2005 Trailblazer Oil Pressure gauge Problem
Asked by MEgus May 07, 2019 at 11:09 PM about the 2005 Chevrolet Trailblazer LT 4WD
Question type: Maintenance & Repair
I have a 2005 Trailblazer with the 4.2L engine. It only has 78,000 miles on it. The oil pressure gauge will start at 40 pounds, but when it warms up it drops to 0. It is not the actual pressure. That checks out just fine. The pressure sensor also checks fine. If you turn it off and right back on, it jumps to 40, but after a while drops back to 0.
I've done a lot of research and found the gauge itself is not actual oil pressure. The cluster gauge does work, so I don't think its motors. I have found several links to people with the same issue, but can't find any that actually found a solution to this problem.
Anyone have an idea how to fix this???
5 Answers
Well, I just cleared the PCM and will see what happens there. If that does not work, I will clean the throttle body and try it again.
Well, that did not work. At first it looked like it might, but then dropped to 25 pounds and as soon as it was warmed up all the way, dropped to 0 at idle again. Anyone have any ideas?
I looked at the BCM video you were referring too, and I don't have any of those symptoms. The vehicle does have oil pressure. It's just the stupid gauge. And the sending unit is fine. (New and checked) From what I have read and heard, that leaves just cleaning the throttle body and the vvt selonoid. Not sure why these two would have any bearing on it though. Anything else???
MEgus, it's your oil pressure switch, swap it out. On the I6 engine, it's located right above the oil filter. Look at it, likely it has oil on it, which means it's bad. Not a bad job to do yourself. It's a VERY common problem on our GMT360 platform. I personally had same problem 2 weeks ago.
Thanks! I tried that already. New switch. Same problem. Even watched the video about being able to disconnect and the gauge would stay at 40 pounds. Tried that too. Nope, Drops to 0 when it gets warm and stays there, Actual oil pressure 70 pounds at 2000 RPM. It's something else, and so far I have not heard of anyone actually finding a solution to the problem. I'm still working on it. Will try some more things tomorrow.
