1991 Ford Bronco 4.9 Y, Standard, M5OD-R2FACTORY OEM SERVICE PROCEDURE

Test 32, Check For IDM Short High

Turn key off. Connect EDIS Diagnostic Cable (007-00059) to breakout box (T83L-50-EEC-IV), EDIS module and coil pack. DO NOT connect VR sensor tee. See Figure. Use EDIS No. 6 overlay. Connect EDIS diagnostic cable negative and positive leads to battery. Set EDIS diagnostic cable box switch to 4/6 CYLINDER position. Set DVOM to 20-volt scale.

Crank engine, and measure voltage between breakout box pins No. J30 (EDIS diagnostic cable IDM detector) and J7 (BAT -). If pulses are present, IDM detector output will be 5-7 volts DC. If pulses are present, go to next test. If pulses are not present, go to TEST 34.

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.