Oil Pressure Low, Stop Engine warning on DIC. [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: Oil Pressure Low, Stop Engine warning on DIC.


turbonegro89
10-15-2011, 09:21 PM
Came to a light today and the RPMs dropped and I got a message saying Oil Pressure low, followed by Shut off engine. I changed my battery earlier this week and this happened. The oil level is good and I just cleaned the throttle body two days ago and this started today, was wondering if anyone had any ideas, thanks.


Sidenote, just under 150,000 miles

gregoryd12
10-15-2011, 09:35 PM
Did the oil pressure gage drop, also? They are controlled by same oil pressure switch.
How low did the RPM go?If you didn't do a thorough enough cleaning of the the throttle body and plate, front and back, it could have stuck and cause the engine to almost quit, and show low oil pressure, maybe.

turbonegro89
10-15-2011, 09:51 PM
Did the oil pressure gage drop, also? They are controlled by same oil pressure switch.
How low did the RPM go?If you didn't do a thorough enough cleaning of the the throttle body and plate, front and back, it could have stuck and cause the engine to almost quit, and show low oil pressure, maybe.

I don't actually remember, I just remember the RPMs dropping, when I looked over at the oil gage, it was normal. Not to be a smartass, but it was looking pretty good, I felt like it was cleaned pretty thoroughly.

Ralph_T
10-15-2011, 10:14 PM
Came to a light today and the RPMs dropped and I got a message saying Oil Pressure low, followed by Shut off engine. I changed my battery earlier this week and this happened. The oil level is good and I just cleaned the throttle body two days ago and this started today, was wondering if anyone had any ideas, thanks.


Sidenote, just under 150,000 miles

Did you disconnect the battery after cleaning the throttle body? Leave it disconnected for 30 minutes.

turbonegro89
10-16-2011, 01:20 AM
I had it disconnected for probably 15-20 minutes afterwards, I figured that would have worked.

Ralph_T
10-16-2011, 01:27 AM
I had it disconnected for probably 15-20 minutes afterwards, I figured that would have worked.

Some of the members have noted that there is a difference in the way some of the parameters clear from the ECM if the battery is disconnected longer. I disconnected my battery a few times for 15 minutes and then three or four times for over 1 hour. The times I disconnected the battery for over an hour the throttle body learned parameters were obviously erased because the idle was higher when I started it back up. You might want to let it sit a bit longer.

turbonegro89
10-16-2011, 01:48 AM
Okay, gnarly, I'll try disconnecting it for longer tomorrow, thanks. I also didn't know if this could be an oil pressure sensor or I think I read something about an oil pressure sender I believe.

Ralph_T
10-16-2011, 02:36 AM
Okay, gnarly, I'll try disconnecting it for longer tomorrow, thanks. I also didn't know if this could be an oil pressure sensor or I think I read something about an oil pressure sender I believe.

Not sure I am following you. You said the engine rpm's went down and then the oil pressure light came on. That would be consistent with low rpm's. I think your trying to jump to the conclusion that the oil pressure sender is bad. I wouldn't make that assumption unless the light comes on while driving and idling correctly. Right now were are trying to get your truck to idle correctly. You could also check the plug for the oil pressure sender. It sits directly below the power steering pump attached to the block. The plug could be contaminated with dripping power steering fluid. Nothing a little electrical contact cleaner couldn't solve.

turbonegro89
10-17-2011, 12:30 AM
Not sure I am following you. You said the engine rpm's went down and then the oil pressure light came on. That would be consistent with low rpm's. I think your trying to jump to the conclusion that the oil pressure sender is bad. I wouldn't make that assumption unless the light comes on while driving and idling correctly. Right now were are trying to get your truck to idle correctly. You could also check the plug for the oil pressure sender. It sits directly below the power steering pump attached to the block. The plug could be contaminated with dripping power steering fluid. Nothing a little electrical contact cleaner couldn't solve.

I had only jumped to that conclusion because when I was browsing and saw some of the same things happening to people and that was a consensus that a few people had came too. Regardings the RPM issue, it would fall from normal idle to just over 0 and then come back up again, only once it stalled but on my way home it would fall and come back up at nearly every stop light. :suicide:

Tatonka
10-17-2011, 01:47 PM
I had the exact warning light come on in my truck a few months back. I turned it off and few minutes later started it again and didn't have any problems. My wife got the message again just two weeks ago but it too went away. Oil level is fine, no leaks. I too am leaning towards the oil pressure switch/sensor and plan to swap it out at my next oil change. If you discover that something else is causing this warning light please post your findings.

