A 2001 Ford F-550 exhibited intermittent stalling, particularly when cresting hills and letting off the gas. A new crankshaft position sensor (CPS) did not resolve the issue. After driving 2,500 miles with the problem, other electrical issues emerged, such as malfunctioning windows and a radio changing stations on its own. Eventually, the truck stalled and would not restart, even after being towed home.
An OBD2 scan tool (Amazon Link) was purchased to diagnose the problem. Upon connecting the scanner, clicking sounds were heard, the wipers activated intermittently, and the scanner screen went blank before displaying any codes. Subsequent attempts to connect the scanner were unsuccessful. Furthermore, the truck would no longer crank, despite having a good battery. The scanner appeared to exacerbate the existing electrical problems.
The suspected causes are a faulty ECM or a damaged wiring harness. A logical troubleshooting approach involves replacing the wiring harness first, followed by the ECM if the problem persists.
A failing ECM can cause various electrical problems, including stalling, no-start conditions, and erratic behavior of other components. Damaged wiring harnesses can similarly disrupt communication between modules and lead to similar symptoms. Replacing the wiring harness first addresses the potentially simpler and less expensive issue. If that doesn’t solve the problem, replacing the ECM is the next logical step. Professional mechanical assistance may be necessary if these steps fail to resolve the issue.
