4 wire O2 Sensor Troubleshooting

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Dec 20, 2006 | 10:29 PM

simapg

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4 wire O2 Sensor Troubleshooting

I need help troubleshooting a 4 wire O2 Sensor. I did an internet search and got conflicting information:

Black wire1: Heater element neg
Black wire2: Heater element 12 VDC
Gray: High output signal (ECM)
White: Low output signal (ECM

or

Black wire1: Heater element neg
Black wire2: Heater element 12 VDC
Gray: O2 ground
White: O2 signal

Please advise, I need to know to properly troubleshoot the my O2 sensor & harness.

Dec 21, 2006 | 10:22 PM

Dryfire152

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From: Washington County, ME

I would go with the grey as the high output signal to the ECM, 02 sensors produce the referance voltage that goes to the ECM. So it would not need a ground.

Dec 22, 2006 | 09:41 AM

youngfordguy

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the first link on this page has a o2 section and how to test them

Dec 22, 2006 | 11:07 AM

simapg

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youngfordguy, thanks for the info. I scaned through the O2 troubleshooting pages, but only notice 1 wire and multi wires up to 3 wires. My bronco II is a late model 89 and the wiring harness and original O2 sensor have 4 wires vs 3 wires. That fourth wire (orange) is the wire in question. On my buddy's 89 bronco II, he only has a 3 wire harness and 3 wire O2 sensor and the orange wire coming off of the ECU harness is grounded to the vehicle body. I was planning to do the same and get a 3 wire O2 sensor.

Dec 22, 2006 | 01:56 PM

subford

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From: Easton,Ks

The fourth Orange wire is the Ground wire from pin #49 of the ECU Computer.

Dec 22, 2006 | 03:18 PM

youngfordguy

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ok ithink i got it here. the BK/LG wire is a ground. the DG/P is the wire that send info to the computer. the GY/Y is the power for the heater and and i can't find what the orange one dose

Dec 22, 2006 | 04:05 PM

subford

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From: Easton,Ks

Computer pin # 49 Orange Wire (O) HEGO GROUND
Computer pin # 29 Dark Green with P stripe (DG/P) HEGO Information
Gray with yellow stripe IGN RUN Circuit
Black with green stripe Power Ground.
Image:
http://i54.photobucket.com/albums/g9...CM/HEGOBII.gif

Last edited by subford; Dec 22, 2006 at 04:42 PM.