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Home >> Ford >> 1990 >> Bronco II 4WD, Standard, M5OD-R1 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Test H - Fuel Control >> Test H: Step 14 >> All Other HEGO Sensors

All Other HEGO Sensors

Connect DVOM to HEGO SIGNAL at the sensor and battery negative post.

Rerun KOER Self-Test and monitor HEGO sensor voltage. If voltage is greater than 0.5 volt, go to next step. If voltage is less than 0.5 volt, replace HEGO sensor and rerun QUICK TEST.

NOTE: Vacuum or air leaks in non-EEC-IV related areas may cause Code 41 or 91. Check the following areas: leaking vacuum actuator (A/C control motor, etc.) engine seals, EGR system, PCV system and lead contamination of HEGO sensor.
Fig 1: Checking HEGO Sensor
G90A12443
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