Thread: O2 Sensor Sticks in Open Loop

I recently replaced my Front O2 sensor with the a brand new one form Rock Auto. My old one kept on throwing a code, P0130, I don't blame it it got a little wet at the convention.

Well I replaced it with a brand new 15727 (ones before that have been 15727 too). Now when city driving it is fine, but what I noticed while highway driving is that it gets stuck in Open Loop.

As soon as I start going down hill it would come back to Closed Loop. Along with it the wideband would show 13.5 A/F in open loop, while closed loop would be 14.7 to 15 cruising.

I reset my ECU, this didn't help. I rewired/crimped the O2 sensor it self, still the same problem.

Could it be the O2 sensor it self? Or ECU

Check the o2 sensor voltage during operation

Voltages seem to be normal. I'm gonna check out some other electrical items and see whats going on

Re wired the O2 sensors extender wires, compared the voltages with a DVM and tried to keep them well under .005. Reset the ECU, and still the same problem!!!

I'm calling rock auto tomorrow for replacement.

It seems like my tune is at fault on this one. I put the old tune on and it was working fine

What are you using to determine open vs. closed loop?

Dave

Using ScanGauge II along with the wideband. Once it hits open loop, the AFR's hit 13.5 etc.

Ah....OBDII