the harness while monitoring readings. Also, check the gray/red wire for voltage fluctuations when manipulating the harness. Use a digital multimeter (DVOM) on the 12V AC setting: connect black to battery negative and red to the alternator's charging terminal (large post). Perform this test after engine startup. If diodes are suspect, use the DVOM to check them directly — many failures occur in the sensor connector itself. A common replacement part is the Wells pigtail #626, available separately if needed. More details: https://www.obd-codes.com/p0345. Note that P0349 is also intermittent and may trigger P0345.