Ben, VW Vanagon pro book says to disconnect O2 sensor with ignition off. (this resets the ECU) It says that oxygen sensor creates a pressure differential which results in a small voltage signal in the range of 175 to 1100 mV ( 0.175 V to 1.1 V) a high voltages indicates a rich mixture, a low voltage indicates a lean mixture. the oxygen sensor is electrically heated (2 white wires, ground & positive) ) to keep it at a consent operating temperature. and a signal wire for the oxygen sensor (green (sometimes black) power is supplied to the heating element when ever the ignition is ON. Oxygen sensor checking: * Engine at normal operating temperature * start engine run for 2 minutes. * remove hose from the fuel pressure regulator & plug hose * CO should increase briefly then drop in value to 0.3 to 1.1 % If NO ~ proceed to determine wether problem is with oxygen sensor or the ECU * shut off engine * disconnect Oxygen sensor **** Note**** Oxygen sensor must be disconnected with ignition off. to cancel memory in the ECU * start engine * Hold disconnection sensor wire to ground * CO content must rise If NO ~ check for continuity of wiring to ECU terminals # 2 and # 13 (this would be pin 2nd and last in top row of plug check with volt / ohm meter PINS # 1, 2 3 4 5 6 7 8 9 10 11 12 13 Bold # have pin in terminal 14 15 16 17 18 19 20 21 22 23 24 25 Italic = no pin in terminal * if continuity OK replace ECU terminal #2 & # 13 at ECU harness connector disconnected and grounded = 0 Ohms terminal #2 & # 13 at ECU harness connector connected = oo ohms Mike Boland
At 02:19 AM 5/7/2002 -0400, Ben huot wrote: >Hi guys, i receive my new Oxygen Sensor today > >but i don't see any difference with the old one!!!! > >One question: > >Many people are saying that an OS produce voltage when hot and unplug!!!! >Between 0.1 to 1 volt. (rich mixture or poor mixture)!!!!!!!!!!!!!!!!! >For now I don't agree!!! > >Should I unplug the battery to reset the ECU? > >Explanation: I get the van too normal operating temperature (OS is plug); I >unplug the OS and test voltage to this one (ground the negative and I touch >the OS sender wire with the positive of the voltmeter); I get about 450MV >(it means no reading), I never get .1 to 1 volt. If i touch the van side of >the OS wire only I get a steady .5 Volt when the OS is unplug. When i plug >back the OS (Van running and hot) it get down to 450MV or so but sometime >it give me a brief .7 volt and it goes back very fast to .350MV or no >reading!!!!!. (back and forward) I never get a steady reading; yes my >voltmeter wires are well attached. > > >What are your suggestions? > >Best regards, Ben >http://www3.sympatico.ca/huotx/engine1.htm > >Ps: I have 2 new OS sender (error from the company) and the old one, they >all give me the same reading!!! Is my $100 voltmeter faulty!!!! |
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