resistance values for O2 sensor

WMWNWMN · 14th June 2006, 13:38

I have a feeling that my O2 sensor is bad, and before buying a new one at $200 us, i'd like to check the thing to see if it is in fact dead. does anybody have this data on them?
thanks
Eric

unesential · 15th June 2006, 13:32

Read out the code from your DME as a failed sensor will give a check engine. this should in turn store in the DME. codes 1221, 1222, 1264 are related to O2 sensor. To test For proper operation and not a failure you would need to monitor CO in the exhaust as there is a variable output from the detector that corresponds to O2 in the exhaust.

WMWNWMN · 15th June 2006, 21:50

thanks for the DME codes... i was hopping i could get the resistance values that could be measured w/ an ohm meter.

I removed my exhaust the other week to replace the shift linkage, and did a real stupid thing... I forgot to unhook the O2 sensor when lowering the cats & muffler.

Since then my milage has been in the shitter... about 300km on one tank! the DME hasn't showed a check engine light though.

Tomba · 19th June 2006, 15:08

Try to measure pin #16 on the diagnostic plug (20 pinned) under the hood.
Its the voltage of the 02 sensor.

When your engine is hot it should vary between 0,1 - 1,0 volts.
Rev the engine a bit and it should go up to 0,8 - 1,0 volt. (Rich mixture)
When you let go the throttle it should go down to 0,1-0,2 volts (lean mixture).

If it stay's on 0,45 volts its propably damaged. It also has to respond fast enough. (Get in mind the mixture first has to pas the sensor, so its a bit time delayed).

The heating in the sensor could be damaged to. Don't know the resistance of the heating of the O2 sensor.

Try to read out the fault codes and live data (I've your capable off).

Only US cars have a check engine light as far as I know. Since you are in Germany... (The light also has to show up when you put the ignition on).

From my readings in your post I think the sensor is damaged (300km on a tank!).

Tomba

WMWNWMN · 19th June 2006, 15:39

Great, thanks for the info... I'll check it out tomorrow morning. my guess is the sensor is bad too, i'm just trying to investigate a little bit before spending $180 on a new one

Chewbacca · 20th June 2006, 12:46

Quote:

Originally Posted by Tomba

The heating in the sensor could be damaged to. Don't know the resistance of the heating of the O2 sensor.

Resistance can be measured between pin 3+4 of the sensor. Resistance should be a max of 5 ohm with "cold" heating.