HOW DO I ELECTRICAL TEST LAMBDA SENSOR???

Without wishing to sound thick (I'm no electrician or physicist)...

I've just bought a cheap multi-meter and when I go to test the sensor, to get a reading, am I supposed to...


...unscrew and withdaw the sensor's head from the exhaust manifold...

...run the engine up to temp...

...with engine still running, touch the red positive probe onto the end of the sensor head...

...whilst touching the black negative probe to earth on a bare metal area of the car chassis , to create a circuit?


Am I barking up the right tree, anyone?


(BTW I know what voltages to look for, for a correctly functioning sensor)

Thanks, John

bare a tiny bit of the signal wire (i.e. remove a bit of insulaiton just big enough to get the end of yer meter lead onto it) and hold the red lead of yer meter to it (engine running and lambda still in situ) hold yer meters black lead to chassis/earth/engine metalwork
...should read 0.2-0.8v (dc setting on yer meter)

..mine only reads correctly with engine running above 1500rpm

...tape over the bared wire when your finished

Originally Posted by scoobian

bare a tiny bit of the signal wire (i.e. remove a bit of insulaiton just big enough to get the end of yer meter lead onto it) and hold the red lead of yer meter to it (engine running and lambda still in situ) hold yer meters black lead to chassis/earth/engine metalwork
...should read 0.2-0.8v (dc setting on yer meter)

..mine only reads correctly with engine running above 1500rpm

...tape over the bared wire when your finished

Cheers mate.

Sorry I forgot about this thread,,, Yeah, I've already done the test using a multimeter's +ve pin-probe to pierce the white sensor wire. Unfortunately (and as I expected), the sensor's knackered. When warmed up and engine idling, reading is stuck anywhere between 0.2 and 0.5V...

you sure?
...try revving the engine a smidgeon....like I posted: mine only shows at 1500-2k rpm+ (and thats 3 DIFFERENT sensors!!!)

Yeah but is revving the engine to c.1500-2000 revs the 'correct' thing to do when testing?!... Though thinking about it, I suppose it is - after all, it's when you're actually properly driving (various differing revs) that the Lambda sensor's doing its thang.