Downstream talk to ECU or only Up
Downstream talk to ECU or only Up
Does anyone know for fact whether the downstream O2 sensors send info to the ECU? Or; only upstream communicate with ECU? I am replacing all 4- however if the downstream do not communicate then it would be pointless to change them? I’ve already checked the FSM in the EC section. It seems to show all 4 to the ECU- ?
Re: Downstream talk to ECU or only Up
Yeah, all 4. If it has a corresponding check engine light trouble code, then it communicates to the ECU.
What you're probably thinking about is the secondary catalytic converters (after the downstream O2 sensors) since they're unmonitored.
What you're probably thinking about is the secondary catalytic converters (after the downstream O2 sensors) since they're unmonitored.
Re: Downstream talk to ECU or only Up
Thank you Ed- yes the secondary cats are what I was thinking of.. I’ve ordered off Amazon and am a bit concerned. A G35 owner states they are incorrect on Amazon as fit. He says upstream Nissan uses 6 prong Blue, and 4 prong green downstream.. I’ve got the 4 prong green and a 4 prong Blue. I assume I’ll definitely figure it out when I get under it- I’m hopeful the 6 prong is G35 specific with the VQ series motor.
Re: Downstream talk to ECU or only Up
The FSM shows a 4-pin upstream sensor. For color, just peek in your engine bay and they should be right behind your heads. Actually, you could easily unplug the harness there too to confirm the number of pins.
Are you having issues or you just want to replace them?
Are you having issues or you just want to replace them?
Re: Downstream talk to ECU or only Up
No issues.. I’ve had almost every generation of Maxima; 87, 93, 96, 99. Every single one of them had the O2 sensor crap out around 90k. I know the O2 sensors with the MAF determine ratios for combustion. I’ve got 120,000 miles now and have read several articles stating much improved performance and idle. I’m the type to not wait on the engine light. I’m getting around 17-19 mpg on the hwy which I think is average for the F50’s.. I feel it can do better.. im Assuming the sensors have a range of acceptable or not. I’ve started hearing a slight miss in the morning on cold start. Not enough to register yet but I hear it. I think I’ve also got a idler pulley possibly going.. a supposed common issue.. I love the car and intend to drive until it blows up I guess. I saw a really really cool Cima imported into British Columbia and is at port now. It’s the Japan model with all wheel drive and cloth interior. 70k miles.. even has the Nissan accessories inside.. even those weird doily seat covers.. think it would be allowed here? Anyways, no issues, just hoping for some improvement..