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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 21631
Experience:  BEng hons Mech engineering, in auto industry 22 years
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The DPF light on my 2007 Mazda 3 2.0D Sport started flashing

Resolved Question:

Hi, The DPF light on my 2007 Mazda 3 2.0D Sport started flashing a couple of weeks ago. There has been no difference it the way it performs (it certainly hasn't gone into limp mode) so I thought it was just a case of my independent mechanic not resetting it after I'd had it serviced a few months ago - which also happened last time they serviced it. This time however, they're saying they can't reset it and think it may need a whole new filter system. I'd welcome any advice. Many thanks, Paul.
Submitted: 1 year ago.
Category: Car
Customer: replied 1 year ago.
They've now told me they've tried to do a re-gen but it fails?
Expert:  Matt replied 1 year ago.
Hello if the ECU thinks the DPF is blocked then it won't allow full engine power so I'd suggest; taking the car for a long drive where you can keep the engine rpm up over 2000 rpm for around 30 mins this will get plenty of heat into the system and get the system into re-gen mode if that doesn't help then consider or even removing it completely as you'll still pass MOT's fine without it, the key thing is to have the ECU re-programmed so its no longer looking for it or On cars where the DPF is removed then typically you get more power and more mpg as it restricts the exhaust even when new
Customer: replied 1 year ago.
Thanks but that doesn't really tell me anything I hadn't already found out online for free. Plus as I'd stated I'm not experiencing any loss of power.
Expert:  Matt replied 1 year ago.
Hello Paul Ok in that case the DPF may be fine but the issue may be with the exhaust pressure sensor ? as just before the DPF there's a pressure tapping that runs off to a sensor, if this sensor is faulty or has a poor connection or wiring damage it will be delivering a false message to the ECU ? so I'd locate the sensor and check its wiring and connection as the next step - also check that any flexible pressure line that runs off the exhaust isn't blocked or broken
Expert:  Matt replied 1 year ago.
do you still need help?
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Customer: replied 1 year ago.
100 miles on it's still running fine so over the weekend I'm going to try and reset the light myself using methods I've found online before any further investigation.Thanks.