Ray Dockrey
10-17-2011, 02:28 PM
Just to make sure did you take the throttle body off to clean it?

turbonegro89
10-17-2011, 05:30 PM
Just to make sure did you take the throttle body off to clean it?

Yeah, had it looking shiny and clean.

HardHeaded
10-25-2011, 09:55 AM
I have the exact same problem with the Low oil pressure warning and the gauge dropping to 0 at idle. It usually happens after driving at least 15 minutes and the engine is warm, when you stop at a red light or stop in the driveway and it drops to idle.
It first started over a year and 20,000 miles ago. I changed the oil pressure switch a year ago but it still did it randomly and has become more frequent lately. Tried changing the pressure switch again but it didn't solve the problem. Since the morons at GM put a bogus oil pressure gauge system in these trucks, I can't tell what the oil pressure is really doing.

I have been trying to find the problem for over a year, although I haven't thrown a oil pressure gauge on it. I might do that when I get time, just to see what I find on pressure but I still think it is a short in the circuit somewhere. Has anyone, traced the wires from the sensor back to see if one of them goes to ground and tried cleaning the ground? I am going to check that out this weekend. Otherwise, I think I am just going to build a jumper plug with a resistor for the pressure sensor connection and just take the sensor out of the equation to see if that will at least get the warnings to stop coming on every time we stop at a light.

Oddly enough, if memory serves me, I believe mine also started doing this after I cleaned the throttle body as I have seen others mention. I don't know if there is a correlation or not but it sure is one hell of a coincidence.

You would think that if it was really losing oil pressure, it would have started having an impact on the engine by now but the engine is still running smooth, quiet and still runs great. I got irritated the other day when it did it at a couple of red lights and I ran it through quarter mile runs off the lights as hard as it would go and it runs like new. I was tach'ing it up to over 5k rpms through the gears, pretty much just hoping it would come apart, but it continues to run just fine.

This trailblazer has been nothing but trouble since I first got it brand new in 2002. It had so many recalls, I lost count. It was at the dealer for a problem every few months the entire time it was under warranty and since the warranty ran out, I have had to work on it myself at least every 6 months but most of the time its something every 3 months. Its so bad that at times, I let things go for a couple of months so I can fix 2 or 3 things at once.

Thanks to this piece of junk, I finally quit buying American cars. I have been buying used Honda's and now have a Mercedes. Funny thing, the used Honda's and Mercedes are better and more reliable than any brand new American car I have ever had. We bought a used 92 Honda Accord back about 6 years ago when gas prices started going up, just to save on gas and we haven't had a bit of trouble out of it. lol

Sorry for the rant, but I am so sick of this trailblazer, I can't hardly stand to look at it anymore. It is my wife's vehicle and I have been trying to talk her into getting rid of it and buying a different car but she doesn't want to have to make car payments. Therefore, I keep having to work on this piece of junk. I think I am getting close to having her talked into it though. :hissy:

Ralph_T
10-25-2011, 10:07 AM
This trailblazer has been nothing but trouble since I first got it brand new in 2002.

:offtopic: rant

HardHeaded
10-25-2011, 10:13 AM
:offtopic: rant

Yeah I know, I went on an off topic rant....sorry, I 'm a little irritated. lol

I have been reading about this problem and there are a lot of threads from others with the same problem. A few fixed it with a new pressure switch but it seems for the most part the majority have never found the issue or at least if they did, they never posted the results. They may be doing like I have been doing and just driving it and ignoring the warning lights.

the roadie
10-25-2011, 12:40 PM
It's important to understand if the low oil pressure indication is a CAUSE or an EFFECT. I think in most cases, the oil pump is fine, the true oil pressure at idle is fine, and the engine is not being damaged. There ARE a couple of cases of deteriorating oil pumps that can cause lubrication issues. Relatively rare among trailvoy members.

