Test 33, Check For IDM Open Circuit
WARNING: This page does not describe the selected car, but rather 11 other vehicles, including the 1991 Ford Ranger, 1991 Ford RV Cutaway, 1991 Ford Pickup, 1991 Ford F-Super Duty, and 1991 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
With key off and ECA disconnected, disconnect EDIS module from EDIS module tee. Leave EDIS diagnostic cable connected to vehicle harness connector. Set DVOM to 200-ohm scale. Measure resistance between breakout box pin No. J41 (IDM E) and vehicle harness connector pin No. 4. See Figure and Fig 1.
If resistance is less than 5 ohms, replace ECA. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If resistance is greater than 5 ohms, repair open circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.