sam255 Posted August 22 Share Posted August 22 I had an engine light come on today. When I plugged Carly in it came up with error number 245700. I checked the back pressure and it is not in MB it's in HPA so I'm not sure what the reading should be. I did clear codes and take it on a motorway run and the soot went down from 30g to 2g. Quote Link to comment Share on other sites More sharing options...
Andrew Posted August 22 Share Posted August 22 hPa is hectopascal 1 hPa = 1mb one millibar As a Civil Engineer, I need to think in terms of kN/m^2 for pressures and N/mm^2 for stress. Hate working in Pascals.... weird continental units.....🤪 Quote Link to comment Share on other sites More sharing options...
sam255 Posted August 22 Author Share Posted August 22 6 minutes ago, Andrew said: hPa is hectopascal 1 hPa = 1mb one millibar As a Civil Engineer, I need to think in terms of kN/m^2 for pressures and N/mm^2 for stress. Hate working in Pascals.... weird continental units.....🤪 Does that mean the back pressure is over 1000mb isn't that high ? If so what could be the cause of it ? I thought max limit is 300mb Quote Link to comment Share on other sites More sharing options...
Andrew Posted August 22 Share Posted August 22 Yes that would be correct at 1.2 bar. About 17psi in ye olde skool money. I've no idea what pressures DPF's run at, sorry. 1 Quote Link to comment Share on other sites More sharing options...
HandyAndy Posted August 24 Share Posted August 24 High back pressure warning indicates constriction within the dpf. Assuming it's not a faulty/failing pressure sensor then the options are clogged dpf itself, or of the bypass tube. The bypass tube is where the pressure sensor gets its comparison from. As you've done a run and the soot mass has dropped (dramatically) I'd guess it should now clear the fault. But if it built up to that extent it may indicate regeneration isn't taking place. Quote Link to comment Share on other sites More sharing options...
sam255 Posted August 24 Author Share Posted August 24 4 hours ago, HandyAndy said: High back pressure warning indicates constriction within the dpf. Assuming it's not a faulty/failing pressure sensor then the options are clogged dpf itself, or of the bypass tube. The bypass tube is where the pressure sensor gets its comparison from. As you've done a run and the soot mass has dropped (dramatically) I'd guess it should now clear the fault. But if it built up to that extent it may indicate regeneration isn't taking place. I called a dpf guy I know he said given the mileage I have done,it could be ash build up (255k miles) I haven't had the dpf cleaned or anything. He said the car is regenerating but the ash is most likely causing the high pressure and dpf taken off and cleaned in their cabinet machine. He will check on Tuesday. So will let you know. Quote Link to comment Share on other sites More sharing options...
HandyAndy Posted August 25 Share Posted August 25 If it's not been cleaned, like him my money's on that then. A proper bidirectional clean then refit and adaptations reset and you should be laughing. Quote Link to comment Share on other sites More sharing options...
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