P0521 & P0523 - Malibu 2013 2.5

02-12-2020, 08:01 AM
As the title suggests, those are the codes thrown out by car. I believe these showed up a month, more or less, after an oil change from an oil place.

After seeing a few videos and reading a few boards, I changed the oil pressure sensor, as well as oil & filter; I did this myself with the good stuff. Sadly, after clearing the codes and disconnecting the battery for good measure, the codes returned - vengeance!

The codes returned but now the car began to sputter and stall. Perhaps the weather conditions didn't help, it was a rainy day. As an addendum to Murphy's Law, everything wrong with a car will be manifested on a rainy day. Slow traffic, whippers going full blast, defrost... car stalls... car shuts down. I realized that putting the car on neutral caused the car NOT to stutter or stall, so that's what I did and made it home. But I digress.

I plugged the scanner and it is detecting two contradicting positions: 1) an oil pressure 120 - 140 psi and 2) oil pressure switch low. with an alternating oil pressure control solenoid valve on/off.

I'm leaning towards replacing the control solenoid and oil pressure pump, any thoughts?

02-12-2020, 08:34 AM
Look at this. https://www.fixdapp.com/blog/p0521-code

02-12-2020, 02:06 PM
Hey Thanks! I replaced the oil pressure sensor and the code returned. I am left with exploring the cause behind the high read with low pressure.

02-18-2020, 03:05 PM
Took the car to a local auto repair franchise and they too replaced the oil pressure sensor. The codes remain and continue to show a high PSI, a high voltage, and low pressure.

On the one end, it validates my DIY. On the other end, should they tell me other parts need to be replaced, like the oil pressure control solenoid valve, or worse the oil pump (a dealer part); this repair bill is gonna be a doozy.

02-19-2020, 01:41 PM
Just got a call from the shop. Get ready folks, they recommend replacing and flashing the ECM $400 + $350 labor.

I told them no and recommended to replace the oil pump to which the shop foreman / technician admitted that they saw the same information on the net but figured that probably wasn't it. Two things from that exchange: 1) certified mechanics are searching the net for information just like the rest of us and 2) they will always recommend the most expensive option.

I reminded him that I originally asked for an oil pump but decided to let them do all the diagnostics because, well why not? I could've missed something? I don't have the fancy equip they have, so I am willing to eat the cost of re-doing the diagnostic AND new oil pressure sensor.

So far, I'm in the hole $300 (2 $50 oil pressure sensors + 200 labor). Let's see this oil pump.

Anyway, they are going to replace the oil pump which is cheaper than getting and flashing a ECM.

If that doesn't work, I'll take it else where. I don't believe in throwing too much money in ONE shop. But let's see.

02-19-2020, 02:15 PM
This just in, the shop informs me that even though the oil pump is $150, the labor which involves "dropping the engine" is about 12hrs. Is that even possible?!

I told them no worries, take the car out on the lot, I'll pick up the car later with my spare.

02-19-2020, 02:34 PM
Check this out, the pcm has at least a 7 year 70 or 80k warranty, check the emissions warranty book, comes with the owners manual.

02-19-2020, 02:38 PM
Oops, I'm so out of luck on that becaaaaussse, my vin is "branded" ie salvage car. Make no mistake however, the I've the car for 10 months, no problems til now.

Thank you very much!

02-19-2020, 04:35 PM
SOLVED!!! But not without a back story.

As I said, the shop changed the oil pressure sensor but the high pressure and light kept coming on, so they told me. I had no reason to not believe them because I too changed the sensor leading me to believe it was something else. My idea was, oil pump fail and was willing to go that route until the shop offered to change the ECM/ECU whatever. Both ideas were expensive. So I declined.

Picked up the car, check engine light on with 58 OBDII codes. Clearly a crazy error and deleted them all. Drove it around, picked up some groceries, got home, checked the oil etc etc... plugged the OBDII again, ran the oil pressure test... and... Well I'll be damned! 25 - 40 psi!!! In other words NORMAL!!! WOOWHOOO!!!

Why was I recommended a new ECU? I don't know. The lesson? Change your own oil if you can or make sure you don't get the bulk oil. Be wary of Dorman parts, AC Delco for GM or Denzo. Beware of shops trying to scare you into spending more money - Patience.

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