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dan

Lambda Sensor

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Hi all,

 

Last time I got my car looked at by a VW specialist, he told me he had to 'reset the Lambda sensor'. Apparently it can go into a 'get you home' mode if it detects a problem (or so he told me). I know that it sniffs the petrol gases & sends back the information to the ecu for timing.

My question is, how do you know if it needs resetting & how do you reset it? Am I right in saying that its located on the exhaust, on the passenger side, near the gearbox?

 

Any ideas??

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Probably he meant he cleared a fault code in the engine management unit.

Yes, it usually goes into "get you home mode" if it detects a fault, but the management unit usually starts the engine up assuming that all is well, and waits for something to go wrong. So in that sense a "reset" simply requires turning the ignition off and restarting the car afterwards.

The fault codes are logged for future reference, however.

If the same fault code occurs more than once, it's time to think about changing or at least checking out the appropriate sensor.

 

M.

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The o2 sensor acts like a battery. it feed V back to the ECU dependent on the gases produced. the ECU then corrects the fueling as needed. this shows as a cycle on the AF gauge.

 

Id disconnect the battery. im not aware of a reset. if it chuggs a bit and runs rich then there probly is a issue with the O2 system.

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dan, The VR6 ECU apparently has a memory and can hold fault codes or something. its been talked about alot over the years. The according to VW the probe should be changed every so many thousand miles regardless of condition (feck that at £90) or what ever the price.

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Looking at the rear engine mount, you'll see a 4 wire multiplug. That is your 02 sensor connector. Get a voltmeter with pointy probes. Get the car up to temp, with the engine running, poke the meter's red probe into the white wire (so that it penetrates the sheathing) and put the black probe to earth. The voltage should constantly fluctuate between 0.1 and 1V. If stays still at 0.5V or there abouts, the sensor is dead.

 

If the ECU receives no signal or a signal that's out of range, it'll load the emergency map which is very rich to prevent the engine pinking itself to death. The excess fuel will wash the bores and destroy the cat, so do it soon if you suspect the sensor is dead.

 

Kev

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