Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSFORD1994F 150 4WD PICKUP V8-351 5.8LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSTESTING AND INSPECTIONPINPOINT TESTSX - CONSTANT CONTROL RELAY MODULE (CCRM)X87 - CHECK HO2S CIRCUIT FOR SHORT TO POWER
1994 Ford F 150 4WD Pickup V8-351 5.8L
X87 - Check HO2S Circuit For Short to Power
1994 Ford F 150 4WD Pickup V8-351 5.8LSECTION X87 - Check HO2S Circuit For Short to Power
- Key "OFF".
- Left or Front Heated Oxygen Sensor (HO2S) disconnected.
- Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary. Leave PCM disconnected.
- Key "ON".
Oxygen Sensor Connector:
- Measure voltage between the HO2S signal at the HO2S vehicle harness connector and chassis ground.
- Is voltage less than 1.0 volt?
Yes -- Replace PCM. Reconnect HO2S. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)
No -- Service short circuit. Reconnect PCM and HO2S. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.