I have a low oil pressure alarm on my Yukon after truck sat for 2 1/2 weeks the battery was dead (knew I was gonna need a new one) installed new battery drove it for about 10 mins then got low oil pressure alarm. I checked oil level was a quart low and replaced oil pressure sensor but I still have the alarm. If I start it and let run at idol pressure starts at 40 and drops to 25-20 once the engine warms up and will stay there until I rev the engine or start to drive once the pressure needle moves up it drops down to zero when I let off the gas then I get the alarm. Not sure what else to check.
Low oil pressure on 2014 Yukon
- Thread starter AWP84
- Start date
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mikez71
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So it sounds like normal pressure until you rev it up, then lift off of the gas pedal?
I didn't know there was a low oil pressure alarm! P0521 code?
Might check oil pressure with a mechanical guage.
Or check the signal data with a good scanner.. (look for intermittent signal cutting in/out vs. smooth gradual change? )
Maybe a wiring issue, and when lifting throttle, it causes a break in wire?
I didn't know there was a low oil pressure alarm! P0521 code?
Might check oil pressure with a mechanical guage.
Or check the signal data with a good scanner.. (look for intermittent signal cutting in/out vs. smooth gradual change? )
Maybe a wiring issue, and when lifting throttle, it causes a break in wire?
Marky Dissod
Full Access Member
No 'might', just do this.
Wholeheartedly agree with the rest.
swathdiver
Full Access Member
Seems to me that the o-ring on your oil pick-up tube needs to be replaced. Add two quarts of oil and face the truck downwards and see if the pressure stays up. If it does, you have your answer.
The oil light comes on the dash and a message low oil pressure stop engine appears along with constant dinging like a door is open.
I’ll give that a try thanks.
You also have the pressure relief valve in the oil pan that might have gone bad.
When you pull the oil pressure sending unit to check with the mechanical gauge, don't forget to extract the screen that's under it and see if it's plugged.
Since you have the sending unit out, I would go ahead and replace it regardless.... And only use the correct AC Delco one.
What concerns me is the pressure dropping when you let off the gas. Your oil pump is driven off the crankshaft, it's relative to engine RPM and not the gas pedal. If you still have the AFM/DOD, now that could react when you let off the gas pedal and affect oil pressure. (Because it uses solenoids that operate with oil pressure. Let off the gas and if a solenoid gets the electronic signal to do whatever and triggers the solenoid, it's going to pull some oil pressure. Nothing else really makes sense to me for letting off the gas and losing pressure.)
So if you pull your intake to check out your oil pressure sending unit and test it with a mechanical gauge, you should probably pull the VLOM plate and replace the o-rings under there. It would not be a collapsed lifter, because then you would be hearing it. So I'm leaning towards one of the solenoids. If that's the case, it's a great time to do the AFM delete. But if you want to keep it OEM, you might be looking at having to replace that VLOM plate.
Lol, that's my two cents worth
When you pull the oil pressure sending unit to check with the mechanical gauge, don't forget to extract the screen that's under it and see if it's plugged.
Since you have the sending unit out, I would go ahead and replace it regardless.... And only use the correct AC Delco one.
What concerns me is the pressure dropping when you let off the gas. Your oil pump is driven off the crankshaft, it's relative to engine RPM and not the gas pedal. If you still have the AFM/DOD, now that could react when you let off the gas pedal and affect oil pressure. (Because it uses solenoids that operate with oil pressure. Let off the gas and if a solenoid gets the electronic signal to do whatever and triggers the solenoid, it's going to pull some oil pressure. Nothing else really makes sense to me for letting off the gas and losing pressure.)
So if you pull your intake to check out your oil pressure sending unit and test it with a mechanical gauge, you should probably pull the VLOM plate and replace the o-rings under there. It would not be a collapsed lifter, because then you would be hearing it. So I'm leaning towards one of the solenoids. If that's the case, it's a great time to do the AFM delete. But if you want to keep it OEM, you might be looking at having to replace that VLOM plate.
Lol, that's my two cents worth
I think there might be an updated VLOM, too.
I like the add oil and park down hill test. if that's not it, I'd bet the new sensor is faulty. only buy the gm one from rock auto or the local parts department. all the parts stores and acdelco ones on Amazon are fakes.
the screen under the sensor is a good ideal. it probably isn't the issue thou as you have oil pressure. as for the vlom stuff, I have no gaskets under my vlom, all 8 ports are vented wide open to prevent afm lifter activation and I have no drop in oil pressure at all from doing it. the amount of oil that can get by the lifters up there isn't that bad and if a vlom solenoid was stuck open, you'd have afm lifter stuck open tapping and cyl misfiring from it.
the screen under the sensor is a good ideal. it probably isn't the issue thou as you have oil pressure. as for the vlom stuff, I have no gaskets under my vlom, all 8 ports are vented wide open to prevent afm lifter activation and I have no drop in oil pressure at all from doing it. the amount of oil that can get by the lifters up there isn't that bad and if a vlom solenoid was stuck open, you'd have afm lifter stuck open tapping and cyl misfiring from it.
Uh.... AC Delco has a storefront on Amazon. Buddy at the local dealer said they frequently get parts from there using the manager's personal account, instead of through normal channels which take longer and cost almost double. The products you buy from them on Amazon have the OEM hologram and everything.....
