o2 / Oxygen Sensor Test How-To

nathanielbrown · Dec 28, 2007

I was not able to find this thread on here so I am posting it.

Heres how you test the 4 lead Oxygen sensors that are found on our mistresses.

Tools Needed:

Vise or Vise grip
Torch
Volt Meter

Step 1
Disconnect and Remove the suspect o2 sensor using a 22mm wrench.

Step 2
Put the o2 senor in the Vise or Vise grips

Step 3
Connect the volt meter negative lead to the black wire on the o2 sensor
Connect the volt meter positive lead to the grey wire on the o2 sensor

Step 4
Set the Volt Meter to DCV 20V

Step 5
Light the torch and place the torch flame to the probe end of the o2 sensor (the perforated end) in such a way as to touch the blue flame cone tip to the probe wall.

Step 6
The volt meter should start to rise from 0 volts to approx. 1 volt within 20 seconds. This is the first test. If it passes, maintain the flame to the probe for a total of 2 minutes and make sure the voltage does not drop during that time by any significant amount. This is the second test. If it passes this test then remove the flame and the volt meter drop back to zero. This is the last test.

Step 7

If you have made this far successfully then your o2 sensor is operating correctly and does not need to be replaced unless you like wasting money. Buy a M hat, Wallet, and keychain instead and you will still have saved yourself some money.

Hope this is of use you!

Love, Peace and Chicken Grease!

Nathaniel

M5CCIE · Dec 29, 2007

Thanks for the good info. Someone should put it on a sticky.

Mx5 · Dec 29, 2007

Hey thanks, I have a SES light which my local Avanced Auto Parts / Peake reader came up with "O2 sensor fault".
Is this a DIY or should I spend the bucks at the local dealer.?
What does 4 - O2's plus labor cost?

ard · Dec 29, 2007

DEFINITELY DIY!!!! Never, ever, ever, ever pay a dealer to do O2 sensors, OK?

Now, you might consider a Peake reader to tell you which O2s are bad. But as a safe bet, just replace the pre-cat O2s on both sides.... Post cat O2s rarely go bad since they are not as challenged.

A

Racerxjling · Dec 29, 2007

+1 a DIY easy project. Need a 22mm open end wrench and a 10mm socket to remove the plastic cover where the (O2 sensor connects). Be careful not to get any of the anti seize (pre applied on Bosch sensors) on the sensor itself.

Jeff

Ottoman · Dec 30, 2007

is it possible to clean your o2 Sensors to de-foul them? or will it damage the sensor..

something like Carb cleaner or liquid wrench or wd-40 etc..

jjc1843 · Dec 30, 2007

Ottoman said:
is it possible to clean your o2 Sensors to de-foul them? or will it damage the sensor..

something like Carb cleaner or liquid wrench or wd-40 etc..

The O2 sensor degenerates over time from exposure to the exhaust. They cannot be cleaned. The sensor burns away.

zed.inc · Feb 10, 2015

General information on the 4-wire O2 sensor:

- the two white wires are for the built-in heater
- the grey wire is earth
- the black wire is the signal

If the OP's suggestion of connecting black to negative and grey to positive will give a negative voltage readout (not that it really matters for the purposes of testing with a multimeter).

I believe this DIY is good for testing for things like circuit continuity and voltage readout range, but won't be of much use to determine if the O2's have become lazy.

Sailor24 · Feb 10, 2015

Nor does it test the heaters, all that is really being tested is the lean reading which will be 1 on a failed O2 sensor. Common failure of the O2 is to report a leaner condition. Read that as the sensor will report more V than it should.

Not sure that this was being read until you brought it to the front page? Lol maybe you should have left it buried.

Racedriver777 · Feb 10, 2015

i should get this test done just to check ,i have emision fault ses light on the sensors after catalysts, but ive got told its because i have a SS exhaust on my car together with the SS cats which is known to create these bloody emisson ses lights that comes and go pretty often... some also say i need a tune to completely get rid of the SES light.

68FB · Feb 12, 2015

I have done this test on an old sensor and it worked well. Voltage shifted from 0.1 to 0.9 as the lean and rich parts of the propane flame were played on the sensor. But in the process, the thin metal shielding guarding the sensor glowed cherry red. That's over 800C. O2 sensors run about 500-600C so I would be worried about testing a good sensor, overheating it and turning it into a bad sensor.

Also as said above, it would confirm a sensor was stuck rich or lean or just dead, but it doesn't verify the switchover time used to identify if a sensor is lazy or not.

o2 / Oxygen Sensor Test How-To

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