Seeking Solutions for 2010 Mazda BT Series Diesel: Persistent Check Engine Light, Black Smoke, Power Loss, Unsteady Engine, and Poor Fuel Economy

Hey there! I've got some experience under my hood, mostly basic hands-on stuff. I had a similar quirk with my 2008 Mazda CX-7 diesel. It was coughing up more fumes than a chimney, and had me scratching my head for a bit. Turned out, like you guessed, the troublemaker in this story was the DPF, and it was severely overloaded. Had my bloke at the local garage take care of it. Cost me a tidy sum of 1325€, but she's all better now. So sounds like your BT might be dealing with a similar sort of mess. By the way, do you happen to know what codes your check engine light is throwing? It’d help to get a more detailed picture of what's going wrong under there. Cheers!

Hey, thanks for the swift response! Yeah, the DPF was bugging me too. Awfully nasty piece of work when it's not playing nice, isn't it? As for the check engine codes, PC2008 and PD1703 keep popping up on my reader. Was hesitant to get under the hood myself. With my BT clocking 163867 KM, thought it would be wiser to get a pro on it. I'm not ecstatic about the expense, but hey, if it gets my ride back to its former glory, I guess it's worth it. Preciate the help!

No worries, happy to help! Those codes you pointed out, PC2008 and PD1703, are indeed indicative of exhaust back pressure sensor issues and DPF malfunctioning. So, your hunch about the sensor being faulty wasn't off the mark. I sympathise with you about getting a pro to look at it – I was exactly there with my Mazda CX-7. Cleared out 1325€ to fix mine, but it was a sound investment in the long run as I got back the smooth ride and the fuel economy improved significantly. Like I said, start with the DPF. It's a bit of a brute when it's not behaving, but once it's sorted out, you should notice a difference. And don't forget to get that exhaust back pressure sensor looked at as well. Best of luck!

Cheers! Your advice was really helpful. The DPF and the exhaust back pressure sensor seem to be the culprits indeed. I'll be taking the old girl into the garage next week then, got an appointment already. Hopefully, the repair costs won't be more than what you had to shell out for your CX-7. Fingers crossed it solves our black smoke problem and we get back our power and improved fuel economy. Thanks again for the help, really appreciated it!