Dreaded oil pressure max
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Joined: Aug 2003
Posts: 80
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From: honolulu hi
Dreaded oil pressure max
ALoha friends, Like most of C5 owners I have fallen to the oil pressure sending gauge MAX reading failure which seems to be common problem! Actually the oil pressure gauge had been maxed out for years and now that I am retired I decided to finally get off my rear and fix it. I changed out the unit taking care not to over tighten (as indicated in numerous posts), and when I fired it up my gauge no longer reads MAX it now reads O and I now get a Service soon flash. I ran the codes and the only code was PCM PO522 which is low voltage error to the sending unit I just changed. I did notice that when I unhooked the electrical lead to the unit that it had been pulled apart and had exposed the wires. They did not look damaged so put it right and I plugged it back in but what I do not know is if this could be the problem and need to change this pigtail along with another new sending unit. Any suggestions would be appreciated as I do not want this one problem to become my life's work! Thanks
Instructor
Joined: Jul 2014
Posts: 194
Likes: 6
From: Austin Texas
Did you fully repair the damaged wires? I would try that first. If that doesn't seem to resolve it, I'd try another sensor as they are prone to failure and could have been bad out of the box. Next, I'd try changing the pig tail if that did not work.
Advanced
Joined: Feb 2008
Posts: 77
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From: Winter Haven Florida
I am having the same prob. Mine has been stuck on max for a few years also and recently changed the sensor. I have changed my PCM twice since this occurred due to other issues. And pressure reading was the same after new PCMs so I don't think it's PCM related in my case. When I installed the new sensor it worked for about a day and the next day it slowly started creeping up to max over a period of driving 30 minutes. I guess the sensor could be bad but I'm wondering about the wiring from the sensor to the PCM.
I used a gm sensor, not sure if you are better off with something non-gm from a local parts store?
A while back there was a bundle of wires under the battery tray that got tore up from rubbing on the side of the battery tray. This caused the headlights not to go up/down, but I'm wondering if the oil pressure wires are in that same bundle of wires. I am leaning toward the wiring as my prob.
I used a gm sensor, not sure if you are better off with something non-gm from a local parts store?
A while back there was a bundle of wires under the battery tray that got tore up from rubbing on the side of the battery tray. This caused the headlights not to go up/down, but I'm wondering if the oil pressure wires are in that same bundle of wires. I am leaning toward the wiring as my prob.
Race Director
Joined: May 2012
Posts: 15,776
Likes: 3,284
From: Phoenix area, AZ
If either of you used the OEM replacement your problem could be the sending unit itself as they have been known to be bad out of the box, or fail quickly. For the OP, I would check those wires and the plug itself again.
The brass version available at many parts stores (BWD I believe is the brand) is the best replacement part to get.
The brass version available at many parts stores (BWD I believe is the brand) is the best replacement part to get.
Drifting
Joined: Sep 2009
Posts: 1,719
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From: cinnaminson n.j.
St. Jude Donor '14
Do a search, the brass sensors are preferred. I think rock auto has them. Get a new pigtail from gm. The switch relocation kits are also very popular.
If you want to test it first, clamp a rubber hose around the sensor and apply air pressure. Make sure you don't exceed 75psi. Have someone in the car with the key on watching the gauge.
If you want to test it first, clamp a rubber hose around the sensor and apply air pressure. Make sure you don't exceed 75psi. Have someone in the car with the key on watching the gauge.
Last edited by martysauto; Oct 14, 2014 at 06:41 PM. Reason: Added info
Thread Starter
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Joined: Aug 2003
Posts: 80
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From: honolulu hi
bought a new pig tail today and I will try that this weekend, if it still does not work properly I will change the sensor again.
Burning Brakes
Joined: Jul 2014
Posts: 1,170
Likes: 253
From: Oconomowoc Wisconsin
Do not buy the AC Delco aluminum oil pressure sensor. They have been known to fail quickly. Buy the BWD brass oil pressure sensor. You can get them O'Reilly's Auto Parts stores and probably from other national auto parts suppliers.
Thread Starter
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Joined: Aug 2003
Posts: 80
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From: honolulu hi
Victory at last!
Thanks all appreciate the info, now for the good part! everything works proper now! Oil pressure great and no codes! Got the new pigtail from Rock auto, my usual go to guys and just as I thought one of the connector wires had broken inside of the cover and half way up the pigtail two of the wires had joined (melted from heat). I would have never found them unless I trimmed the wires 6 inches back. Went ahead and changed the sensor to a O'Rielly brass unit. (its taller and more easy to work with than the shorter GM unit) One thing I did notice was the PCV hoses from the right side of engine to the drivers side rear were shot and looked like melted rubber! Looked all over for the complete hoses and found them at Davies Corvette parts in Florida. They had the complete OE set. One final thing, I was able to change the sensor without pulling the intake. There is a guy on U tube that gives a step by step on how to change it, I did modify some of his steps and tools which made a big difference and if anyone wants to know how I did it just email me! Thanks for all the input! Mahalo!
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Thread Starter
Advanced
Joined: Aug 2003
Posts: 80
Likes: 1
From: honolulu hi
I am having the same prob. Mine has been stuck on max for a few years also and recently changed the sensor. I have changed my PCM twice since this occurred due to other issues. And pressure reading was the same after new PCMs so I don't think it's PCM related in my case. When I installed the new sensor it worked for about a day and the next day it slowly started creeping up to max over a period of driving 30 minutes. I guess the sensor could be bad but I'm wondering about the wiring from the sensor to the PCM.
I used a gm sensor, not sure if you are better off with something non-gm from a local parts store?
A while back there was a bundle of wires under the battery tray that got tore up from rubbing on the side of the battery tray. This caused the headlights not to go up/down, but I'm wondering if the oil pressure wires are in that same bundle of wires. I am leaning toward the wiring as my prob.
I used a gm sensor, not sure if you are better off with something non-gm from a local parts store?
A while back there was a bundle of wires under the battery tray that got tore up from rubbing on the side of the battery tray. This caused the headlights not to go up/down, but I'm wondering if the oil pressure wires are in that same bundle of wires. I am leaning toward the wiring as my prob.