The rest of the time, low oil pressure is a secondary EFFECT of erratic idle causing low RPM. Below 400-500 RPM, the oil pump will not provide sufficient pressure to activate the 12 PSI sensor switch. The cause of the low RPM has to be solved, and then the oil pressure indicator problem will solve itself.

Most often, it's a dirty throttle body that can be cleaned and the PCM forced to do a relearn cycle by the battery (or PCM fuse pull) trick. This sort of root cause often goes away when the AC compressor is forced to stop cycling by hitting the snowflake button.

Other times, the root cause of erratic idle RPM is old plugs, bad fuel, poor performance by the CPAS (camshaft position angle/actuator solenoid), CPS (camshaft position sensor), injectors, bad compression, flaky coils, sluggish upstream O2 sensor, or other items that can cause misfires. Many of these items, but not all, might set off a SES code indicating misfire (the P030X series).

A good scan tool that can capture freeze frame data can help analyze and home in on the root cause. A good scan tool in the hands of an experienced mechanic is invaluable. Not every problem is suitable to be solved by the average DIY'er. And problems that get solved by the professionals aren't usually discussed here, but on the pay-for sites run for professional mechanics.

HardHeaded
10-25-2011, 05:28 PM
Thanks for the reply. I understand the specifics behind the low pressure indicator. It is just frustrating that GM designed it the way they did where you really have no idea what is going on with the oil pressure. They made it a guessing game. It seems odd that so many are having this same issue and most never seem to resolve it.

I have a couple of excellent scan tools. One I built myself using a schematic found online that is based off of the elm328 chip. I etched and built my own interface that connects my laptop to the obdII port and I use a diagnostic program on the laptop. I can view sensor data such as O2 sensors, temperature but of course no oil pressure. lol
I also have a bluetooth OBDII interface and a diagnostic app on my android phone. Its not quite as extensive as the program on my laptop but it still gives me access to the DTC's and quite a bit of sensor data.

I'm not the average DIY'er. I have owned a construction company for years (although I am also now employed in another field) and I have always done all of the work and maintenance on our fleet of work trucks and vans. I have done everything from changing the oil, head gasket replacements, intake replacements, to numerous engine and transmission swaps. I can diagnose about any problem on a 89-98 Silverado just from a few given details and drawing from memory. However, these trailblazers can be a real pain in the rear and love attention. I never would have kept it this long had I known it was going to continuously be so much trouble. I mistakenly kept telling myself that I would eventually get to the point where all the bugs were worked out. :crazy:

If I get time, I will go through all the obvious things such as checking the actual pressure with a gauge and checking everything for dips in the idling but I haven't noticed any issues with idling. It may just be one of those bad component issues sort of like the ABS module issues on the 99-2006 silverado.

02blkws6
10-25-2011, 05:52 PM
Did you disconnect the battery after cleaning the throttle body? Leave it disconnected for 30 minutes.

You don't have to leave it disconnected for 30 minutes. Disconnect both negative and positive cables from the battery and hold them together for 10-15 seconds.

HardHeaded
10-25-2011, 06:12 PM
You don't have to leave it disconnected for 30 minutes. Disconnect both negative and positive cables from the battery and hold them together for 10-15 seconds.

The reason the battery has to be disconnected for a length of time is to give the capacitors in the various electronic components time to dissipate their energy. They can be discharged quickly by touching the battery leads together as you mentioned but what you are doing is causing a direct short in the system which could cause a sudden current draw and voltage spike across various circuits. This could lead to circuit damage and I would not recommend doing this but to each his own.

7secondmalibu
10-25-2011, 09:53 PM
Interesting reading. I just had my oil presure drop tonight and the shut off engine message come on. This is the second time it has happened. Once before about a year ago. 125,000 miles on a 5.3.

I would like to "T" in a analog gauge to compare the two readings. I figure the switch may be bad.

El Zopilote
11-17-2011, 03:44 PM
My 02 is just around 138k miles and is been showing up the low pressure oil and engine shut off warnings... I just reved her up and they go away... I came across to what The Roadie said.. to force the air compressor to shut off by pressing the snow flake button and it seems to be working for now... I already have the replacement for the sensor that is right above the oil filter to see if it will go away...

I been skeptical about taking her to the stealership to run a diagnostic for $120.00 for them to tell me that they couldn't find anything but thank you for my business, now that the cold weather is approaching and the AC compressor will be resting I think I can wait for my next oil change to replace the oil pressure sender...

