2005 Avalance Low Oil Pressure on gauge after warming up

Asked by Feb 22, 2017 at 11:42 PM about the 2005 Chevrolet Avalanche 1500 LT 4WD

Question type: Maintenance & Repair

Hello folks,

I have an interesting problem that differs slightly from what I've seen
floating around the internet regarding this issue.

Vehicle info:  2005 Avalanche 1500 LT  4x4 with 5.3L Vin Z flex fuel engine,
but I run standard 87 octane.  I just purchased it recently and it has 175k
miles, with about 3000 hrs on the engine (averaging something around
50mph, mostly highway unless there is a glitch in the hour reading)

Issue:  Oil pressure gauge at about 45psi at cold idle, which drops to
around 25psi when warmed up, then after a few revs, or driving around, will
eventually drop to near 0psi at idle, and 15 psi when revving.  The engine
makes zero noise, it's actually one of the quiestest engines I've ever heard.  
Additionally, when the gauge is reading 0, there is no chime, red light, or
any low oil pressure, shut engine off warning on the information display.

What I've tried so far:
1)  Disconnecting Oil Pressure sensor:  Gauge stays at zero, but no
warning chime or low engine oil pressure, shut down in information section
of cluster which I find strange.
2)  Oil change:  The old oil was dirty but not the worst I've seen (I did not
change it last so not sure what type of oil was in there).  It had an AC Delco
filter.  I changed to 5W30 Mobil 1 synthetic and a purolator filter.  No
change in oil pressure.
3)  Oil pressure sensor:  I pulled the old one and put a new one on,
measured both with a multimeter and the old one had very high resistance
(about 400k ohms, yes K), the new one has about 200 ohms total, 135
ohms between 5V and signal, 65 ohms between low ref and signal, 200
ohms between 5V and low ref.  This did nothing, the gauge behaved the
4)  Manual Oil Pressure Tester:  I hooked up an Engine Oil Pressure Tester
gauge at the sending unit port.  I had to use a stretch of about 5ft of nylon
hose used for manual gauges in a gauge kit, and there was a fixed larger
rubber style hose attached to my Harbor freight gauge, making for about
10ft total of hose, with the nylon hose restricting flow a bit.  Considering
there is no flow to the gauge once the fluid fills the entire space, figured this
would be fine.  The pressure was slow to rise with this setup but went up to
40-45psi cold idle which matched the gauge in the car, but only dropped do
about 34psi when warmed up (coolant at 200F according to scan tool, idled
for 15-20 minutes).  Clearly unless my setup is flawed, the oil pressure is
fine.  The engine sounds fine as well, it's so quiet I can hear the injectors
5)  Wiring Tests:   I tested at the oil pressure sending unit for 5V with key
on, checked continuity from ground to a good vehicle ground, and then did
continuity checks all the way back to the PCM for all 3 wires and everything
checked fine.

Tech Review:  In this vehicle, the oil pressure is measured using a
potentiometer style oil pressure unit, and the PCM reads a voltage from it,
converts it to temp and sends it out on the data bus.  The cluster picks it up
off the bus then converts it to a reading on the needle.   What I do not know
is where the low engine oil pressure warning comes from.  Does the cluster
determine this simply from the oil pressure value on the bus, or does the
PCM send another message for it?  

In other posts for oil pressure problems, most folks get a chime and a low
oil pressure warning, please shut engine off.  They also often have an error
code reported and a service engine soon light.  I do not.

Currently, since my cluster has a few other minor problems (needles are a
bit notchy when they move indicating the stepper motors are fading) and
some lights are burned out, I'm ordering a dorman remanufactured cluster
for $190ish pre-programmed for my vehicle.

I do not have a GM Tech 2 tool to be able to read what the PCM interprets
oil pressure as being, which prevents my ability to troubleshoot out of my
own back yard.

Any advice would be appreciated.  I know I wrote a bible about it, but
maybe it will help someone else.  

Thank you.

5 Answers


I think your dash gauge is faulty. If it had no oil pressure at some point it would start to tick or knock, Since your looking it over I would see if the rest of the sensors are in range, may help keep it from being broke down in the future.

1 of 1 people found this helpful.

I've ordered a dorman remanufactured cluster, should be in early next week. I'll let you know how it goes :)

For all following or interested in this thread, the remanufactured gauge cluster from Dorman solved the issue. The oil pressure matches the manual oil pressure gauge reading now. I'm getting about 40 psi cold idle, 30-35psi warm idle. 40psi at 1krpm warm, 50psi at 2krpm warm. Hopefully the information I provided will help others solve their issues. I noticed my old cluster gauge (tachometer and speedometer gauge also) were a bit notchy, and didnt move smooth. That has been solved as well with the new cluster.

Good Info, Noted, thanks

I am having this exact problem to the T with my 05 avalanche. only thing I'm getting is oil gauage is very low. I did oil change, air filter, spark plugs and wries, changed the sending unit almost verbatim what was originally posted. rpm gauge is out and lights are out on gauges aswell, simular to original post. my question is, am I good to drive now? I'm going to order instrument cluster now, but is truck good to drive as is?

Your Answer


Looking for a Used Avalanche in your area?

CarGurus has 5,055 nationwide Avalanche listings starting at $2,250.


Chevrolet Avalanche Experts

  • #1
    Tom Demyan
  • #2
    David Scott
  • #3
    Oscar Leon
View All

Related Models For Sale

Used Chevrolet Silverado 1500
2,422 Great Deals out of 174,001 listings starting at $699
Used Ford F-150
2,847 Great Deals out of 213,211 listings starting at $1,295
Used Chevrolet Tahoe
791 Great Deals out of 42,136 listings starting at $1,980
Used Cadillac Escalade EXT
20 Great Deals out of 622 listings starting at $3,999
Used GMC Sierra 1500
1,143 Great Deals out of 65,565 listings starting at $1,750
Used Dodge Ram 1500
421 Great Deals out of 10,816 listings starting at $1,499
Used Chevrolet Colorado
313 Great Deals out of 36,737 listings starting at $1,995
Used Cadillac Escalade
251 Great Deals out of 12,116 listings starting at $2,000
Used Toyota Tundra
597 Great Deals out of 35,468 listings starting at $2,900
Used Toyota Tacoma
668 Great Deals out of 46,330 listings starting at $2,700
Used GMC Yukon
591 Great Deals out of 22,299 listings starting at $2,500
Used Chevrolet Suburban
430 Great Deals out of 23,885 listings starting at $1,799
Used Chevrolet Silverado 2500HD
330 Great Deals out of 30,638 listings starting at $2,499
Used Dodge Charger
355 Great Deals out of 30,264 listings starting at $2,000

Used Cars For Sale

2013 Chevrolet Avalanche For Sale
14 Great Deals out of 492 listings starting at $12,977
2012 Chevrolet Avalanche For Sale
4 Great Deals out of 253 listings starting at $10,995
2011 Chevrolet Avalanche For Sale
16 Great Deals out of 463 listings starting at $10,800
2010 Chevrolet Avalanche For Sale
16 Great Deals out of 281 listings starting at $10,900
2009 Chevrolet Avalanche For Sale
6 Great Deals out of 308 listings starting at $10,535

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.