O2 sensor weirdness and PP2000

All your other probs if any.
Zash
Posts: 9
Joined: Sat Oct 01, 2011 10:23 pm

O2 sensor weirdness and PP2000

Post by Zash »

Hi guys,

As you might know from my previous post, I was getting CAT emissions fault. I plugged in PP2000 over OBD2 and looked at the O2 sensor measurements in under the engine ECU.

Indeed the Downstream sensor was showing 0v.

Aha! I thought.

To confirm, I measured the voltage on the gray wire vs black (earth) and it was fluctuating between 0.2v and 0.9v just as it should. WTH? PP2000 showing 0v but physical measurement showing normal voltages?!

I also wondered why the engine management light wasn't showing a fault code for the downstream sensor (only a vague and intermittent emissions fault was ever triggered).



So, as an experiment, to ensure that it was the sensor that was at fault and not the wiring or the ECU, swapped the connectors (paired the blue to green and green to blue).

Guess what? More strangeness: The upstream sensor still shows as working and the downstream sensor still shows as not working!

Am I correct in assuming that the sensors are both fine, and it seems to be a fault with wires/ECU connection of the downstream sensor?

More info:
When the sensors are swapped around or both are disconnected, I get a fault "permanent fault: Oxygen sensor heating control", but never when they are connected correctly.

Does anyone have a scooby about what the hell might be going on here?

Thanks!

[url]https://ibb.c*o/goPXDk[/url]

(Please remove * between c and o!)
Last edited by Zash on Wed Sep 20, 2017 1:47 am, edited 1 time in total.

IanL
Posts: 1526
Joined: Wed May 13, 2015 10:34 pm
Location: Jersey, Channel Islands

Re: O2 sensor weirdness and PP2000

Post by IanL »

Zash wrote: Am I correct in assuming that the sensors are both fine, and it seems to be a fault with wires/ECU connection of the downstream sensor?
That would be my conclusion.