02 sensor voltage low

Tun · 15-10-15, 12:51 PM

00525 (P0131) O2 sensor voltage low. Always had this code since I've owned the car. I recently changed the O2 (lambda) sensor while mucking about with the exhaust so was surprised for the fault code to come back after being erased. Any suggestions to what to try next? What readings should I be getting from the three wires that connect the sensor?

John. · 15-10-15, 03:24 PM

Been a while since I've manually checked, but a feed, earth, and signal would sound about right. Signal should fluctuate between 0 and 1 volt.

4v6 · 15-10-15, 06:01 PM

Id be looking for a connection issue especially since the sensors recent, probably a corroded or dirty contact on the multiplug etc.

John. · 15-10-15, 07:31 PM

Quote:

Originally Posted by 4v6

Id be looking for a connection issue especially since the sensors recent, probably a corroded or dirty contact on the multiplug etc.

There's a few earth wires bolted on around the top end of the engine...maybe worth cleaning some of these?

Tun · 22-10-15, 07:25 AM

Dodgy sensor! No continuous circuit on feed and earth and only reading 41 mv on signal. Replaced sensor with a more expensive NGK/NTK one and hey presto codes cleared. Thanks for the help chaps

22-10-15, 07:25 AM	#5
Tun Grown up member Classic Audi Club Member Join Date: May 2011 Location: Buxton Posts: 745	Dodgy sensor! No continuous circuit on feed and earth and only reading 41 mv on signal. Replaced sensor with a more expensive NGK/NTK one and hey presto codes cleared. Thanks for the help chaps __________________ 1988 MB quattro 2012 S4 Avant

15-10-15, 03:24 PM	#2
John. 4 ring whore! Classic Audi Club Member Join Date: Mar 2011 Location: Scottish Borders. Posts: 7,520	Been a while since I've manually checked, but a feed, earth, and signal would sound about right. Signal should fluctuate between 0 and 1 volt.

15-10-15, 06:01 PM	#3
4v6 Ex Member Classic Audi Club Member Join Date: Dec 2007 Posts: 5,565	Id be looking for a connection issue especially since the sensors recent, probably a corroded or dirty contact on the multiplug etc.