I've managed to solve the issue on my car. My Mazda 6 was not accelerating correctly and it was showing the Engine Warning Light, DSC Light and SCBS Malfunction. My diagnostic reader was giving me the following codes:
P0471- Exhaust Pressure Sensor A Circuit Range/Performance
P0472- Exhaust Pressure Sensor A Circuit Low
P2227- Barometric Pressure Circuit Range/Performance
The P0471 & P2227 only showed up very intermittently whereas the P0472 was constant.
I replaced the dual-hose exhaust pressure sensor to no avail, but it turns out the Mazda 2.2D has two seperate exhaust pressure sensors which I was initially unaware of. The sensor is at the rear of the engine behind the valve cover, near the turbocharger. You need to remove the plastic engine cover and heat shield to get to it.
I contacted Mazda and ordered a new sensor however this model of sensor has been discontinued and replaced with a new design. The old sensor was covered in carbon deposit so i suspect it had just become blocked and could no longer register the pressure (my car has only done 34,000 miles!!). The new sensor comes included with a shorter rubber hose, mounting bracket and extender cable which all need to be installed for the new sensor to fit correctly. It's quite a fiddly job and you'll need a pair of long-nose pliers to get the hose spring clamps off but it's doable. Once installed, I reconnected the battery and cleared the Engine Warning Light and the car is now running and accelerating normally again!!
Part Numbers:
Old Sensor- SH02-18-211C
New Sensor- SHY6-18-W00
All in all, the new sensor cost around £69 and about 45 mins to install. My local Arnold Clark Mazda quoted me £128 just to run a diagnostic check so instead I just bought a £20 code reader from Amazon. Hopefully this can help someone save some cash and get their car back on the road.