Last year I bought a 2005 Trailblazer LT, currently at about 146,000 miles, single owner, seemed great. I've been having so many issues with it, including having it stall in the middle of traffic on multiple occasions. I've taken it in to be looked at and no one can figure out why it's dying. I just dropped $1,500 getting new brakes and fixing the calipers and now I'm getting an "OIL PRESSURE LOW" message on the dash, then it just dies. I put it in park, take the key out, and restart it and it seems fine, but I don't understand the warning message since I just got an oil change a week ago. I can't afford to keep taking it in or paying a ton for repairs and I'm about ready to sell it. Any ideas what could be happening?

 

Welcome from Florida. Is the check engine light on and if it is, what are the codes? By the way, $1500 for a brake job seems very high to me.

 

Seems to me, reading all these posts that 2005 was not a good year for Chevrolet. vehicles, no matter what. You really need a pro to Dx this oil pressure issue with a VERY professional and costly scan tool. If your motor is running great and sounding A-OK it's likely an ECM issue, IMO. That or a bad oil pressure sensor, which can be a little hard to get to on some GM engines.

 

Yeah, it is unless he had a _complete_ brake job. New rotors, new calipers, ect. I agree. That's why no one goes to the dealerships, unless on warranty.

 

The check engine light isn't on, and they had to replace my front and back brakes because the calipers were bent and making a horrible grinding noise, it was basically metal on metal. The brakes are fine now, no more noise, but the oil pressure light came on yesterday and it was the first time I've seen it. What concerns me is that the engine died as soon as the message showed up, once again in the middle of traffic.

 

Even if it's just a bad sensor, would that cause the engine to shut off on its own? I've read some other post saying people turned their engines off but mine just died as soon as the message popped up.

 

Last Saturday I replaced the oil pressure sensor on the wife's '06 Trailblazer with the 4.2 engine. It's located right above the oil filter. Two things that will make it easy to change are a 27mm or 1-1/16" socket and a flex head 1/2" drive ratchet. A straight 1/2" drive ratchet will not have enough room to swing without hitting the frame, although a stubby ratchet might work. Do not put the truck on ramps, use a jack and jack stands. If the truck is on ramps, the suspension will compress and it can be a real bugger to get the oil filter out! Once the oil filter is removed there is plenty of room to change the sensor. Pull up on the wiring connector on the engine side, then pull the connector off. Put the socket on the flex head ratchet and slip it over the sensor. Crack the sensor loose and you should be able to remove the socket and unscrew it by hand. Screw the new sensor into place by hand till snug, making sure that the O-ring is in place on the sensor. If the new sensor didn't come with thread sealant on the threads, use a bit of Teflon tape on the threads. Use the socket and ratchet and finish tightening up the sensor, getting it nice and firmly installed, but don't over-tighten it. Put the connector back on and finish the oil change. Once the oil filter is removed it takes maybe 5 minutes if you take your time.
There are those on YouTube who will tell you to remove the right front wheel and try and snake your hand in through a hole in the frame. The above method is much easier. Since the OP has recently had an oil change done, the only added cost would be a new oil filter if the old one can't be unscrewed by hand and needs to be wrenched off.

 

I'm not a young professional technician and have never claimed to be one, but I am well versed in vehicle mechanics, nonetheless.

Spent all four years in the HS auto shop, then went to JC to become a true mechanic, as that term was in use back then and not automotive technician, as it is nowadays. Specialized in auto air-conditioning as it was not widely available, as it is standard these days.

Having said that, I in no way believe that an oil pressure sensor should be designed to shut a motor down. Back in my earlier years, that was not the case, and I don't believe any vehicle manufacturer would do so, besides some legal issues to boot. Shutting down a motor in freeway traffic could get someone killed, and you can bet a class action lawsuit would occur if an auto manufacturer did that.

In my early days, modern electronics were not a large part of a vehicle's design, and mechanical cables and the ignition system alone
usually amounted to spark plugs, one coil, and a distributor that worked with a crude mechanical "points system" that needed regular changing, along with the condenser and re-timing the motor..

The initial timing was done with a timing light that you pointed at the crankshaft balancer, while you turned the distributor to the required setting, usually TDC and locked down with a bolt, along with a vacuum advance system to the carburetor, and centrifugal weighted timing device incorporated in the distributor housing itself.

Since 1972-1973 the more modern "electronic ignition system" was adopted, partly due to the new SMOG regulations and as advances in automotive engineering, eliminating many of the older style devices, thus reducing smog emissions, at least according to the government.

Unfortunately, the smog regulations also manifested in lower compression ratio motors, thus the 1970's cars and other vehicles had much fewer horsepower, but also less gas mileage as well, than the 1960's models, and the SMOG pump was part and parcel of that reduction in HP, and was a pain in you know where to change out and costly as well. I know as.I chucked my fathers' C-60 SMOG pump in the trash bin myself as it was not required.

Then in 1986 fuel injected motors in gasoline vehicles hit the sales floors, compression ratios went up and the horsepower was BACK again!.

All that said, automotive electronics are still not perfected to the degree that they should have been by now, but I believe that it is still all these needless "gadgets" that we really don't really need, but almost every system in a modern car is controlled by the ECM, which is what I truly believe the issue is with your Chevy Trailblazer. My advice is to change out the oil pressure sensor as the ECM is not cheap.at all, nor is trying to reprogram it to function properly, and that is beyond my knowledge, at least presently.

Sorry for the long rant, but my once beloved 2015 Malibu TPMS system has let me down, and needs a new left front wheel sensor changed out. More useless electronic junk that I must deal with, thanks to all of these government safety standards we have to endure.

 

I have a similar issue with my 2008. Misfires on all cylinders and a p0017 code. Low oil would show up engine would die, oil is full. I did notice the p0017 code and I replaced the actuator and no more clatter, no lights on the dash either back to smooth sailing. I never knew such a part would somehow control everything in the top end. I was almost ready to take the head off to rebuild it, but now no need. Last owner seems to have never changed the oil. A 2008 which looked like it still had the original filter too!
I plan on changing the oil every two weeks till it shows up really clean on the stick. Only paid a dollar for it, clean on the outside and interior. He treated it like a throw away.