I do have a whinning horrible sound all the time mostly when my AC is on which I have not been able to figure out yet.

Thanks for the info Roadie.

the roadie
11-17-2011, 04:57 PM
You probably need to also clean your throttle body and replace your idler or tensioner pulleys.

El Zopilote
11-17-2011, 10:57 PM
Tea that's the names of the pulleys... Thanks roadie

bromanjr
11-18-2011, 12:33 PM
Interesting reading. I just had my oil presure drop tonight and the shut off engine message come on. This is the second time it has happened. Once before about a year ago. 125,000 miles on a 5.3.

I would like to "T" in a analog gauge to compare the two readings. I figure the switch may be bad.

Just to clarify, this thread is for the I6 engine, it has a different Oil pressure sensor (on/off) and has issues with the throttle body getting gummed up easily. Be careful of the discussion here, it may not apply to your truck/engine.

The 5.3 V8 has an analog Oil pressure sensor (variable voltage output) and does not have the issue with the Throttle Body gumming up so frequently.

First of all, check your oil level. The 5.3 has a tendency to use oil. If your RPMs are dropping when you get the message, then a tuneup may be needed. If RPMs are steady, you need to check oil pressure with an external gauge. If you are actually losing oil pressure, then you have a big problem.

Ralph_T
11-19-2011, 01:17 AM
The Roadie has brought this up before.

I believe the same sensor is used by both the I6 and V8. The difference is that the I6 has the signal going through the PCM and is conditioned. The signal of the sensor for the V8 goes straight to the gauge. Therefore the sensor provides a variable output regardless of engine.

bromanjr
11-19-2011, 01:42 AM
The Roadie has brought this up before.

I believe the same sensor is used by both the I6 and V8. The difference is that the I6 has the signal going through the PCM and is conditioned. The signal of the sensor for the V8 goes straight to the gauge. Therefore the sensor provides a variable output regardless of engine.

Not true, they are different parts. The I6 sensor is an open/close switch and the V8 has the analog sensor. You are right that the I6 PCM approximates a pressure based on temperature and RPM.

Ralph_T
11-19-2011, 02:00 AM
Not true, they are different parts. The I6 sensor is an open/close switch and the V8 has the analog sensor. You are right that the I6 PCM approximates a pressure based on temperature and RPM.

If they are different sensors then I guess Advance Auto is wrong. I was curious myself and just did a quick search on their site and the same sensor is called for in both the I6 and V8 for a 2002 TB EXT.

WOOLUF1952
11-19-2011, 03:09 AM
If they are different sensors then I guess Advance Auto is wrong. I was curious myself and just did a quick search on their site and the same sensor is called for in both the I6 and V8 for a 2002 TB EXT.


I don't believe there was a V8 available until 2003.

Ralph_T
11-19-2011, 06:36 AM
I don't believe there was a V8 available until 2003.

Meant to say 2005, not 2002. But yeah that's the result I get.

the roadie
11-19-2011, 10:32 AM
Parts stores are wrong more often than the collective wisdom of trailvoy. Like the notorious serpentine belt length question.

TheGary
11-19-2011, 11:08 AM
Parts stores are wrong more often than the collective wisdom of trailvoy. Like the notorious serpentine belt length question.

You will become one of us, resistance is fuitile! :thumbsup:

WOOLUF1952
11-19-2011, 04:57 PM
Auto Zone lists different part numbers for the 2003 V8 and I6 oil pressure switch.

turbonegro89
11-25-2011, 04:18 PM
I haven't had any problems recently with the oil pressure low sensor, but now my transmission is acting up. It sounds like a hose is leaking whenever I accelerate and feels like it's slipping because it didn't want to shift out of first gear with the RPMs jumping up to around 6000.

