Hi there,

Newbie to the forum so go easy on me !

I have a 2014 Mazda 3 2.2 Litre Diesel ... all was well with car until almost a year ago the red oil pressure light came on. I immediately stopped of course and checked oil level. It was fine. Car had recently been serviced and oil/filters changed so I was surprised.

Had it towed to garage and they said probably a faulty oil pressure sensor ... they replaced and cleared fault. Light stayed off for a day and then back on again. Brought back to the garage and they changed the oil and the filters and reset fault. Same again, light stayed off for a day and then back on again.

I have been driving the car around for almost a year with no engine problems ... garage said it could be faulty wiring to the sensor or ECU or software issue ... they don't know.

I have searched and searched online for an answer but all in vain. If anyone can help I'd really appreciate it !

Thanks,

 

Welcome to the forum

IMHO based on what you posted should have gotten a ECU flash!

 

Many thanks Callisto for taking the time to respond. I will look into getting an ECU software update.

 

It does not necessary need to be an update as more to simply "flash" the ECU with the most currently available ECU program even if it is the original. Flashing will reset everything in the ECU including all the clocks and all the settings back to as new! Often times this will solve some pesky "ghost" that seem to lurk around in the ECU PID files.
Most dealership will do this for free depending on the warranty and how far out of warranty the MAZDA is. But don't hold me to the free thing because that varies depending on the dealership?

 

Did you garage actually check/measure the oil pressure? or did they just fire the parts cannon?

 

Dude that is totally funny... I may have to use that in some future responses if you don't mind me stealing the phrase?

LOL

 

Lol. Yes they just fired the parts cannon ... boom !

No mention of an actual manual test of oil pressure.

 

Hey,
My reply to your query is not going to be one bit helpful.
On the contrary I am wondering if you can help me.
My 2014 Mazda 3 2.2 Litre Diesal has exactly the same oil pressure light on constantly as you have noted in the above. I have done all of the same things you have done and even got car towed away too.
I am wondering if you have got the to the route cause yet? Have you got it fixed?
Thankyou

 

Ok, I just joined this forum so I can provide you with an insight what's most likely happening here, although not limited to the information below.

There are few most common reasons why diesel Mazdas particularly report low oil pressure, and is not because of engine fault. The Skyactiv engines are designed with fuel efficiency and pollution in mind; therefore, they suffer of higher accumulation of carbon in exchange of lower emissions and increased fuel efficiency. Carbon buildup happens in multiple places: the intake manifold and valves, EGR pump and cooler, around the engine camshafts, timing chain and in the lower part around the oil pump, oil strainer and balancing unit. As the carbon builds up in the upper part of the engine due to incomplete combustion, especially when driving short trips on cool engine, the soot or mud (however you wanna call it), slowly descends down and clogs the oil strainer, decreasing oil pressure at specific RPMs and specific oil temperatures.

The incomplete combustion is a result to multiple things: Mazda decided to use copper washers on the fuel injectors, which can result in leaking fuel and mixing with the oil. This happens while the DPF filter regenerates and the car doesn't have enough time to complete the regeneration due to the short driving trips. The issue can be resolved by replacing the washers with steel ones and ensuring the fuel injectors are calibrated properly. The next is to clean up the carbon and I don't mean by using engine flush liquids. It requires opening the top of the engine, removing the fuel injectors, removing the camshafts, camshaft journals, tappets, and cleaning everything that can be reached thoroughly manually. The intake manifold and everything as an air intake system should be cleaned, air filter replaced, EGR cooler cleaned (or replaced if it's faulty), and so on. After the carbon cleaning is done in the upper part, the lower part needs to be cleaned as well. To reach the oil strainer, the oil pump must be removed and separated from the balancer unit. Both cleaned and the oil strainer replaced with new one. If you clean the lower part of the engine only and not the upper, then the soot will descend over time down again and clog the newly replaced strainer and oil pressure light will come on again. That's why it's important to follow these steps. Then, after everything is cleaned, o rings replaced and so on, new oil is added. Then you add engine flush fluid, flush the engine, remove the oil and add new oil again and you're good to go.

Tip: always inspect the engine when opened, especially the camshafts and camshaft journals for grazing. It can happen that something is damaged due to low oil pressure and is best to be replaced before it causes irreversible damage to the engine down the road. It might sound like this is extremely a lot of work, but it's not that bad. Yes, it's more than just flushing an engine or cleaning the car, but it is what it is and at the end of the day it's doable. The car will surely thank you for it.

Tip2: It can also be something as trivial as oil pressure sensor or switch. These should be inspected and replaced if they are faulty. They can also pop up the light on the dashboard. Although, based on your symptoms, it's unlikely that the sensor is problematic.

Hope it helps anyone facing similar issues.