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        General >> Give/Need advice to/from others >> HO2S and idle
        
(Message started by: Kjetil S on May 11^th, 2007, 1:13pm)

Title: HO2S and idle
Post by Kjetil S on May 11^th, 2007, 1:13pm

Hello,

Should I notice a difference in the idle on a 2.0 16v if I disconnect the upstream HO2S sensor?
I disconnected the plug on mine and couldn't tell the difference.

I tried getting a reading from the sensor with a multi meter, but I'm not 100% sure if I checked the correct wires. It seemed to flatline at around 0v. (Could someone confirm which two wires are signal/ground?)

Thanks

Kjetil

Title: Re: HO2S and idle
Post by scorpio_man on May 11^th, 2007, 1:22pm

hi there

black and grey (i think). the 2 white are for the heater.

hth

Title: Re: HO2S and idle
Post by Kjetil S on May 11^th, 2007, 1:23pm

Thanks. I'll go outside again and check :)

Title: Re: HO2S and idle
Post by Kjetil S on May 11^th, 2007, 1:29pm

Yep, those were correct. It fluctuates between 0.0 and 0.45 approx when I rev it. Steady 0.01 when idle.

Edit:

I see the main page says this about the HO2S system:

Quote:

A sensor should read high (0.6 to 0.9 volts) or low (0.1 to 0.4 volts.) It should never read 0.0 volts.

A Front sensor HO2S11, 21, should be showing a regular 'switch' from high to low, at a frequency of about .7 seconds. Periods of 'flatlining' ie no switching, means that the sensor may be deteriorating and may need to be changed if DTCs are being generated.

Mine seems to switch, but only between zero and low, not between low and high.

Title: Re: HO2S and idle
Post by martin_rowe on May 11^th, 2007, 1:55pm

a 1v sensor should oscilate either side of the 0.5v centre line, low output voltage indecates weak mixture / air / vacuum leak. measure with engine at 'steady' speeds, eg idle or holding at 3k.