Daddy Mitzo
12-09-2011, 12:53 PM
I had this same problem occurring with the rpms dropping, engine shutting off and Dic indicating low oil pressure over a year ago, as always I came here and replaced my oil pressure switch(05 I6 85,000 miles) and my problem went away and untill this morning same thing happened? Prob purchased a low quality switch.. What do I guys think?

aydenrooster
02-13-2012, 10:21 PM
My 02 trailblazer would tell me low oil pressure stop engine,but no other symptoms,only at idle sometimes,i pulled the plug on the oil pressure switch above the filter and i was dripping oil like it failed internally,i replaced the switch and cleaned the connector with contact cleaner.we,ll see what happens now.:)

kooltrini
02-17-2012, 07:31 PM
For those who still need help with this issue. I had the same, EXACT problem...no check engine code. Car would choke, then shut off, then turn back on and work fine for a little and repeat the process. I replaced the Oxygen Sensor on bank 1 and it solved the problem.. 100%.

trailbabysh
02-17-2012, 09:26 PM
I had the same problem for the last 3 years, this would happen like 3 times a year. Ever since I have replaced my fuel pressure regulator due to it's malfunction, the problem has stopped. Just a note. :undecided

aydenrooster
02-18-2012, 07:26 AM
it worked ! no more problems.thanks everyone.

El Zopilote
03-19-2012, 01:58 PM
I have cleaned my Trottle body and replace both pulley iddler/tensioner and also replace the oil pressure sender/switch/sending unit... and every now and then I get the same issue as I stated before and everyone else has mentioned... so I been managing to keep my foot on the gas pedal just enough to keep my RPM right about 600-700 before they drop and the oil gauge drops, and all the messages start showing up, and that seems to prevent the everything.

HardHeaded
04-03-2012, 08:42 PM
Has anybody ever managed to solve this issue? I have tried every suggestion I could find and everything I can think of and the Oil pressure gauge still drops and warnings come on every time you stop once the engine has warmed up after driving for around 15-20 minutes.
I need to get this fixed as we are ready to sell it and be done. I have to find a way to fix it as nobody in their right mind will buy a truck that sits there and claims to have no oil pressure. Nobody would ever believe me and take a chance on it anyway after I tell them it has been doing that for over two years and if it was really losing oil pressure the motor would have gone out by now. Hell I let it sit there idling with it claiming to not have any oil pressure for almost a half hour one day, hoping it would blow up. lol

Shawnvad1145
01-14-2013, 12:18 PM
HardHeaded: I was reading around a bit and came across a post that mentioned a remedy. The post said to change the Camshaft Positioning sensor and that should fix the issue. I too have the same problem, and have replaced the sensor in my 02 TB LT. I wont be able to give you a 100% answer just yet as my drive-shaft is out and im replacing the universals. Once its back together ill let you know if that fixed my problem.

HardHeaded
01-14-2013, 07:58 PM
HardHeaded: I was reading around a bit and came across a post that mentioned a remedy. The post said to change the Camshaft Positioning sensor and that should fix the issue. I too have the same problem, and have replaced the sensor in my 02 TB LT. I wont be able to give you a 100% answer just yet as my drive-shaft is out and im replacing the universals. Once its back together ill let you know if that fixed my problem.

Cool! I hope it fixes this issue. There seem to be a lot of people with this problem that haven't been able to find a solution. Let us know how it turns out for you.

GM Lover
01-15-2013, 01:23 AM
I replace the oil pressure switch and solve the issue.

Shawnvad1145
01-15-2013, 04:31 PM
Cool! I hope it fixes this issue. There seem to be a lot of people with this problem that haven't been able to find a solution. Let us know how it turns out for you.

Got the Universals put in and the drive shaft back on. To my surprise now im getting an awkward bouncing idle. Has been sitting for a while running hoping that the computer will re learn. If that dont solve it im going to clean the throttle body front and back and then take it for a ride and see about the Cam-shaft sensor that I replaced. Hope it fixes the LOW OIL PRESSURE warning that I hate oh so much. Ill let you know :)

Shawnvad1145
01-16-2013, 01:04 PM
Hey guys, just wanted to give you an update.

MY PROBLEM: The vehicle would start and idle no problem. Driving seemed fine, when I stopped the truck it would drop in RPM's and the heads up display would flash OIL PRESSURE LOW and then die out. It would restart with no issues. So After looking and looking and testing and testing here are my results and my fix.

MY FIX: I swapped out the Cam-shaft positioning sensor. This may seem odd to some but guess what! It worked. I spent $34.99 and about 5 minutes of removal and installation.

Good luck to you all if you have the same issue!

MY VEHICLE:
2002 Chevrolet Trailblazer LT 168,000 miles. :grouphug: