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Oxygen Sensor Output 00000

R

RangerRuss

CEG'er
Joined
Jan 23, 2007
Messages
31
Location
Cypress, California
This is a new one for me. Recently did a complete tune-up on our 98 Contour 4-cylinder. Has been running well. The CEL came on again and the code indicated a malfunction of the O2S 2 - which is after the catalytic converter. I ran the scanner and found the output to be 0000. I have never seen this before. Usually the sensors get lazy and do not respond - output values changing - quickly but have never seen a flat line.

Is this common or is there something I need to know.

Thanks

Russ
 
Russ

Usually when O2s die the readout is 0. When they are functioning correctly the numbers are constantly changing. I suggest replacing your o2 or checking the connection and making sure its plugged in.
 
when did you take this reading? was it before or after the car was warmed up and in closed loop mode?


the lower, or down stream O2 sensor will read zero until the car is warmed up and the pre-cats are up to temp. so if you took the reading after the car was started and cold it would be zero.

please post the exact code also.
 
Thanks for your responses. Codes were PO136 and PO141. CEL has been on for a few days. The engine was 99 C when I took the readings for O2S 2 and got OOO. I just have never seen that before. Usually there is some number and very slow to change values when the engine speed changes.

I have a new sensor on order and should be here tomorrow. Will advise. All wires are connected.

Russ
 
[FONT=arial,verdana,helvetica,sans-serif]P0136[/FONT][FONT=arial,verdana,helvetica,sans-serif]Downstream Heated Oxygen Sensor circuit fault - Bank No. 1. [/FONT]

[FONT=arial,verdana,helvetica,sans-serif]P0141[/FONT][FONT=arial,verdana,helvetica,sans-serif]Downstream Heated Oxygen Sensor Heater circuit fault - Bank No. 1. [/FONT]

yes sounds like there is a problem with the down stream O2 sensor.
 
Today I installed a new oxygen sensor from my favorite NAPA dealer. Once the car was up to operating temperature I began to get a reading - went from .005 slowly to .010 and finally to .015 and stayed there. Went back to .010 once but then back to .015. Now heres the good part - my CEL came back on after a few test miles with the PO136 and PO141 again. I turned off the CEL drove the car and again PO136 and PO141. And yes I did clear the codes completely as the scanner indicated no trouble codes present.

Any ideas???

I also have an intermittent PO304 which is a misfire on cylinder #4. Last time #4 had a dirty spark plug so I changed all of them and problem went away. Plugs look real good and the spark plug wire tests good - about 4 ohms.

Any ideas on this one??

Russ
 
Even though you are reading 4ohms on the wires you could still be having an arc to ground. You sure the heater circuit is good on the sensor.
P0141 Bank 1 indicates that the heater circuit is failing hence the P0136. The Ecu checks once per driving cycle for heater current,and continious for voltage. Heater voltage check is done before heater curent check.
 
As usual, you all are right on target. Had the 'tour in the shop today and found some smashed wires. Apparently youngest son who usually drives this car bottomed it out on a steep driveway and the wiring to the o2 sensor runs along the crossbar.

Here's the interesting part, after redoing the wires, the P0304 went away by itself? Can anyone explain this 2 me as I can not understand it although the car is running great..

Another great day owning a Contour.

Russ
 
Sometimes when a CEL comes on it automatically makes another code come up aswell. In this case the O2 sensor misreading caused your misfire but as soon as the wires were fixed the ecu could adjust to run the car correctly.
 
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