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HI all

I have a Mazda 6 2.2d Skyactiv 2015 (103Kmiles) and recently I have been experiencing similar problems to some of the previous posters. I now think I have solved my issues and thought I would share some feedback.

The problem started approximately 18 months ago (80Kmiles) with a noticeable flat spot at low-speed acceleration. Gradually and more frequently the engine management light and/or warning triangle would illuminate with various faults logged which were mainly:

P0101 - Mass or Volume Air Flow Sensor A Circuit Range/Performance
P2262 - Turbocharger/Supercharger Boost Pressure A Not Detected – Mechanical
P258B - Vacuum Pump Control Circuit A Range/Performance

As time progressed “SCBS Forward Malfunction” (Smart City Brake Support) started to illuminate on the dashboard, mainly when braking after a period of motorway driving. Interrogating the codes showed various other minor faults would also be logged relating to the anti-lock brakes, electric parking brake, stop start unit and other electronic modules.
Mostly, the car’s performance was acceptable, so in parallel with checking the sensors pipes, wiring etc, I would just reset the faults and carry on using the car as normal.

Without warning, my DPF became blocked (Code P2463- Diesel Particulate Filter – Soot Accumulation too high) which was a little surprising as I drive 80 motorway miles per day. I had nothing to suggest the car was not regenerating during this time but it mustn’t have been. I was unable to carry out a static regen due to the level of blockage and had to have the DPF removed and cleaned. I now know that some of these faults inhibit regen whilst active and they were occurring quite frequently.

TIP: If you are using a diagnostic tool/scanner, keep an eye on the DPF regen count every week or two. If it is not increasing carry out a static regen. The DPF is expensive to remove for cleaning as it is located between the engine and bulkhead and requires removal of the front subframe and steering rack.

At the same time as the DPF clean, I replaced the Exhaust Gas Pressure Sensor No1 as there are reports that this sensor can cause P2262 faults. Many people on forums have reported that replacing this sensor cured their faults. Mazda have upgraded this part due to unspecified problems so I thought it was worth a shot. The sensor sits on top of the engine at the back, under the heat shield. The original sensor is a plastic block with an orange rubber cover whereas the new part is stainless steel and circular. For me, this made no difference.

Later during my ongoing investigations, I removed my injectors to replace the sealing washers as these have also been upgraded by Mazda. The original washers did not seal correctly and caused blow-by, diluting the engine oil with diesel. Whilst the injectors were out, I removed the head “Rocker” cover and found very significant wear on the exhaust camshaft lobes. Further research revealed this is a common problem and in most cases is related to the camshaft quality rather than oil starvation. (See the photos in the earlier post from Sigour.)
I replaced the camshaft and followers which made a significant improvement to the performance and fuel efficiency. Acceleration became much sharper and consumption is now up from 43mpg to 53mpg on the motorway. The camshaft replacement isn’t very difficult provided you are competent with the spanners and understand the importance of its alignment on the timing chain.

To my dismay. I was still logging P0101, P2262, P258B, SCBS etc.. on a regular, if not daily basis.

Further research uncovered reports that metal fragments from the worn camshaft can find their way into the vacuum pump and grind the seals, thus reducing its efficiency. Spurred on by recent positive results, I went straight for replacement (I didn’t test mine as I don’t have the equipment.)

My problems are now 95% cured. I Have had just one P2262 flag up in the two weeks since replacement but suspect I may still have carbon in my EGR valve, Intake valve and MAP sensor which I will clean in due course. No other faults have been logged.

Its possible the camshaft metal has got into the turbo bearings also. So far it seems ok and hopefully a carbon clean will rectify any remaining issues.

In conclusion, I suspect the poor acceleration and fuel economy may be caused by a worn exhaust camshaft and the fault codes by a worn vacuum pump. You may not have both conditions.

Hope this info helps someone.
Thanks for the info Joe, iv recently had the p258B00 warning for the vacuum pump. Brought it to a mazda dealer today and they said the vacuum pump was damaged and needs replacing. I'm booked in for Friday (2 days time) will report back if this works.

171 Posts

I had the camshaft replaced, my exhaust valves weren't pushed open anymore. hence the low mpg, low power, hesitation and very low power above 4000 rpm. The car is incredibly fast now (also had a remap so it ll make about 230 hp now) .

View attachment 246023
View attachment 246024
Worn camshaft is well known on certain vins, early 2013 due to the cam follower being too hard.

171 Posts
Hello All,

For a while, I've been experiencing intermittent issues with my Mazda 6.
My car does struggle sometimes whilst cruising between 1.8-2.5k rpm (as if it was choking, also hesitatates during acceleration).
It seems like the fuel consumption is higher than it should be.

I had it checked by a mechanic and no faults were found.
Had it fully serviced, replaced SCV valve, had the engine carbon cleaned which helped for a few days.
I've cleaned MAF & MAP sensors, which helped further (MAP was completely covered with carbon).
I wanted to get my EGR and Intake Manifold cleaned next (walnut blasting) as I suspect EGR valve could be causing it (DPF would be next on my list).

Whilst checking the live data I've noticed that:
-Charge Air Cooler Temperature Sensor 1 (Bank 1) is stuck at -40 degrees Celcius
-Exhaust Gas Temperature Sensor 4 (Bank 1) is also stuck at -40 degrees Celcius
What are your readings for these 2 sensors?

Don't worry about the -40C temp on the air side, I get that and the car runs ok.
If the fuel additive drops the temp in the DPF then you don't want to be using it. High temps burn off the carbon in the DPF as they are designed to do.

You should be achieving 50 mpg in the town and 60+ on a long run.
Any 2014 - 2016 (so far) may suffer from worn injectors and no amount of snake oil added will do any good.
Erkish is having that problem now, check out my replies.
People who have these problems often sell the car with the problem and don't say anything, so 2nd & 3rd owners inherit a problem.
I had my car from new, its 8 years old 70+k miles and I had to have a new set of injectors , late 40k's. Its a known problem but kept quiet as its expensive.

What you need to be checking on is Lube oil dilution and frequency of regens by subtracting two total regens and dividing by the miles between them, usually when you add diesel at 2-300 miles. Never let you tank go below 1/4. Ignore the Miles left screen, lot of nonsense.
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