View Full Version : P0140 and P1189 trouble codes
10-18-2005, 11:05 AM
Above codes have come up twice in the past week. Cleared them both times, once just before coming into school today. Anybody know why I'm getting these. I have an aftermarket Oil pressure gauge, but I've never had a problem in the past, had the gauge for two years. I also have a Magnaflow cat and a Caspers 02 sim (post cat). First time I've ever seen these codes....
Anybody have any insight?????
10-18-2005, 01:03 PM
If the PCM sees a constant voltage around 450mV coming from the 2nd O2 sensor for 90 consecutive seconds after the car goes into closed loop it will set the 0140 code, could a SIMM go bad? Not sure exactly what kind of signal a SIMM sends back to the PCM.
1189 sets if you have low oil pressure, I'd check connections at the factory oil pressure switch. I don't think the aftermarket gauge would affect this but I'm assuming that your oil pressure is OK?
10-18-2005, 01:09 PM
Overall oil pressure has seemed low at idle last couple weeks....was thinking about flushing engine this weekend. Problem is though...I don't have the factory sending unit hooked up to the car...took it off when I installed the oil press. gauge two years ago.
As far as the 02...is it just for the second sensor...or could it be the pre cat sensor on the downpipe???? I don't know if a sim can go bad, but mines only about a year old.
Thanks for the help
10-18-2005, 01:10 PM
Is there another oil pressure switch on our cars other than the one on the bottom front where I was told to install my oil press. gauge????
There's a sending unit that is for the factory gauge on the dash and then there's a switch for the PCM to monitor if it's low - I think.
Yeah the P0140 is for the second sensor only I beleive, which is where you have the sim.
10-18-2005, 01:19 PM
Damn...and that freakin sim was the solution to so many problems last year...piece of crap!!!
I would like to know more about this sending unit however. I'm thinking if its the one I pulled off...I can always Y the line off and put both sending units on. Not sure what exactly I would use, but I'm sure it's possible. If anybody has anything else I appreciate it; I'm tired of lugging my laptop out to my car to Autotap the damn thing.
Well I've been poring over the FSM and it calls it a switch one time and a sensor another time, then it says if it reads closed or open (like a switch) and the next time it'll say sensor signal. Hell in the schematic it shows a wire going from the "oil pressure switch" to the PCM terminal labeled "oil level switch". Anyhoo, I'm assuming at this point that there is one sender right up next to the filter. Did you just remove it when you hooked up the aftermarket gauge? Does any wiring from the aftermarket gauge hook up to the original connector. (I've never been much of one for mods :D )
10-18-2005, 01:45 PM
Only thing that the new one hooks up to is my new oil pressure gauge...so no...isn't attached to factory PCM wiring. But again...like I said....never had a problem with it in the past....if there is in fact another switch...I'm thinking maybe I just need to change my oil. I run Amsoil full synthetic...not the XL7500 stuff either. I get a discount on it where I work, its rated for 25,000 mile drain intervals...got about 10,000 on it now...got 15,000 out of the last stuff no prob...maybe it just needs changed....could bad oil cause a drop in oil pressure????
10-18-2005, 03:01 PM
Yeah, old oil, warm oil, thins out and can lower pressure on higher mileage engines, especially at idle. I've also found that synthetic oil of the same viscosity rating tends to be thinner, I know it doesn't make sense, but I switched from 5W30 dino in the hawk to 5W30 synthetic and it actually started consuming it, found it was a common problem, went to 0W40 synthetic and all my problems went away. Just for grins and giggles check your oil level, it may just be low too. And I would never go 10k on any oil, no matter what it says on the bottle, at least not on any car I'd want to keep. :D
Also, I could be mistaken, but the oil pressure switch won't turn your check engine light on, just set a code and turn your low pressure light on. Is it possible that the low pressure code has been set since you changed to the aftermarket gauge and you just never noticed until it set the O2 code which turned the light on?
10-18-2005, 07:23 PM
Yeah, old oil, warm oil, thins out and can lower pressure on higher mileage engines, especially at idle.
I've also found that synthetic oil of the same viscosity rating tends to be thinner, I know it doesn't make sense, but I switched from 5W30 dino in the hawk to 5W30 synthetic and it actually started consuming it, found it was a common problem, went to 0W40 synthetic and all my problems went away...
Yeah, most oils thin out over time.
But some (which is un-usually) actually thicken-up as it ages; like German Castrol Syntec 0w30 (which is almost a 40-weight oil) & Amsoil synthetic oils.
Smart choice going to a thicker oil, than the Mobil 1 5W30 synthetic that was factory-filled.
Others have said the LS1 engines prefer a thicker oil; & in Australia, they uses thicker oils in them.
What oil are you using, Mobil 1 0W40 synthetic ?
10-18-2005, 07:27 PM
Well...Looks like I'm changing my oil this weekend. I'm planning on popping some GTX or something in for about 1000 miles to try and flush the system. I suppose its possible that the oil light was there and i never noticed until the O2 code. Kinda makes me mad though...b/c i just bought the sim like 13 months ago. Guess I need a new one???
10-18-2005, 07:29 PM
Well...Looks like I'm changing my oil this weekend. I'm planning on popping some GTX or something in for about 1000 miles to try and flush the system...
You could use some diesel engine oil (that is API CI-4 rated) for flushing.
They have high detergents in them to suppress the soot & contaminates.
Or maybe use Mobil 1 Truck & SUV 5W40 synthetic engine oil for an regular oil change interval.
It really is just Mobil Delvac1 5W40 heavy duty synthetic diesel engine oil re-bottled for consumer use.
Just get it out before winter time extreme cold hits. As it is a really thick oil that 18-wheelers would use.
Dunno about the sim, like I said I've no experience with them. But I'd definately do some more extensive research and/or troubleshooting before just replacing it.
Mike Jung, yes I'm running 0W40 Mobil1 in my LS1.
10-18-2005, 08:42 PM
I'm gonna pop under there when I change the oil, make sure the LED is still lit up on it and everything. I know one of the guys that works at Jegs, he shops at my store all the time, so maybe he can set me up with a new one or soemthing if I have to. (thats the best part about Jegs, I can drive to any of their stores in an hour or less...one is only 15 mins away, main wharehouse is only 30 mins)
10-20-2005, 11:05 AM
Alright...changed my oil today. I had some 5w-30 sitting on the shelf so I just put that in there. Stuff that came out wasn't bad. Did smell too burned, it was pretty dark, but I've seen worse before. On my way to school, SES was still on and now my idle puts me around 20psi. I used to idle about 26 or so. This is a big drop. When I was filling the oil, I went to put the cap on and noticed that I could pull up on it just a little bit. Could a loose cap cause a drop in oil pressure???? If so I'm thinking that maybe I just need a new one. Are these things like radiator and gas caps in the sense that they can go bad???
I'm tired of staring at this SES light so please, somebody has to know something. My car is under extended warranty until 109k, but the deductible is $100 and I don't really feel like spending that if I don't have to. Plus, with my O2 code, its not like they can do anything anyways, since I have an aftermarket CAT and O2 simmulator.
10-20-2005, 12:31 PM
bump bump bump
10-20-2005, 09:01 PM
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