JPTL

UPDATE: If you're convinced that the sensor/switch is the culprit and are ready to jump in and replace, I strongly suggest that you read this post and some of the related posts in this thread.
The low pressure reading may not be from a bad sensor!

After some weird, erratic behavior, my '07 Suburban's oil pressure needle pegged at 80/3 o'clock on the gauge; then a few days later at 0/9 o'clock. It subsequently threw a code resulting in a non-clearable MIL.
Pretty compelling evidence that there was a fault in the switch/sensor, the connection or wiring. I concluded a bad switch/sensor.
Not being able to pass MD emissions with a hard code and not knowing the oil pressure, I knew I had to fix this (also it's my wife's car ). I ordered a new

AC Delco sensor/switch from Amazon

AC Delco sensor/switch from Amazon

and started to check into the cost of having the repair done at the dealership, or a good GM mechanic. Couldn't be too bad, right?
Wrong.
Everywhere I checked, starting with the dealer, quoted me $500 and up. All said that the intake had to be removed in order to access the $50 sensor & replace it. Ouch.
Being a DIY'er and a skeptic when it comes to dealer service, I decided to look into this myself. The sensor isn't visible from any angle when standing next to the engine bay. It isn't visible when lying on top of the engine. A chipmunk crawling back there could see it however. It's located waaay back there, screwed in to the top of the block vertically, behind the intake, roughly centered below the firewall cowl.
After some fumbling around, standing on the driver's side, leaning against the fender, I was able to touch it.
Okay, I thought, there has to be some angle where a DIY'er can get to this.
There is.*
It isn't pretty but it can be done. In 20 minutes!
You'll need the following, or else you won't be able to do this:

• A new switch/sensor
• Familiarity of how the plug goes into the sensor, and how the tab would snap on and off. Feel the tab on the sensor with your eyes closed because you won't be seeing any part of this plug at any time.
• A deep socket to clear the plastic top of the switch. I used a 27mm which was perfect
• An extension of the right height. No less, no more. Mine was a 5" extension.
• A ratcheting socket wrench. I used a 1/2 drive.
• A blanket, old lounge cushion or small dog bed
• A little patience
• A lot of dexterity
• Humility (you'll be crouched over the engine. What will your neighbors think?)

The total height of the socket, extension and top of the wrench are critical. My socket is 3"; the extension 5". With all snapped together, the total was 8 1/2" from the tip of the socket to the top of the wrench. Again this is critical as you have very limited space back there.
How to do it:

• Be prepared to do this job in one session. You don't want to remove the sensor and leave the opening exposed for any period of time.
• Start with a cool engine. You'll be crouched over it for 20 minutes.
• Pop off the intake cover from its rubber plugs by lifting the front & tilting up.
• Take your blanket/dog bed/cushion and lay it over the the driver's side of the engine
• In you go. You'll need your wrench/extension/socket handy
• While hunched over the engine, head almost touching the hood/firewall, reach back between the engine & firewall, going in on the driver's side of center.
• You'll find the connector harness as it plugs into the switch with a little lock tab.
• Find the tab and gently pry it upward at the same time, lifting the plug..not by the wires, but by the plug.
• When that pops off, grab your socket and worm it in under the fuel rail (I think) and snug it on the sensor
• Take the extension, settle it into the socket and snap in place.
• Snap the wrench into the socket and ratchet that baby out.
• Carefully bring your new sensor to the opening with your hand, not snugged into the socket.
• Hand thread the sensor into the threaded opening, taking care not to cross thread. Hand tighten as much as you can. Mine started to thread easily.
• Go in with the socket and settle it on the new sensor, then the extension, etc. Install the new sensor in reverse order, remembering to reattach and snap lock the harness plug.
• Using a OBD II tool, reset your code Key On, Engine Off.
• Start her up and watch that gauge come alive and the light stay off

This is where the patience comes in:
Take great care not to drop your socket, wrench or extension, as you'll need to be climbing under your vehicle to retrieve it if you're lucky and it falls through.Of course these can be retrieved with a magnet. Not the case with the sensor! It's aluminum, so a magnet isn't going to help. Dropping a tool or the sensor will surely turn a 20 minute job into a several hour ordeal.

*Ham fisted, impatient, DIY'ers with some degree of pride need not apply. Tell your mechanic that this absolutely can be done with the right socket/extension combo, and good hands - without pulling the intake, and he can do it in 1/2 hour and be all zipped up in less than one labor hour.

in2pro

Very nice! and thanks for the detailed how to DIY

Jcarter431

Thanks for the instruction. Looks like 2007 year has a longevity problem with switch. You would think they would put in a place easier to reach.
Did you use any treading tape for sealing or self seal? Jc

Jcarter431

Ok you need to add three Advil to the formula. I also bought a oil switch socket that helps removal and reset. Much patience needed and small to medium hands. Do not attempt if large belly or fat hands since yoga and meditation should be practiced prior to attempt.
Mission accomplished in three hours not 20 minutes. Can be done but as stated must be persistent . Jc

91Caprice

Great write up! My suburban just started doing this last night so it looks like I'll need to do this job

Slalom

Thanks for the write up. I am an oil change and brake pad type guy, but just completed this one in less than 20. I followed your suggestions , but tied some fishing line around my socket and the sensor, so I could fish them out if dropped. Never had to though. Harness popped right off when clip released. Able to feel threaded hole when finger starting the new sensor. Plus it was -5 degrees in mn today so I made sure the engine was warm while I was mounting her

MORAV

How timely, just got on here to find just this and there it was, right on top of the heap!


Was on the road, sans time and tools. Gauge at 0 with CEL on. Concerned enough that I had the Burb towed to Dealership. Diagnosed at Dealership and when I found out what the problem was, passed on them doing it, but they quoted it at $368.15 (parts and labor) plus tax and shop chg. Probably right at four bills out the door.


Bought part on eBay, $35.00 shipped. Now getting ready to do the work! Thanks for the great write up, very nimble fingers, but very large hands. Hope they don't prevent me from gaining access! lol


MORAV

rkent47

Fantastic!!! My son and I were headed out on an extended trip when the oil pressure gauge went to zero in his 2007 Suburban. He had been told the sensor was faulty and had gotten a replacement "just in case." We found this forum, used the step by step from MORAV and in 30 minutes, in the dark, my son changed out the sensor!!! Great step by step!! and it saved him a few hundred bucks on top of it.


Kent and Keir

lorenzep

Did this today. Can't thank this thread and this one, https://chevroletforum.com/forum/tah...n-39757/page4/, enough for the pictures. What a pain. I'm reading oil pressure again.

My question: does the light reset after x number of driving cycles or do I have to get the code cleared? 9/2@6:30 PM -code light went out by itself: two short start/stops; one twenty minute drive; 4th start -light was out.

Thanks,
Peter
Kensington, MD

in2pro

Peter, thanks for the follow up that the forum worked for you, following up on a fix or a repair is what makes the forum work!